mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-11-01 00:48:50 +00:00
Code Issues Releases Wiki Activity
linux-stable/block/blk-mq.c
Jens Axboe e19b0f8391 block: flush plug based on hardware and software queue order 
commit 26fed4ac4e upstream.

We used to sort the plug list if we had multiple queues before dispatching
requests to the IO scheduler. This usually isn't needed, but for certain
workloads that interleave requests to disks, it's a less efficient to
process the plug list one-by-one if everything is interleaved.

Don't sort the list, but skip through it and flush out entries that have
the same target at the same time.

Fixes: df87eb0fce ("block: get rid of plug list sorting")
Reported-and-tested-by: Song Liu <song@kernel.org>
Reviewed-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-08 13:57:13 +02:00

4771 lines
118 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0
/*
* Block multiqueue core code
*
* Copyright (C) 2013-2014 Jens Axboe
* Copyright (C) 2013-2014 Christoph Hellwig
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/backing-dev.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/blk-integrity.h>
#include <linux/kmemleak.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/llist.h>
#include <linux/cpu.h>
#include <linux/cache.h>
#include <linux/sched/sysctl.h>
#include <linux/sched/topology.h>
#include <linux/sched/signal.h>
#include <linux/delay.h>
#include <linux/crash_dump.h>
#include <linux/prefetch.h>
#include <linux/blk-crypto.h>
#include <linux/part_stat.h>
#include <trace/events/block.h>
#include <linux/blk-mq.h>
#include <linux/t10-pi.h>
#include "blk.h"
#include "blk-mq.h"
#include "blk-mq-debugfs.h"
#include "blk-mq-tag.h"
#include "blk-pm.h"
#include "blk-stat.h"
#include "blk-mq-sched.h"
#include "blk-rq-qos.h"
static DEFINE_PER_CPU(struct llist_head, blk_cpu_done);
static void blk_mq_poll_stats_start(struct request_queue *q);
static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb);
static int blk_mq_poll_stats_bkt(const struct request *rq)
{
int ddir, sectors, bucket;
ddir = rq_data_dir(rq);
sectors = blk_rq_stats_sectors(rq);
bucket = ddir + 2 * ilog2(sectors);
if (bucket < 0)
return -1;
else if (bucket >= BLK_MQ_POLL_STATS_BKTS)
return ddir + BLK_MQ_POLL_STATS_BKTS - 2;
return bucket;
}
#define BLK_QC_T_SHIFT 16
#define BLK_QC_T_INTERNAL (1U << 31)
static inline struct blk_mq_hw_ctx *blk_qc_to_hctx(struct request_queue *q,
blk_qc_t qc)
{
return q->queue_hw_ctx[(qc & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT];
}
static inline struct request *blk_qc_to_rq(struct blk_mq_hw_ctx *hctx,
blk_qc_t qc)
{
unsigned int tag = qc & ((1U << BLK_QC_T_SHIFT) - 1);
if (qc & BLK_QC_T_INTERNAL)
return blk_mq_tag_to_rq(hctx->sched_tags, tag);
return blk_mq_tag_to_rq(hctx->tags, tag);
}
static inline blk_qc_t blk_rq_to_qc(struct request *rq)
{
return (rq->mq_hctx->queue_num << BLK_QC_T_SHIFT) |
(rq->tag != -1 ?
rq->tag : (rq->internal_tag | BLK_QC_T_INTERNAL));
}
/*
* Check if any of the ctx, dispatch list or elevator
* have pending work in this hardware queue.
*/
static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
{
return !list_empty_careful(&hctx->dispatch) ||
sbitmap_any_bit_set(&hctx->ctx_map) ||
blk_mq_sched_has_work(hctx);
}
/*
* Mark this ctx as having pending work in this hardware queue
*/
static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx)
{
const int bit = ctx->index_hw[hctx->type];
if (!sbitmap_test_bit(&hctx->ctx_map, bit))
sbitmap_set_bit(&hctx->ctx_map, bit);
}
static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx)
{
const int bit = ctx->index_hw[hctx->type];
sbitmap_clear_bit(&hctx->ctx_map, bit);
}
struct mq_inflight {
struct block_device *part;
unsigned int inflight[2];
};
static bool blk_mq_check_inflight(struct request *rq, void *priv,
bool reserved)
{
struct mq_inflight *mi = priv;
if ((!mi->part->bd_partno || rq->part == mi->part) &&
blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT)
mi->inflight[rq_data_dir(rq)]++;
return true;
}
unsigned int blk_mq_in_flight(struct request_queue *q,
struct block_device *part)
{
struct mq_inflight mi = { .part = part };
blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
return mi.inflight[0] + mi.inflight[1];
}
void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part,
unsigned int inflight[2])
{
struct mq_inflight mi = { .part = part };
blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
inflight[0] = mi.inflight[0];
inflight[1] = mi.inflight[1];
}
void blk_freeze_queue_start(struct request_queue *q)
{
mutex_lock(&q->mq_freeze_lock);
if (++q->mq_freeze_depth == 1) {
percpu_ref_kill(&q->q_usage_counter);
mutex_unlock(&q->mq_freeze_lock);
if (queue_is_mq(q))
blk_mq_run_hw_queues(q, false);
} else {
mutex_unlock(&q->mq_freeze_lock);
}
}
EXPORT_SYMBOL_GPL(blk_freeze_queue_start);
void blk_mq_freeze_queue_wait(struct request_queue *q)
{
wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter));
}
EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait);
int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
unsigned long timeout)
{
return wait_event_timeout(q->mq_freeze_wq,
percpu_ref_is_zero(&q->q_usage_counter),
timeout);
}
EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);
/*
* Guarantee no request is in use, so we can change any data structure of
* the queue afterward.
*/
void blk_freeze_queue(struct request_queue *q)
{
/*
* In the !blk_mq case we are only calling this to kill the
* q_usage_counter, otherwise this increases the freeze depth
* and waits for it to return to zero. For this reason there is
* no blk_unfreeze_queue(), and blk_freeze_queue() is not
* exported to drivers as the only user for unfreeze is blk_mq.
*/
blk_freeze_queue_start(q);
blk_mq_freeze_queue_wait(q);
}
void blk_mq_freeze_queue(struct request_queue *q)
{
/*
* ...just an alias to keep freeze and unfreeze actions balanced
* in the blk_mq_* namespace
*/
blk_freeze_queue(q);
}
EXPORT_SYMBOL_GPL(blk_mq_freeze_queue);
void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic)
{
mutex_lock(&q->mq_freeze_lock);
if (force_atomic)
q->q_usage_counter.data->force_atomic = true;
q->mq_freeze_depth--;
WARN_ON_ONCE(q->mq_freeze_depth < 0);
if (!q->mq_freeze_depth) {
percpu_ref_resurrect(&q->q_usage_counter);
wake_up_all(&q->mq_freeze_wq);
}
mutex_unlock(&q->mq_freeze_lock);
}
void blk_mq_unfreeze_queue(struct request_queue *q)
{
__blk_mq_unfreeze_queue(q, false);
}
EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
/*
* FIXME: replace the scsi_internal_device_*block_nowait() calls in the
* mpt3sas driver such that this function can be removed.
*/
void blk_mq_quiesce_queue_nowait(struct request_queue *q)
{
unsigned long flags;
spin_lock_irqsave(&q->queue_lock, flags);
if (!q->quiesce_depth++)
blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q);
spin_unlock_irqrestore(&q->queue_lock, flags);
}
EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait);
/**
* blk_mq_wait_quiesce_done() - wait until in-progress quiesce is done
* @q: request queue.
*
* Note: it is driver's responsibility for making sure that quiesce has
* been started.
*/
void blk_mq_wait_quiesce_done(struct request_queue *q)
{
if (blk_queue_has_srcu(q))
synchronize_srcu(q->srcu);
else
synchronize_rcu();
}
EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done);
/**
* blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
* @q: request queue.
*
* Note: this function does not prevent that the struct request end_io()
* callback function is invoked. Once this function is returned, we make
* sure no dispatch can happen until the queue is unquiesced via
* blk_mq_unquiesce_queue().
*/
void blk_mq_quiesce_queue(struct request_queue *q)
{
blk_mq_quiesce_queue_nowait(q);
blk_mq_wait_quiesce_done(q);
}
EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
/*
* blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
* @q: request queue.
*
* This function recovers queue into the state before quiescing
* which is done by blk_mq_quiesce_queue.
*/
void blk_mq_unquiesce_queue(struct request_queue *q)
{
unsigned long flags;
bool run_queue = false;
spin_lock_irqsave(&q->queue_lock, flags);
if (WARN_ON_ONCE(q->quiesce_depth <= 0)) {
;
} else if (!--q->quiesce_depth) {
blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q);
run_queue = true;
}
spin_unlock_irqrestore(&q->queue_lock, flags);
/* dispatch requests which are inserted during quiescing */
if (run_queue)
blk_mq_run_hw_queues(q, true);
}
EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
void blk_mq_wake_waiters(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
unsigned int i;
queue_for_each_hw_ctx(q, hctx, i)
if (blk_mq_hw_queue_mapped(hctx))
blk_mq_tag_wakeup_all(hctx->tags, true);
}
void blk_rq_init(struct request_queue *q, struct request *rq)
{
memset(rq, 0, sizeof(*rq));
INIT_LIST_HEAD(&rq->queuelist);
rq->q = q;
rq->__sector = (sector_t) -1;
INIT_HLIST_NODE(&rq->hash);
RB_CLEAR_NODE(&rq->rb_node);
rq->tag = BLK_MQ_NO_TAG;
rq->internal_tag = BLK_MQ_NO_TAG;
rq->start_time_ns = ktime_get_ns();
rq->part = NULL;
blk_crypto_rq_set_defaults(rq);
}
EXPORT_SYMBOL(blk_rq_init);
static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
struct blk_mq_tags *tags, unsigned int tag, u64 alloc_time_ns)
{
struct blk_mq_ctx *ctx = data->ctx;
struct blk_mq_hw_ctx *hctx = data->hctx;
struct request_queue *q = data->q;
struct request *rq = tags->static_rqs[tag];
rq->q = q;
rq->mq_ctx = ctx;
rq->mq_hctx = hctx;
rq->cmd_flags = data->cmd_flags;
if (data->flags & BLK_MQ_REQ_PM)
data->rq_flags |= RQF_PM;
if (blk_queue_io_stat(q))
data->rq_flags |= RQF_IO_STAT;
rq->rq_flags = data->rq_flags;
if (!(data->rq_flags & RQF_ELV)) {
rq->tag = tag;
rq->internal_tag = BLK_MQ_NO_TAG;
} else {
rq->tag = BLK_MQ_NO_TAG;
rq->internal_tag = tag;
}
rq->timeout = 0;
if (blk_mq_need_time_stamp(rq))
rq->start_time_ns = ktime_get_ns();
else
rq->start_time_ns = 0;
rq->part = NULL;
#ifdef CONFIG_BLK_RQ_ALLOC_TIME
rq->alloc_time_ns = alloc_time_ns;
#endif
rq->io_start_time_ns = 0;
rq->stats_sectors = 0;
rq->nr_phys_segments = 0;
#if defined(CONFIG_BLK_DEV_INTEGRITY)
rq->nr_integrity_segments = 0;
#endif
rq->end_io = NULL;
rq->end_io_data = NULL;
blk_crypto_rq_set_defaults(rq);
INIT_LIST_HEAD(&rq->queuelist);
/* tag was already set */
WRITE_ONCE(rq->deadline, 0);
req_ref_set(rq, 1);
if (rq->rq_flags & RQF_ELV) {
struct elevator_queue *e = data->q->elevator;
INIT_HLIST_NODE(&rq->hash);
RB_CLEAR_NODE(&rq->rb_node);
if (!op_is_flush(data->cmd_flags) &&
e->type->ops.prepare_request) {
e->type->ops.prepare_request(rq);
rq->rq_flags |= RQF_ELVPRIV;
}
}
return rq;
}
static inline struct request *
__blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data,
u64 alloc_time_ns)
{
unsigned int tag, tag_offset;
struct blk_mq_tags *tags;
struct request *rq;
unsigned long tag_mask;
int i, nr = 0;
tag_mask = blk_mq_get_tags(data, data->nr_tags, &tag_offset);
if (unlikely(!tag_mask))
return NULL;
tags = blk_mq_tags_from_data(data);
for (i = 0; tag_mask; i++) {
if (!(tag_mask & (1UL << i)))
continue;
tag = tag_offset + i;
prefetch(tags->static_rqs[tag]);
tag_mask &= ~(1UL << i);
rq = blk_mq_rq_ctx_init(data, tags, tag, alloc_time_ns);
rq_list_add(data->cached_rq, rq);
nr++;
}
/* caller already holds a reference, add for remainder */
percpu_ref_get_many(&data->q->q_usage_counter, nr - 1);
data->nr_tags -= nr;
return rq_list_pop(data->cached_rq);
}
static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data)
{
struct request_queue *q = data->q;
u64 alloc_time_ns = 0;
struct request *rq;
unsigned int tag;
/* alloc_time includes depth and tag waits */
if (blk_queue_rq_alloc_time(q))
alloc_time_ns = ktime_get_ns();
if (data->cmd_flags & REQ_NOWAIT)
data->flags |= BLK_MQ_REQ_NOWAIT;
if (q->elevator) {
struct elevator_queue *e = q->elevator;
data->rq_flags |= RQF_ELV;
/*
* Flush/passthrough requests are special and go directly to the
* dispatch list. Don't include reserved tags in the
* limiting, as it isn't useful.
*/
if (!op_is_flush(data->cmd_flags) &&
!blk_op_is_passthrough(data->cmd_flags) &&
e->type->ops.limit_depth &&
!(data->flags & BLK_MQ_REQ_RESERVED))
e->type->ops.limit_depth(data->cmd_flags, data);
}
retry:
data->ctx = blk_mq_get_ctx(q);
data->hctx = blk_mq_map_queue(q, data->cmd_flags, data->ctx);
if (!(data->rq_flags & RQF_ELV))
blk_mq_tag_busy(data->hctx);
/*
* Try batched alloc if we want more than 1 tag.
*/
if (data->nr_tags > 1) {
rq = __blk_mq_alloc_requests_batch(data, alloc_time_ns);
if (rq)
return rq;
data->nr_tags = 1;
}
/*
* Waiting allocations only fail because of an inactive hctx. In that
* case just retry the hctx assignment and tag allocation as CPU hotplug
* should have migrated us to an online CPU by now.
*/
tag = blk_mq_get_tag(data);
if (tag == BLK_MQ_NO_TAG) {
if (data->flags & BLK_MQ_REQ_NOWAIT)
return NULL;
/*
* Give up the CPU and sleep for a random short time to
* ensure that thread using a realtime scheduling class
* are migrated off the CPU, and thus off the hctx that
* is going away.
*/
msleep(3);
goto retry;
}
return blk_mq_rq_ctx_init(data, blk_mq_tags_from_data(data), tag,
alloc_time_ns);
}
struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,
blk_mq_req_flags_t flags)
{
struct blk_mq_alloc_data data = {
.q = q,
.flags = flags,
.cmd_flags = op,
.nr_tags = 1,
};
struct request *rq;
int ret;
ret = blk_queue_enter(q, flags);
if (ret)
return ERR_PTR(ret);
rq = __blk_mq_alloc_requests(&data);
if (!rq)
goto out_queue_exit;
rq->__data_len = 0;
rq->__sector = (sector_t) -1;
rq->bio = rq->biotail = NULL;
return rq;
out_queue_exit:
blk_queue_exit(q);
return ERR_PTR(-EWOULDBLOCK);
}
EXPORT_SYMBOL(blk_mq_alloc_request);
struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
unsigned int op, blk_mq_req_flags_t flags, unsigned int hctx_idx)
{
struct blk_mq_alloc_data data = {
.q = q,
.flags = flags,
.cmd_flags = op,
.nr_tags = 1,
};
u64 alloc_time_ns = 0;
unsigned int cpu;
unsigned int tag;
int ret;
/* alloc_time includes depth and tag waits */
if (blk_queue_rq_alloc_time(q))
alloc_time_ns = ktime_get_ns();
/*
* If the tag allocator sleeps we could get an allocation for a
* different hardware context. No need to complicate the low level
* allocator for this for the rare use case of a command tied to
* a specific queue.
*/
if (WARN_ON_ONCE(!(flags & (BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_RESERVED))))
return ERR_PTR(-EINVAL);
if (hctx_idx >= q->nr_hw_queues)
return ERR_PTR(-EIO);
ret = blk_queue_enter(q, flags);
if (ret)
return ERR_PTR(ret);
/*
* Check if the hardware context is actually mapped to anything.
* If not tell the caller that it should skip this queue.
*/
ret = -EXDEV;
data.hctx = q->queue_hw_ctx[hctx_idx];
if (!blk_mq_hw_queue_mapped(data.hctx))
goto out_queue_exit;
cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask);
data.ctx = __blk_mq_get_ctx(q, cpu);
if (!q->elevator)
blk_mq_tag_busy(data.hctx);
else
data.rq_flags |= RQF_ELV;
ret = -EWOULDBLOCK;
tag = blk_mq_get_tag(&data);
if (tag == BLK_MQ_NO_TAG)
goto out_queue_exit;
return blk_mq_rq_ctx_init(&data, blk_mq_tags_from_data(&data), tag,
alloc_time_ns);
out_queue_exit:
blk_queue_exit(q);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
static void __blk_mq_free_request(struct request *rq)
{
struct request_queue *q = rq->q;
struct blk_mq_ctx *ctx = rq->mq_ctx;
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
const int sched_tag = rq->internal_tag;
blk_crypto_free_request(rq);
blk_pm_mark_last_busy(rq);
rq->mq_hctx = NULL;
if (rq->tag != BLK_MQ_NO_TAG)
blk_mq_put_tag(hctx->tags, ctx, rq->tag);
if (sched_tag != BLK_MQ_NO_TAG)
blk_mq_put_tag(hctx->sched_tags, ctx, sched_tag);
blk_mq_sched_restart(hctx);
blk_queue_exit(q);
}
void blk_mq_free_request(struct request *rq)
{
struct request_queue *q = rq->q;
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
if ((rq->rq_flags & RQF_ELVPRIV) &&
q->elevator->type->ops.finish_request)
q->elevator->type->ops.finish_request(rq);
if (rq->rq_flags & RQF_MQ_INFLIGHT)
__blk_mq_dec_active_requests(hctx);
if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
laptop_io_completion(q->disk->bdi);
rq_qos_done(q, rq);
WRITE_ONCE(rq->state, MQ_RQ_IDLE);
if (req_ref_put_and_test(rq))
__blk_mq_free_request(rq);
}
EXPORT_SYMBOL_GPL(blk_mq_free_request);
void blk_mq_free_plug_rqs(struct blk_plug *plug)
{
struct request *rq;
while ((rq = rq_list_pop(&plug->cached_rq)) != NULL)
blk_mq_free_request(rq);
}
void blk_dump_rq_flags(struct request *rq, char *msg)
{
printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg,
rq->q->disk ? rq->q->disk->disk_name : "?",
(unsigned long long) rq->cmd_flags);
printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
(unsigned long long)blk_rq_pos(rq),
blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
printk(KERN_INFO " bio %p, biotail %p, len %u\n",
rq->bio, rq->biotail, blk_rq_bytes(rq));
}
EXPORT_SYMBOL(blk_dump_rq_flags);
static void req_bio_endio(struct request *rq, struct bio *bio,
unsigned int nbytes, blk_status_t error)
{
if (unlikely(error)) {
bio->bi_status = error;
} else if (req_op(rq) == REQ_OP_ZONE_APPEND) {
/*
* Partial zone append completions cannot be supported as the
* BIO fragments may end up not being written sequentially.
*/
if (bio->bi_iter.bi_size != nbytes)
bio->bi_status = BLK_STS_IOERR;
else
bio->bi_iter.bi_sector = rq->__sector;
}
bio_advance(bio, nbytes);
if (unlikely(rq->rq_flags & RQF_QUIET))
bio_set_flag(bio, BIO_QUIET);
/* don't actually finish bio if it's part of flush sequence */
if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ))
bio_endio(bio);
}
static void blk_account_io_completion(struct request *req, unsigned int bytes)
{
if (req->part && blk_do_io_stat(req)) {
const int sgrp = op_stat_group(req_op(req));
part_stat_lock();
part_stat_add(req->part, sectors[sgrp], bytes >> 9);
part_stat_unlock();
}
}
static void blk_print_req_error(struct request *req, blk_status_t status)
{
printk_ratelimited(KERN_ERR
"%s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x "
"phys_seg %u prio class %u\n",
blk_status_to_str(status),
req->q->disk ? req->q->disk->disk_name : "?",
blk_rq_pos(req), req_op(req), blk_op_str(req_op(req)),
req->cmd_flags & ~REQ_OP_MASK,
req->nr_phys_segments,
IOPRIO_PRIO_CLASS(req->ioprio));
}
/*
* Fully end IO on a request. Does not support partial completions, or
* errors.
*/
static void blk_complete_request(struct request *req)
{
const bool is_flush = (req->rq_flags & RQF_FLUSH_SEQ) != 0;
int total_bytes = blk_rq_bytes(req);
struct bio *bio = req->bio;
trace_block_rq_complete(req, BLK_STS_OK, total_bytes);
if (!bio)
return;
#ifdef CONFIG_BLK_DEV_INTEGRITY
if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ)
req->q->integrity.profile->complete_fn(req, total_bytes);
#endif
blk_account_io_completion(req, total_bytes);
do {
struct bio *next = bio->bi_next;
/* Completion has already been traced */
bio_clear_flag(bio, BIO_TRACE_COMPLETION);
if (req_op(req) == REQ_OP_ZONE_APPEND)
bio->bi_iter.bi_sector = req->__sector;
if (!is_flush)
bio_endio(bio);
bio = next;
} while (bio);
/*
* Reset counters so that the request stacking driver
* can find how many bytes remain in the request
* later.
*/
req->bio = NULL;
req->__data_len = 0;
}
/**
* blk_update_request - Complete multiple bytes without completing the request
* @req: the request being processed
* @error: block status code
* @nr_bytes: number of bytes to complete for @req
*
* Description:
* Ends I/O on a number of bytes attached to @req, but doesn't complete
* the request structure even if @req doesn't have leftover.
* If @req has leftover, sets it up for the next range of segments.
*
* Passing the result of blk_rq_bytes() as @nr_bytes guarantees
* %false return from this function.
*
* Note:
* The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in this function
* except in the consistency check at the end of this function.
*
* Return:
* %false - this request doesn't have any more data
* %true - this request has more data
**/
bool blk_update_request(struct request *req, blk_status_t error,
unsigned int nr_bytes)
{
int total_bytes;
trace_block_rq_complete(req, error, nr_bytes);
if (!req->bio)
return false;
#ifdef CONFIG_BLK_DEV_INTEGRITY
if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ &&
error == BLK_STS_OK)
req->q->integrity.profile->complete_fn(req, nr_bytes);
#endif
if (unlikely(error && !blk_rq_is_passthrough(req) &&
!(req->rq_flags & RQF_QUIET)))
blk_print_req_error(req, error);
blk_account_io_completion(req, nr_bytes);
total_bytes = 0;
while (req->bio) {
struct bio *bio = req->bio;
unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
if (bio_bytes == bio->bi_iter.bi_size)
req->bio = bio->bi_next;
/* Completion has already been traced */
bio_clear_flag(bio, BIO_TRACE_COMPLETION);
req_bio_endio(req, bio, bio_bytes, error);
total_bytes += bio_bytes;
nr_bytes -= bio_bytes;
if (!nr_bytes)
break;
}
/*
* completely done
*/
if (!req->bio) {
/*
* Reset counters so that the request stacking driver
* can find how many bytes remain in the request
* later.
*/
req->__data_len = 0;
return false;
}
req->__data_len -= total_bytes;
/* update sector only for requests with clear definition of sector */
if (!blk_rq_is_passthrough(req))
req->__sector += total_bytes >> 9;
/* mixed attributes always follow the first bio */
if (req->rq_flags & RQF_MIXED_MERGE) {
req->cmd_flags &= ~REQ_FAILFAST_MASK;
req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK;
}
if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) {
/*
* If total number of sectors is less than the first segment
* size, something has gone terribly wrong.
*/
if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
blk_dump_rq_flags(req, "request botched");
req->__data_len = blk_rq_cur_bytes(req);
}
/* recalculate the number of segments */
req->nr_phys_segments = blk_recalc_rq_segments(req);
}
return true;
}
EXPORT_SYMBOL_GPL(blk_update_request);
static void __blk_account_io_done(struct request *req, u64 now)
{
const int sgrp = op_stat_group(req_op(req));
part_stat_lock();
update_io_ticks(req->part, jiffies, true);
part_stat_inc(req->part, ios[sgrp]);
part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
part_stat_unlock();
}
static inline void blk_account_io_done(struct request *req, u64 now)
{
/*
* Account IO completion. flush_rq isn't accounted as a
* normal IO on queueing nor completion. Accounting the
* containing request is enough.
*/
if (blk_do_io_stat(req) && req->part &&
!(req->rq_flags & RQF_FLUSH_SEQ))
__blk_account_io_done(req, now);
}
static void __blk_account_io_start(struct request *rq)
{
/* passthrough requests can hold bios that do not have ->bi_bdev set */
if (rq->bio && rq->bio->bi_bdev)
rq->part = rq->bio->bi_bdev;
else if (rq->q->disk)
rq->part = rq->q->disk->part0;
part_stat_lock();
update_io_ticks(rq->part, jiffies, false);
part_stat_unlock();
}
static inline void blk_account_io_start(struct request *req)
{
if (blk_do_io_stat(req))
__blk_account_io_start(req);
}
static inline void __blk_mq_end_request_acct(struct request *rq, u64 now)
{
if (rq->rq_flags & RQF_STATS) {
blk_mq_poll_stats_start(rq->q);
blk_stat_add(rq, now);
}
blk_mq_sched_completed_request(rq, now);
blk_account_io_done(rq, now);
}
inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
{
if (blk_mq_need_time_stamp(rq))
__blk_mq_end_request_acct(rq, ktime_get_ns());
if (rq->end_io) {
rq_qos_done(rq->q, rq);
rq->end_io(rq, error);
} else {
blk_mq_free_request(rq);
}
}
EXPORT_SYMBOL(__blk_mq_end_request);
void blk_mq_end_request(struct request *rq, blk_status_t error)
{
if (blk_update_request(rq, error, blk_rq_bytes(rq)))
BUG();
__blk_mq_end_request(rq, error);
}
EXPORT_SYMBOL(blk_mq_end_request);
#define TAG_COMP_BATCH 32
static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx *hctx,
int *tag_array, int nr_tags)
{
struct request_queue *q = hctx->queue;
/*
* All requests should have been marked as RQF_MQ_INFLIGHT, so
* update hctx->nr_active in batch
*/
if (hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
__blk_mq_sub_active_requests(hctx, nr_tags);
blk_mq_put_tags(hctx->tags, tag_array, nr_tags);
percpu_ref_put_many(&q->q_usage_counter, nr_tags);
}
void blk_mq_end_request_batch(struct io_comp_batch *iob)
{
int tags[TAG_COMP_BATCH], nr_tags = 0;
struct blk_mq_hw_ctx *cur_hctx = NULL;
struct request *rq;
u64 now = 0;
if (iob->need_ts)
now = ktime_get_ns();
while ((rq = rq_list_pop(&iob->req_list)) != NULL) {
prefetch(rq->bio);
prefetch(rq->rq_next);
blk_complete_request(rq);
if (iob->need_ts)
__blk_mq_end_request_acct(rq, now);
rq_qos_done(rq->q, rq);
WRITE_ONCE(rq->state, MQ_RQ_IDLE);
if (!req_ref_put_and_test(rq))
continue;
blk_crypto_free_request(rq);
blk_pm_mark_last_busy(rq);
if (nr_tags == TAG_COMP_BATCH || cur_hctx != rq->mq_hctx) {
if (cur_hctx)
blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
nr_tags = 0;
cur_hctx = rq->mq_hctx;
}
tags[nr_tags++] = rq->tag;
}
if (nr_tags)
blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
}
EXPORT_SYMBOL_GPL(blk_mq_end_request_batch);
static void blk_complete_reqs(struct llist_head *list)
{
struct llist_node *entry = llist_reverse_order(llist_del_all(list));
struct request *rq, *next;
llist_for_each_entry_safe(rq, next, entry, ipi_list)
rq->q->mq_ops->complete(rq);
}
static __latent_entropy void blk_done_softirq(struct softirq_action *h)
{
blk_complete_reqs(this_cpu_ptr(&blk_cpu_done));
}
static int blk_softirq_cpu_dead(unsigned int cpu)
{
blk_complete_reqs(&per_cpu(blk_cpu_done, cpu));
return 0;
}
static void __blk_mq_complete_request_remote(void *data)
{
__raise_softirq_irqoff(BLOCK_SOFTIRQ);
}
static inline bool blk_mq_complete_need_ipi(struct request *rq)
{
int cpu = raw_smp_processor_id();
if (!IS_ENABLED(CONFIG_SMP) ||
!test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags))
return false;
/*
* With force threaded interrupts enabled, raising softirq from an SMP
* function call will always result in waking the ksoftirqd thread.
* This is probably worse than completing the request on a different
* cache domain.
*/
if (force_irqthreads())
return false;
/* same CPU or cache domain? Complete locally */
if (cpu == rq->mq_ctx->cpu ||
(!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags) &&
cpus_share_cache(cpu, rq->mq_ctx->cpu)))
return false;
/* don't try to IPI to an offline CPU */
return cpu_online(rq->mq_ctx->cpu);
}
static void blk_mq_complete_send_ipi(struct request *rq)
{
struct llist_head *list;
unsigned int cpu;
cpu = rq->mq_ctx->cpu;
list = &per_cpu(blk_cpu_done, cpu);
if (llist_add(&rq->ipi_list, list)) {
INIT_CSD(&rq->csd, __blk_mq_complete_request_remote, rq);
smp_call_function_single_async(cpu, &rq->csd);
}
}
static void blk_mq_raise_softirq(struct request *rq)
{
struct llist_head *list;
preempt_disable();
list = this_cpu_ptr(&blk_cpu_done);
if (llist_add(&rq->ipi_list, list))
raise_softirq(BLOCK_SOFTIRQ);
preempt_enable();
}
bool blk_mq_complete_request_remote(struct request *rq)
{
WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
/*
* For a polled request, always complete locallly, it's pointless
* to redirect the completion.
*/
if (rq->cmd_flags & REQ_POLLED)
return false;
if (blk_mq_complete_need_ipi(rq)) {
blk_mq_complete_send_ipi(rq);
return true;
}
if (rq->q->nr_hw_queues == 1) {
blk_mq_raise_softirq(rq);
return true;
}
return false;
}
EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote);
/**
* blk_mq_complete_request - end I/O on a request
* @rq: the request being processed
*
* Description:
* Complete a request by scheduling the ->complete_rq operation.
**/
void blk_mq_complete_request(struct request *rq)
{
if (!blk_mq_complete_request_remote(rq))
rq->q->mq_ops->complete(rq);
}
EXPORT_SYMBOL(blk_mq_complete_request);
/**
* blk_mq_start_request - Start processing a request
* @rq: Pointer to request to be started
*
* Function used by device drivers to notify the block layer that a request
* is going to be processed now, so blk layer can do proper initializations
* such as starting the timeout timer.
*/
void blk_mq_start_request(struct request *rq)
{
struct request_queue *q = rq->q;
trace_block_rq_issue(rq);
if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) {
u64 start_time;
#ifdef CONFIG_BLK_CGROUP
if (rq->bio)
start_time = bio_issue_time(&rq->bio->bi_issue);
else
#endif
start_time = ktime_get_ns();
rq->io_start_time_ns = start_time;
rq->stats_sectors = blk_rq_sectors(rq);
rq->rq_flags |= RQF_STATS;
rq_qos_issue(q, rq);
}
WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE);
blk_add_timer(rq);
WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT);
#ifdef CONFIG_BLK_DEV_INTEGRITY
if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE)
q->integrity.profile->prepare_fn(rq);
#endif
if (rq->bio && rq->bio->bi_opf & REQ_POLLED)
WRITE_ONCE(rq->bio->bi_cookie, blk_rq_to_qc(rq));
}
EXPORT_SYMBOL(blk_mq_start_request);
/**
* blk_end_sync_rq - executes a completion event on a request
* @rq: request to complete
* @error: end I/O status of the request
*/
static void blk_end_sync_rq(struct request *rq, blk_status_t error)
{
struct completion *waiting = rq->end_io_data;
rq->end_io_data = (void *)(uintptr_t)error;
/*
* complete last, if this is a stack request the process (and thus
* the rq pointer) could be invalid right after this complete()
*/
complete(waiting);
}
/**
* blk_execute_rq_nowait - insert a request to I/O scheduler for execution
* @rq: request to insert
* @at_head: insert request at head or tail of queue
* @done: I/O completion handler
*
* Description:
* Insert a fully prepared request at the back of the I/O scheduler queue
* for execution. Don't wait for completion.
*
* Note:
* This function will invoke @done directly if the queue is dead.
*/
void blk_execute_rq_nowait(struct request *rq, bool at_head, rq_end_io_fn *done)
{
WARN_ON(irqs_disabled());
WARN_ON(!blk_rq_is_passthrough(rq));
rq->end_io = done;
blk_account_io_start(rq);
/*
* don't check dying flag for MQ because the request won't
* be reused after dying flag is set
*/
blk_mq_sched_insert_request(rq, at_head, true, false);
}
EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
static bool blk_rq_is_poll(struct request *rq)
{
if (!rq->mq_hctx)
return false;
if (rq->mq_hctx->type != HCTX_TYPE_POLL)
return false;
if (WARN_ON_ONCE(!rq->bio))
return false;
return true;
}
static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
{
do {
bio_poll(rq->bio, NULL, 0);
cond_resched();
} while (!completion_done(wait));
}
/**
* blk_execute_rq - insert a request into queue for execution
* @rq: request to insert
* @at_head: insert request at head or tail of queue
*
* Description:
* Insert a fully prepared request at the back of the I/O scheduler queue
* for execution and wait for completion.
* Return: The blk_status_t result provided to blk_mq_end_request().
*/
blk_status_t blk_execute_rq(struct request *rq, bool at_head)
{
DECLARE_COMPLETION_ONSTACK(wait);
unsigned long hang_check;
rq->end_io_data = &wait;
blk_execute_rq_nowait(rq, at_head, blk_end_sync_rq);
/* Prevent hang_check timer from firing at us during very long I/O */
hang_check = sysctl_hung_task_timeout_secs;
if (blk_rq_is_poll(rq))
blk_rq_poll_completion(rq, &wait);
else if (hang_check)
while (!wait_for_completion_io_timeout(&wait,
hang_check * (HZ/2)))
;
else
wait_for_completion_io(&wait);
return (blk_status_t)(uintptr_t)rq->end_io_data;
}
EXPORT_SYMBOL(blk_execute_rq);
static void __blk_mq_requeue_request(struct request *rq)
{
struct request_queue *q = rq->q;
blk_mq_put_driver_tag(rq);
trace_block_rq_requeue(rq);
rq_qos_requeue(q, rq);
if (blk_mq_request_started(rq)) {
WRITE_ONCE(rq->state, MQ_RQ_IDLE);
rq->rq_flags &= ~RQF_TIMED_OUT;
}
}
void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
{
__blk_mq_requeue_request(rq);
/* this request will be re-inserted to io scheduler queue */
blk_mq_sched_requeue_request(rq);
blk_mq_add_to_requeue_list(rq, true, kick_requeue_list);
}
EXPORT_SYMBOL(blk_mq_requeue_request);
static void blk_mq_requeue_work(struct work_struct *work)
{
struct request_queue *q =
container_of(work, struct request_queue, requeue_work.work);
LIST_HEAD(rq_list);
struct request *rq, *next;
spin_lock_irq(&q->requeue_lock);
list_splice_init(&q->requeue_list, &rq_list);
spin_unlock_irq(&q->requeue_lock);
list_for_each_entry_safe(rq, next, &rq_list, queuelist) {
if (!(rq->rq_flags & (RQF_SOFTBARRIER | RQF_DONTPREP)))
continue;
rq->rq_flags &= ~RQF_SOFTBARRIER;
list_del_init(&rq->queuelist);
/*
* If RQF_DONTPREP, rq has contained some driver specific
* data, so insert it to hctx dispatch list to avoid any
* merge.
*/
if (rq->rq_flags & RQF_DONTPREP)
blk_mq_request_bypass_insert(rq, false, false);
else
blk_mq_sched_insert_request(rq, true, false, false);
}
while (!list_empty(&rq_list)) {
rq = list_entry(rq_list.next, struct request, queuelist);
list_del_init(&rq->queuelist);
blk_mq_sched_insert_request(rq, false, false, false);
}
blk_mq_run_hw_queues(q, false);
}
void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
bool kick_requeue_list)
{
struct request_queue *q = rq->q;
unsigned long flags;
/*
* We abuse this flag that is otherwise used by the I/O scheduler to
* request head insertion from the workqueue.
*/
BUG_ON(rq->rq_flags & RQF_SOFTBARRIER);
spin_lock_irqsave(&q->requeue_lock, flags);
if (at_head) {
rq->rq_flags |= RQF_SOFTBARRIER;
list_add(&rq->queuelist, &q->requeue_list);
} else {
list_add_tail(&rq->queuelist, &q->requeue_list);
}
spin_unlock_irqrestore(&q->requeue_lock, flags);
if (kick_requeue_list)
blk_mq_kick_requeue_list(q);
}
void blk_mq_kick_requeue_list(struct request_queue *q)
{
kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0);
}
EXPORT_SYMBOL(blk_mq_kick_requeue_list);
void blk_mq_delay_kick_requeue_list(struct request_queue *q,
unsigned long msecs)
{
kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work,
msecs_to_jiffies(msecs));
}
EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
static bool blk_mq_rq_inflight(struct request *rq, void *priv,
bool reserved)
{
/*
* If we find a request that isn't idle we know the queue is busy
* as it's checked in the iter.
* Return false to stop the iteration.
*/
if (blk_mq_request_started(rq)) {
bool *busy = priv;
*busy = true;
return false;
}
return true;
}
bool blk_mq_queue_inflight(struct request_queue *q)
{
bool busy = false;
blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy);
return busy;
}
EXPORT_SYMBOL_GPL(blk_mq_queue_inflight);
static void blk_mq_rq_timed_out(struct request *req, bool reserved)
{
req->rq_flags |= RQF_TIMED_OUT;
if (req->q->mq_ops->timeout) {
enum blk_eh_timer_return ret;
ret = req->q->mq_ops->timeout(req, reserved);
if (ret == BLK_EH_DONE)
return;
WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER);
}
blk_add_timer(req);
}
static bool blk_mq_req_expired(struct request *rq, unsigned long *next)
{
unsigned long deadline;
if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT)
return false;
if (rq->rq_flags & RQF_TIMED_OUT)
return false;
deadline = READ_ONCE(rq->deadline);
if (time_after_eq(jiffies, deadline))
return true;
if (*next == 0)
*next = deadline;
else if (time_after(*next, deadline))
*next = deadline;
return false;
}
void blk_mq_put_rq_ref(struct request *rq)
{
if (is_flush_rq(rq))
rq->end_io(rq, 0);
else if (req_ref_put_and_test(rq))
__blk_mq_free_request(rq);
}
static bool blk_mq_check_expired(struct request *rq, void *priv, bool reserved)
{
unsigned long *next = priv;
/*
* blk_mq_queue_tag_busy_iter() has locked the request, so it cannot
* be reallocated underneath the timeout handler's processing, then
* the expire check is reliable. If the request is not expired, then
* it was completed and reallocated as a new request after returning
* from blk_mq_check_expired().
*/
if (blk_mq_req_expired(rq, next))
blk_mq_rq_timed_out(rq, reserved);
return true;
}
static void blk_mq_timeout_work(struct work_struct *work)
{
struct request_queue *q =
container_of(work, struct request_queue, timeout_work);
unsigned long next = 0;
struct blk_mq_hw_ctx *hctx;
int i;
/* A deadlock might occur if a request is stuck requiring a
* timeout at the same time a queue freeze is waiting
* completion, since the timeout code would not be able to
* acquire the queue reference here.
*
* That's why we don't use blk_queue_enter here; instead, we use
* percpu_ref_tryget directly, because we need to be able to
* obtain a reference even in the short window between the queue
* starting to freeze, by dropping the first reference in
* blk_freeze_queue_start, and the moment the last request is
* consumed, marked by the instant q_usage_counter reaches
* zero.
*/
if (!percpu_ref_tryget(&q->q_usage_counter))
return;
blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &next);
if (next != 0) {
mod_timer(&q->timeout, next);
} else {
/*
* Request timeouts are handled as a forward rolling timer. If
* we end up here it means that no requests are pending and
* also that no request has been pending for a while. Mark
* each hctx as idle.
*/
queue_for_each_hw_ctx(q, hctx, i) {
/* the hctx may be unmapped, so check it here */
if (blk_mq_hw_queue_mapped(hctx))
blk_mq_tag_idle(hctx);
}
}
blk_queue_exit(q);
}
struct flush_busy_ctx_data {
struct blk_mq_hw_ctx *hctx;
struct list_head *list;
};
static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
{
struct flush_busy_ctx_data *flush_data = data;
struct blk_mq_hw_ctx *hctx = flush_data->hctx;
struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
enum hctx_type type = hctx->type;
spin_lock(&ctx->lock);
list_splice_tail_init(&ctx->rq_lists[type], flush_data->list);
sbitmap_clear_bit(sb, bitnr);
spin_unlock(&ctx->lock);
return true;
}
/*
* Process software queues that have been marked busy, splicing them
* to the for-dispatch
*/
void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
{
struct flush_busy_ctx_data data = {
.hctx = hctx,
.list = list,
};
sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
}
EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs);
struct dispatch_rq_data {
struct blk_mq_hw_ctx *hctx;
struct request *rq;
};
static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr,
void *data)
{
struct dispatch_rq_data *dispatch_data = data;
struct blk_mq_hw_ctx *hctx = dispatch_data->hctx;
struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
enum hctx_type type = hctx->type;
spin_lock(&ctx->lock);
if (!list_empty(&ctx->rq_lists[type])) {
dispatch_data->rq = list_entry_rq(ctx->rq_lists[type].next);
list_del_init(&dispatch_data->rq->queuelist);
if (list_empty(&ctx->rq_lists[type]))
sbitmap_clear_bit(sb, bitnr);
}
spin_unlock(&ctx->lock);
return !dispatch_data->rq;
}
struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *start)
{
unsigned off = start ? start->index_hw[hctx->type] : 0;
struct dispatch_rq_data data = {
.hctx = hctx,
.rq = NULL,
};
__sbitmap_for_each_set(&hctx->ctx_map, off,
dispatch_rq_from_ctx, &data);
return data.rq;
}
static bool __blk_mq_alloc_driver_tag(struct request *rq)
{
struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags;
unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags;
int tag;
blk_mq_tag_busy(rq->mq_hctx);
if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) {
bt = &rq->mq_hctx->tags->breserved_tags;
tag_offset = 0;
} else {
if (!hctx_may_queue(rq->mq_hctx, bt))
return false;
}
tag = __sbitmap_queue_get(bt);
if (tag == BLK_MQ_NO_TAG)
return false;
rq->tag = tag + tag_offset;
return true;
}
bool __blk_mq_get_driver_tag(struct blk_mq_hw_ctx *hctx, struct request *rq)
{
if (rq->tag == BLK_MQ_NO_TAG && !__blk_mq_alloc_driver_tag(rq))
return false;
if ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&
!(rq->rq_flags & RQF_MQ_INFLIGHT)) {
rq->rq_flags |= RQF_MQ_INFLIGHT;
__blk_mq_inc_active_requests(hctx);
}
hctx->tags->rqs[rq->tag] = rq;
return true;
}
static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
int flags, void *key)
{
struct blk_mq_hw_ctx *hctx;
hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait);
spin_lock(&hctx->dispatch_wait_lock);
if (!list_empty(&wait->entry)) {
struct sbitmap_queue *sbq;
list_del_init(&wait->entry);
sbq = &hctx->tags->bitmap_tags;
atomic_dec(&sbq->ws_active);
}
spin_unlock(&hctx->dispatch_wait_lock);
blk_mq_run_hw_queue(hctx, true);
return 1;
}
/*
* Mark us waiting for a tag. For shared tags, this involves hooking us into
* the tag wakeups. For non-shared tags, we can simply mark us needing a
* restart. For both cases, take care to check the condition again after
* marking us as waiting.
*/
static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
struct request *rq)
{
struct sbitmap_queue *sbq = &hctx->tags->bitmap_tags;
struct wait_queue_head *wq;
wait_queue_entry_t *wait;
bool ret;
if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
blk_mq_sched_mark_restart_hctx(hctx);
/*
* It's possible that a tag was freed in the window between the
* allocation failure and adding the hardware queue to the wait
* queue.
*
* Don't clear RESTART here, someone else could have set it.
* At most this will cost an extra queue run.
*/
return blk_mq_get_driver_tag(rq);
}
wait = &hctx->dispatch_wait;
if (!list_empty_careful(&wait->entry))
return false;
wq = &bt_wait_ptr(sbq, hctx)->wait;
spin_lock_irq(&wq->lock);
spin_lock(&hctx->dispatch_wait_lock);
if (!list_empty(&wait->entry)) {
spin_unlock(&hctx->dispatch_wait_lock);
spin_unlock_irq(&wq->lock);
return false;
}
atomic_inc(&sbq->ws_active);
wait->flags &= ~WQ_FLAG_EXCLUSIVE;
__add_wait_queue(wq, wait);
/*
* It's possible that a tag was freed in the window between the
* allocation failure and adding the hardware queue to the wait
* queue.
*/
ret = blk_mq_get_driver_tag(rq);
if (!ret) {
spin_unlock(&hctx->dispatch_wait_lock);
spin_unlock_irq(&wq->lock);
return false;
}
/*
* We got a tag, remove ourselves from the wait queue to ensure
* someone else gets the wakeup.
*/
list_del_init(&wait->entry);
atomic_dec(&sbq->ws_active);
spin_unlock(&hctx->dispatch_wait_lock);
spin_unlock_irq(&wq->lock);
return true;
}
#define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
#define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
/*
* Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
* - EWMA is one simple way to compute running average value
* - weight(7/8 and 1/8) is applied so that it can decrease exponentially
* - take 4 as factor for avoiding to get too small(0) result, and this
* factor doesn't matter because EWMA decreases exponentially
*/
static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy)
{
unsigned int ewma;
ewma = hctx->dispatch_busy;
if (!ewma && !busy)
return;
ewma *= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT - 1;
if (busy)
ewma += 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR;
ewma /= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT;
hctx->dispatch_busy = ewma;
}
#define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
static void blk_mq_handle_dev_resource(struct request *rq,
struct list_head *list)
{
struct request *next =
list_first_entry_or_null(list, struct request, queuelist);
/*
* If an I/O scheduler has been configured and we got a driver tag for
* the next request already, free it.
*/
if (next)
blk_mq_put_driver_tag(next);
list_add(&rq->queuelist, list);
__blk_mq_requeue_request(rq);
}
static void blk_mq_handle_zone_resource(struct request *rq,
struct list_head *zone_list)
{
/*
* If we end up here it is because we cannot dispatch a request to a
* specific zone due to LLD level zone-write locking or other zone
* related resource not being available. In this case, set the request
* aside in zone_list for retrying it later.
*/
list_add(&rq->queuelist, zone_list);
__blk_mq_requeue_request(rq);
}
enum prep_dispatch {
PREP_DISPATCH_OK,
PREP_DISPATCH_NO_TAG,
PREP_DISPATCH_NO_BUDGET,
};
static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
bool need_budget)
{
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
int budget_token = -1;
if (need_budget) {
budget_token = blk_mq_get_dispatch_budget(rq->q);
if (budget_token < 0) {
blk_mq_put_driver_tag(rq);
return PREP_DISPATCH_NO_BUDGET;
}
blk_mq_set_rq_budget_token(rq, budget_token);
}
if (!blk_mq_get_driver_tag(rq)) {
/*
* The initial allocation attempt failed, so we need to
* rerun the hardware queue when a tag is freed. The
* waitqueue takes care of that. If the queue is run
* before we add this entry back on the dispatch list,
* we'll re-run it below.
*/
if (!blk_mq_mark_tag_wait(hctx, rq)) {
/*
* All budgets not got from this function will be put
* together during handling partial dispatch
*/
if (need_budget)
blk_mq_put_dispatch_budget(rq->q, budget_token);
return PREP_DISPATCH_NO_TAG;
}
}
return PREP_DISPATCH_OK;
}
/* release all allocated budgets before calling to blk_mq_dispatch_rq_list */
static void blk_mq_release_budgets(struct request_queue *q,
struct list_head *list)
{
struct request *rq;
list_for_each_entry(rq, list, queuelist) {
int budget_token = blk_mq_get_rq_budget_token(rq);
if (budget_token >= 0)
blk_mq_put_dispatch_budget(q, budget_token);
}
}
/*
* Returns true if we did some work AND can potentially do more.
*/
bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
unsigned int nr_budgets)
{
enum prep_dispatch prep;
struct request_queue *q = hctx->queue;
struct request *rq, *nxt;
int errors, queued;
blk_status_t ret = BLK_STS_OK;
LIST_HEAD(zone_list);
bool needs_resource = false;
if (list_empty(list))
return false;
/*
* Now process all the entries, sending them to the driver.
*/
errors = queued = 0;
do {
struct blk_mq_queue_data bd;
rq = list_first_entry(list, struct request, queuelist);
WARN_ON_ONCE(hctx != rq->mq_hctx);
prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets);
if (prep != PREP_DISPATCH_OK)
break;
list_del_init(&rq->queuelist);
bd.rq = rq;
/*
* Flag last if we have no more requests, or if we have more
* but can't assign a driver tag to it.
*/
if (list_empty(list))
bd.last = true;
else {
nxt = list_first_entry(list, struct request, queuelist);
bd.last = !blk_mq_get_driver_tag(nxt);
}
/*
* once the request is queued to lld, no need to cover the
* budget any more
*/
if (nr_budgets)
nr_budgets--;
ret = q->mq_ops->queue_rq(hctx, &bd);
switch (ret) {
case BLK_STS_OK:
queued++;
break;
case BLK_STS_RESOURCE:
needs_resource = true;
fallthrough;
case BLK_STS_DEV_RESOURCE:
blk_mq_handle_dev_resource(rq, list);
goto out;
case BLK_STS_ZONE_RESOURCE:
/*
* Move the request to zone_list and keep going through
* the dispatch list to find more requests the drive can
* accept.
*/
blk_mq_handle_zone_resource(rq, &zone_list);
needs_resource = true;
break;
default:
errors++;
blk_mq_end_request(rq, ret);
}
} while (!list_empty(list));
out:
if (!list_empty(&zone_list))
list_splice_tail_init(&zone_list, list);
/* If we didn't flush the entire list, we could have told the driver
* there was more coming, but that turned out to be a lie.
*/
if ((!list_empty(list) || errors) && q->mq_ops->commit_rqs && queued)
q->mq_ops->commit_rqs(hctx);
/*
* Any items that need requeuing? Stuff them into hctx->dispatch,
* that is where we will continue on next queue run.
*/
if (!list_empty(list)) {
bool needs_restart;
/* For non-shared tags, the RESTART check will suffice */
bool no_tag = prep == PREP_DISPATCH_NO_TAG &&
(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED);
if (nr_budgets)
blk_mq_release_budgets(q, list);
spin_lock(&hctx->lock);
list_splice_tail_init(list, &hctx->dispatch);
spin_unlock(&hctx->lock);
/*
* Order adding requests to hctx->dispatch and checking
* SCHED_RESTART flag. The pair of this smp_mb() is the one
* in blk_mq_sched_restart(). Avoid restart code path to
* miss the new added requests to hctx->dispatch, meantime
* SCHED_RESTART is observed here.
*/
smp_mb();
/*
* If SCHED_RESTART was set by the caller of this function and
* it is no longer set that means that it was cleared by another
* thread and hence that a queue rerun is needed.
*
* If 'no_tag' is set, that means that we failed getting
* a driver tag with an I/O scheduler attached. If our dispatch
* waitqueue is no longer active, ensure that we run the queue
* AFTER adding our entries back to the list.
*
* If no I/O scheduler has been configured it is possible that
* the hardware queue got stopped and restarted before requests
* were pushed back onto the dispatch list. Rerun the queue to
* avoid starvation. Notes:
* - blk_mq_run_hw_queue() checks whether or not a queue has
* been stopped before rerunning a queue.
* - Some but not all block drivers stop a queue before
* returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
* and dm-rq.
*
* If driver returns BLK_STS_RESOURCE and SCHED_RESTART
* bit is set, run queue after a delay to avoid IO stalls
* that could otherwise occur if the queue is idle. We'll do
* similar if we couldn't get budget or couldn't lock a zone
* and SCHED_RESTART is set.
*/
needs_restart = blk_mq_sched_needs_restart(hctx);
if (prep == PREP_DISPATCH_NO_BUDGET)
needs_resource = true;
if (!needs_restart ||
(no_tag && list_empty_careful(&hctx->dispatch_wait.entry)))
blk_mq_run_hw_queue(hctx, true);
else if (needs_restart && needs_resource)
blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY);
blk_mq_update_dispatch_busy(hctx, true);
return false;
} else
blk_mq_update_dispatch_busy(hctx, false);
return (queued + errors) != 0;
}
/**
* __blk_mq_run_hw_queue - Run a hardware queue.
* @hctx: Pointer to the hardware queue to run.
*
* Send pending requests to the hardware.
*/
static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
{
/*
* We can't run the queue inline with ints disabled. Ensure that
* we catch bad users of this early.
*/
WARN_ON_ONCE(in_interrupt());
blk_mq_run_dispatch_ops(hctx->queue,
blk_mq_sched_dispatch_requests(hctx));
}
static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx)
{
int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask);
if (cpu >= nr_cpu_ids)
cpu = cpumask_first(hctx->cpumask);
return cpu;
}
/*
* It'd be great if the workqueue API had a way to pass
* in a mask and had some smarts for more clever placement.
* For now we just round-robin here, switching for every
* BLK_MQ_CPU_WORK_BATCH queued items.
*/
static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
{
bool tried = false;
int next_cpu = hctx->next_cpu;
if (hctx->queue->nr_hw_queues == 1)
return WORK_CPU_UNBOUND;
if (--hctx->next_cpu_batch <= 0) {
select_cpu:
next_cpu = cpumask_next_and(next_cpu, hctx->cpumask,
cpu_online_mask);
if (next_cpu >= nr_cpu_ids)
next_cpu = blk_mq_first_mapped_cpu(hctx);
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
}
/*
* Do unbound schedule if we can't find a online CPU for this hctx,
* and it should only happen in the path of handling CPU DEAD.
*/
if (!cpu_online(next_cpu)) {
if (!tried) {
tried = true;
goto select_cpu;
}
/*
* Make sure to re-select CPU next time once after CPUs
* in hctx->cpumask become online again.
*/
hctx->next_cpu = next_cpu;
hctx->next_cpu_batch = 1;
return WORK_CPU_UNBOUND;
}
hctx->next_cpu = next_cpu;
return next_cpu;
}
/**
* __blk_mq_delay_run_hw_queue - Run (or schedule to run) a hardware queue.
* @hctx: Pointer to the hardware queue to run.
* @async: If we want to run the queue asynchronously.
* @msecs: Milliseconds of delay to wait before running the queue.
*
* If !@async, try to run the queue now. Else, run the queue asynchronously and
* with a delay of @msecs.
*/
static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async,
unsigned long msecs)
{
if (unlikely(blk_mq_hctx_stopped(hctx)))
return;
if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
int cpu = get_cpu();
if (cpumask_test_cpu(cpu, hctx->cpumask)) {
__blk_mq_run_hw_queue(hctx);
put_cpu();
return;
}
put_cpu();
}
kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
msecs_to_jiffies(msecs));
}
/**
* blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously.
* @hctx: Pointer to the hardware queue to run.
* @msecs: Milliseconds of delay to wait before running the queue.
*
* Run a hardware queue asynchronously with a delay of @msecs.
*/
void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
{
__blk_mq_delay_run_hw_queue(hctx, true, msecs);
}
EXPORT_SYMBOL(blk_mq_delay_run_hw_queue);
/**
* blk_mq_run_hw_queue - Start to run a hardware queue.
* @hctx: Pointer to the hardware queue to run.
* @async: If we want to run the queue asynchronously.
*
* Check if the request queue is not in a quiesced state and if there are
* pending requests to be sent. If this is true, run the queue to send requests
* to hardware.
*/
void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
{
bool need_run;
/*
* When queue is quiesced, we may be switching io scheduler, or
* updating nr_hw_queues, or other things, and we can't run queue
* any more, even __blk_mq_hctx_has_pending() can't be called safely.
*
* And queue will be rerun in blk_mq_unquiesce_queue() if it is
* quiesced.
*/
__blk_mq_run_dispatch_ops(hctx->queue, false,
need_run = !blk_queue_quiesced(hctx->queue) &&
blk_mq_hctx_has_pending(hctx));
if (need_run)
__blk_mq_delay_run_hw_queue(hctx, async, 0);
}
EXPORT_SYMBOL(blk_mq_run_hw_queue);
/*
* Is the request queue handled by an IO scheduler that does not respect
* hardware queues when dispatching?
*/
static bool blk_mq_has_sqsched(struct request_queue *q)
{
struct elevator_queue *e = q->elevator;
if (e && e->type->ops.dispatch_request &&
!(e->type->elevator_features & ELEVATOR_F_MQ_AWARE))
return true;
return false;
}
/*
* Return prefered queue to dispatch from (if any) for non-mq aware IO
* scheduler.
*/
static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
/*
* If the IO scheduler does not respect hardware queues when
* dispatching, we just don't bother with multiple HW queues and
* dispatch from hctx for the current CPU since running multiple queues
* just causes lock contention inside the scheduler and pointless cache
* bouncing.
*/
hctx = blk_mq_map_queue_type(q, HCTX_TYPE_DEFAULT,
raw_smp_processor_id());
if (!blk_mq_hctx_stopped(hctx))
return hctx;
return NULL;
}
/**
* blk_mq_run_hw_queues - Run all hardware queues in a request queue.
* @q: Pointer to the request queue to run.
* @async: If we want to run the queue asynchronously.
*/
void blk_mq_run_hw_queues(struct request_queue *q, bool async)
{
struct blk_mq_hw_ctx *hctx, *sq_hctx;
int i;
sq_hctx = NULL;
if (blk_mq_has_sqsched(q))
sq_hctx = blk_mq_get_sq_hctx(q);
queue_for_each_hw_ctx(q, hctx, i) {
if (blk_mq_hctx_stopped(hctx))
continue;
/*
* Dispatch from this hctx either if there's no hctx preferred
* by IO scheduler or if it has requests that bypass the
* scheduler.
*/
if (!sq_hctx || sq_hctx == hctx ||
!list_empty_careful(&hctx->dispatch))
blk_mq_run_hw_queue(hctx, async);
}
}
EXPORT_SYMBOL(blk_mq_run_hw_queues);
/**
* blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously.
* @q: Pointer to the request queue to run.
* @msecs: Milliseconds of delay to wait before running the queues.
*/
void blk_mq_delay_run_hw_queues(struct request_queue *q, unsigned long msecs)
{
struct blk_mq_hw_ctx *hctx, *sq_hctx;
int i;
sq_hctx = NULL;
if (blk_mq_has_sqsched(q))
sq_hctx = blk_mq_get_sq_hctx(q);
queue_for_each_hw_ctx(q, hctx, i) {
if (blk_mq_hctx_stopped(hctx))
continue;
/*
* Dispatch from this hctx either if there's no hctx preferred
* by IO scheduler or if it has requests that bypass the
* scheduler.
*/
if (!sq_hctx || sq_hctx == hctx ||
!list_empty_careful(&hctx->dispatch))
blk_mq_delay_run_hw_queue(hctx, msecs);
}
}
EXPORT_SYMBOL(blk_mq_delay_run_hw_queues);
/**
* blk_mq_queue_stopped() - check whether one or more hctxs have been stopped
* @q: request queue.
*
* The caller is responsible for serializing this function against
* blk_mq_{start,stop}_hw_queue().
*/
bool blk_mq_queue_stopped(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
int i;
queue_for_each_hw_ctx(q, hctx, i)
if (blk_mq_hctx_stopped(hctx))
return true;
return false;
}
EXPORT_SYMBOL(blk_mq_queue_stopped);
/*
* This function is often used for pausing .queue_rq() by driver when
* there isn't enough resource or some conditions aren't satisfied, and
* BLK_STS_RESOURCE is usually returned.
*
* We do not guarantee that dispatch can be drained or blocked
* after blk_mq_stop_hw_queue() returns. Please use
* blk_mq_quiesce_queue() for that requirement.
*/
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
{
cancel_delayed_work(&hctx->run_work);
set_bit(BLK_MQ_S_STOPPED, &hctx->state);
}
EXPORT_SYMBOL(blk_mq_stop_hw_queue);
/*
* This function is often used for pausing .queue_rq() by driver when
* there isn't enough resource or some conditions aren't satisfied, and
* BLK_STS_RESOURCE is usually returned.
*
* We do not guarantee that dispatch can be drained or blocked
* after blk_mq_stop_hw_queues() returns. Please use
* blk_mq_quiesce_queue() for that requirement.
*/
void blk_mq_stop_hw_queues(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
int i;
queue_for_each_hw_ctx(q, hctx, i)
blk_mq_stop_hw_queue(hctx);
}
EXPORT_SYMBOL(blk_mq_stop_hw_queues);
void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
{
clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
blk_mq_run_hw_queue(hctx, false);
}
EXPORT_SYMBOL(blk_mq_start_hw_queue);
void blk_mq_start_hw_queues(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
int i;
queue_for_each_hw_ctx(q, hctx, i)
blk_mq_start_hw_queue(hctx);
}
EXPORT_SYMBOL(blk_mq_start_hw_queues);
void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
{
if (!blk_mq_hctx_stopped(hctx))
return;
clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
blk_mq_run_hw_queue(hctx, async);
}
EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue);
void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
{
struct blk_mq_hw_ctx *hctx;
int i;
queue_for_each_hw_ctx(q, hctx, i)
blk_mq_start_stopped_hw_queue(hctx, async);
}
EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
static void blk_mq_run_work_fn(struct work_struct *work)
{
struct blk_mq_hw_ctx *hctx;
hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work);
/*
* If we are stopped, don't run the queue.
*/
if (blk_mq_hctx_stopped(hctx))
return;
__blk_mq_run_hw_queue(hctx);
}
static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx,
struct request *rq,
bool at_head)
{
struct blk_mq_ctx *ctx = rq->mq_ctx;
enum hctx_type type = hctx->type;
lockdep_assert_held(&ctx->lock);
trace_block_rq_insert(rq);
if (at_head)
list_add(&rq->queuelist, &ctx->rq_lists[type]);
else
list_add_tail(&rq->queuelist, &ctx->rq_lists[type]);
}
void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
bool at_head)
{
struct blk_mq_ctx *ctx = rq->mq_ctx;
lockdep_assert_held(&ctx->lock);
__blk_mq_insert_req_list(hctx, rq, at_head);
blk_mq_hctx_mark_pending(hctx, ctx);
}
/**
* blk_mq_request_bypass_insert - Insert a request at dispatch list.
* @rq: Pointer to request to be inserted.
* @at_head: true if the request should be inserted at the head of the list.
* @run_queue: If we should run the hardware queue after inserting the request.
*
* Should only be used carefully, when the caller knows we want to
* bypass a potential IO scheduler on the target device.
*/
void blk_mq_request_bypass_insert(struct request *rq, bool at_head,
bool run_queue)
{
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
spin_lock(&hctx->lock);
if (at_head)
list_add(&rq->queuelist, &hctx->dispatch);
else
list_add_tail(&rq->queuelist, &hctx->dispatch);
spin_unlock(&hctx->lock);
if (run_queue)
blk_mq_run_hw_queue(hctx, false);
}
void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
struct list_head *list)
{
struct request *rq;
enum hctx_type type = hctx->type;
/*
* preemption doesn't flush plug list, so it's possible ctx->cpu is
* offline now
*/
list_for_each_entry(rq, list, queuelist) {
BUG_ON(rq->mq_ctx != ctx);
trace_block_rq_insert(rq);
}
spin_lock(&ctx->lock);
list_splice_tail_init(list, &ctx->rq_lists[type]);
blk_mq_hctx_mark_pending(hctx, ctx);
spin_unlock(&ctx->lock);
}
static void blk_mq_commit_rqs(struct blk_mq_hw_ctx *hctx, int *queued,
bool from_schedule)
{
if (hctx->queue->mq_ops->commit_rqs) {
trace_block_unplug(hctx->queue, *queued, !from_schedule);
hctx->queue->mq_ops->commit_rqs(hctx);
}
*queued = 0;
}
static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,
unsigned int nr_segs)
{
int err;
if (bio->bi_opf & REQ_RAHEAD)
rq->cmd_flags |= REQ_FAILFAST_MASK;
rq->__sector = bio->bi_iter.bi_sector;
rq->write_hint = bio->bi_write_hint;
blk_rq_bio_prep(rq, bio, nr_segs);
/* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */
err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO);
WARN_ON_ONCE(err);
blk_account_io_start(rq);
}
static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
struct request *rq, bool last)
{
struct request_queue *q = rq->q;
struct blk_mq_queue_data bd = {
.rq = rq,
.last = last,
};
blk_status_t ret;
/*
* For OK queue, we are done. For error, caller may kill it.
* Any other error (busy), just add it to our list as we
* previously would have done.
*/
ret = q->mq_ops->queue_rq(hctx, &bd);
switch (ret) {
case BLK_STS_OK:
blk_mq_update_dispatch_busy(hctx, false);
break;
case BLK_STS_RESOURCE:
case BLK_STS_DEV_RESOURCE:
blk_mq_update_dispatch_busy(hctx, true);
__blk_mq_requeue_request(rq);
break;
default:
blk_mq_update_dispatch_busy(hctx, false);
break;
}
return ret;
}
static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
struct request *rq,
bool bypass_insert, bool last)
{
struct request_queue *q = rq->q;
bool run_queue = true;
int budget_token;
/*
* RCU or SRCU read lock is needed before checking quiesced flag.
*
* When queue is stopped or quiesced, ignore 'bypass_insert' from
* blk_mq_request_issue_directly(), and return BLK_STS_OK to caller,
* and avoid driver to try to dispatch again.
*/
if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) {
run_queue = false;
bypass_insert = false;
goto insert;
}
if ((rq->rq_flags & RQF_ELV) && !bypass_insert)
goto insert;
budget_token = blk_mq_get_dispatch_budget(q);
if (budget_token < 0)
goto insert;
blk_mq_set_rq_budget_token(rq, budget_token);
if (!blk_mq_get_driver_tag(rq)) {
blk_mq_put_dispatch_budget(q, budget_token);
goto insert;
}
return __blk_mq_issue_directly(hctx, rq, last);
insert:
if (bypass_insert)
return BLK_STS_RESOURCE;
blk_mq_sched_insert_request(rq, false, run_queue, false);
return BLK_STS_OK;
}
/**
* blk_mq_try_issue_directly - Try to send a request directly to device driver.
* @hctx: Pointer of the associated hardware queue.
* @rq: Pointer to request to be sent.
*
* If the device has enough resources to accept a new request now, send the
* request directly to device driver. Else, insert at hctx->dispatch queue, so
* we can try send it another time in the future. Requests inserted at this
* queue have higher priority.
*/
static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
struct request *rq)
{
blk_status_t ret =
__blk_mq_try_issue_directly(hctx, rq, false, true);
if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE)
blk_mq_request_bypass_insert(rq, false, true);
else if (ret != BLK_STS_OK)
blk_mq_end_request(rq, ret);
}
static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
{
return __blk_mq_try_issue_directly(rq->mq_hctx, rq, true, last);
}
static void blk_mq_plug_issue_direct(struct blk_plug *plug, bool from_schedule)
{
struct blk_mq_hw_ctx *hctx = NULL;
struct request *rq;
int queued = 0;
int errors = 0;
while ((rq = rq_list_pop(&plug->mq_list))) {
bool last = rq_list_empty(plug->mq_list);
blk_status_t ret;
if (hctx != rq->mq_hctx) {
if (hctx)
blk_mq_commit_rqs(hctx, &queued, from_schedule);
hctx = rq->mq_hctx;
}
ret = blk_mq_request_issue_directly(rq, last);
switch (ret) {
case BLK_STS_OK:
queued++;
break;
case BLK_STS_RESOURCE:
case BLK_STS_DEV_RESOURCE:
blk_mq_request_bypass_insert(rq, false, last);
blk_mq_commit_rqs(hctx, &queued, from_schedule);
return;
default:
blk_mq_end_request(rq, ret);
errors++;
break;
}
}
/*
* If we didn't flush the entire list, we could have told the driver
* there was more coming, but that turned out to be a lie.
*/
if (errors)
blk_mq_commit_rqs(hctx, &queued, from_schedule);
}
static void __blk_mq_flush_plug_list(struct request_queue *q,
struct blk_plug *plug)
{
if (blk_queue_quiesced(q))
return;
q->mq_ops->queue_rqs(&plug->mq_list);
}
static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched)
{
struct blk_mq_hw_ctx *this_hctx = NULL;
struct blk_mq_ctx *this_ctx = NULL;
struct request *requeue_list = NULL;
unsigned int depth = 0;
LIST_HEAD(list);
do {
struct request *rq = rq_list_pop(&plug->mq_list);
if (!this_hctx) {
this_hctx = rq->mq_hctx;
this_ctx = rq->mq_ctx;
} else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx) {
rq_list_add(&requeue_list, rq);
continue;
}
list_add_tail(&rq->queuelist, &list);
depth++;
} while (!rq_list_empty(plug->mq_list));
plug->mq_list = requeue_list;
trace_block_unplug(this_hctx->queue, depth, !from_sched);
blk_mq_sched_insert_requests(this_hctx, this_ctx, &list, from_sched);
}
void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
{
struct request *rq;
if (rq_list_empty(plug->mq_list))
return;
plug->rq_count = 0;
if (!plug->multiple_queues && !plug->has_elevator && !from_schedule) {
struct request_queue *q;
rq = rq_list_peek(&plug->mq_list);
q = rq->q;
/*
* Peek first request and see if we have a ->queue_rqs() hook.
* If we do, we can dispatch the whole plug list in one go. We
* already know at this point that all requests belong to the
* same queue, caller must ensure that's the case.
*
* Since we pass off the full list to the driver at this point,
* we do not increment the active request count for the queue.
* Bypass shared tags for now because of that.
*/
if (q->mq_ops->queue_rqs &&
!(rq->mq_hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
blk_mq_run_dispatch_ops(q,
__blk_mq_flush_plug_list(q, plug));
if (rq_list_empty(plug->mq_list))
return;
}
blk_mq_run_dispatch_ops(q,
blk_mq_plug_issue_direct(plug, false));
if (rq_list_empty(plug->mq_list))
return;
}
do {
blk_mq_dispatch_plug_list(plug, from_schedule);
} while (!rq_list_empty(plug->mq_list));
}
void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
struct list_head *list)
{
int queued = 0;
int errors = 0;
while (!list_empty(list)) {
blk_status_t ret;
struct request *rq = list_first_entry(list, struct request,
queuelist);
list_del_init(&rq->queuelist);
ret = blk_mq_request_issue_directly(rq, list_empty(list));
if (ret != BLK_STS_OK) {
if (ret == BLK_STS_RESOURCE ||
ret == BLK_STS_DEV_RESOURCE) {
blk_mq_request_bypass_insert(rq, false,
list_empty(list));
break;
}
blk_mq_end_request(rq, ret);
errors++;
} else
queued++;
}
/*
* If we didn't flush the entire list, we could have told
* the driver there was more coming, but that turned out to
* be a lie.
*/
if ((!list_empty(list) || errors) &&
hctx->queue->mq_ops->commit_rqs && queued)
hctx->queue->mq_ops->commit_rqs(hctx);
}
/*
* Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple
* queues. This is important for md arrays to benefit from merging
* requests.
*/
static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug)
{
if (plug->multiple_queues)
return BLK_MAX_REQUEST_COUNT * 2;
return BLK_MAX_REQUEST_COUNT;
}
static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq)
{
struct request *last = rq_list_peek(&plug->mq_list);
if (!plug->rq_count) {
trace_block_plug(rq->q);
} else if (plug->rq_count >= blk_plug_max_rq_count(plug) ||
(!blk_queue_nomerges(rq->q) &&
blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
blk_mq_flush_plug_list(plug, false);
trace_block_plug(rq->q);
}
if (!plug->multiple_queues && last && last->q != rq->q)
plug->multiple_queues = true;
if (!plug->has_elevator && (rq->rq_flags & RQF_ELV))
plug->has_elevator = true;
rq->rq_next = NULL;
rq_list_add(&plug->mq_list, rq);
plug->rq_count++;
}
static bool blk_mq_attempt_bio_merge(struct request_queue *q,
struct bio *bio, unsigned int nr_segs)
{
if (!blk_queue_nomerges(q) && bio_mergeable(bio)) {
if (blk_attempt_plug_merge(q, bio, nr_segs))
return true;
if (blk_mq_sched_bio_merge(q, bio, nr_segs))
return true;
}
return false;
}
static struct request *blk_mq_get_new_requests(struct request_queue *q,
struct blk_plug *plug,
struct bio *bio,
unsigned int nsegs)
{
struct blk_mq_alloc_data data = {
.q = q,
.nr_tags = 1,
.cmd_flags = bio->bi_opf,
};
struct request *rq;
if (unlikely(bio_queue_enter(bio)))
return NULL;
if (blk_mq_attempt_bio_merge(q, bio, nsegs))
goto queue_exit;
rq_qos_throttle(q, bio);
if (plug) {
data.nr_tags = plug->nr_ios;
plug->nr_ios = 1;
data.cached_rq = &plug->cached_rq;
}
rq = __blk_mq_alloc_requests(&data);
if (rq)
return rq;
rq_qos_cleanup(q, bio);
if (bio->bi_opf & REQ_NOWAIT)
bio_wouldblock_error(bio);
queue_exit:
blk_queue_exit(q);
return NULL;
}
static inline struct request *blk_mq_get_cached_request(struct request_queue *q,
struct blk_plug *plug, struct bio **bio, unsigned int nsegs)
{
struct request *rq;
if (!plug)
return NULL;
rq = rq_list_peek(&plug->cached_rq);
if (!rq || rq->q != q)
return NULL;
if (blk_mq_attempt_bio_merge(q, *bio, nsegs)) {
*bio = NULL;
return NULL;
}
rq_qos_throttle(q, *bio);
if (blk_mq_get_hctx_type((*bio)->bi_opf) != rq->mq_hctx->type)
return NULL;
if (op_is_flush(rq->cmd_flags) != op_is_flush((*bio)->bi_opf))
return NULL;
rq->cmd_flags = (*bio)->bi_opf;
plug->cached_rq = rq_list_next(rq);
INIT_LIST_HEAD(&rq->queuelist);
return rq;
}
/**
* blk_mq_submit_bio - Create and send a request to block device.
* @bio: Bio pointer.
*
* Builds up a request structure from @q and @bio and send to the device. The
* request may not be queued directly to hardware if:
* * This request can be merged with another one
* * We want to place request at plug queue for possible future merging
* * There is an IO scheduler active at this queue
*
* It will not queue the request if there is an error with the bio, or at the
* request creation.
*/
void blk_mq_submit_bio(struct bio *bio)
{
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
struct blk_plug *plug = blk_mq_plug(q, bio);
const int is_sync = op_is_sync(bio->bi_opf);
struct request *rq;
unsigned int nr_segs = 1;
blk_status_t ret;
if (unlikely(!blk_crypto_bio_prep(&bio)))
return;
blk_queue_bounce(q, &bio);
if (blk_may_split(q, bio))
__blk_queue_split(q, &bio, &nr_segs);
if (!bio_integrity_prep(bio))
return;
rq = blk_mq_get_cached_request(q, plug, &bio, nr_segs);
if (!rq) {
if (!bio)
return;
rq = blk_mq_get_new_requests(q, plug, bio, nr_segs);
if (unlikely(!rq))
return;
}
trace_block_getrq(bio);
rq_qos_track(q, rq, bio);
blk_mq_bio_to_request(rq, bio, nr_segs);
ret = blk_crypto_init_request(rq);
if (ret != BLK_STS_OK) {
bio->bi_status = ret;
bio_endio(bio);
blk_mq_free_request(rq);
return;
}
if (op_is_flush(bio->bi_opf)) {
blk_insert_flush(rq);
return;
}
if (plug)
blk_add_rq_to_plug(plug, rq);
else if ((rq->rq_flags & RQF_ELV) ||
(rq->mq_hctx->dispatch_busy &&
(q->nr_hw_queues == 1 || !is_sync)))
blk_mq_sched_insert_request(rq, false, true, true);
else
blk_mq_run_dispatch_ops(rq->q,
blk_mq_try_issue_directly(rq->mq_hctx, rq));
}
/**
* blk_cloned_rq_check_limits - Helper function to check a cloned request
* for the new queue limits
* @q: the queue
* @rq: the request being checked
*
* Description:
* @rq may have been made based on weaker limitations of upper-level queues
* in request stacking drivers, and it may violate the limitation of @q.
* Since the block layer and the underlying device driver trust @rq
* after it is inserted to @q, it should be checked against @q before
* the insertion using this generic function.
*
* Request stacking drivers like request-based dm may change the queue
* limits when retrying requests on other queues. Those requests need
* to be checked against the new queue limits again during dispatch.
*/
static blk_status_t blk_cloned_rq_check_limits(struct request_queue *q,
struct request *rq)
{
unsigned int max_sectors = blk_queue_get_max_sectors(q, req_op(rq));
if (blk_rq_sectors(rq) > max_sectors) {
/*
* SCSI device does not have a good way to return if
* Write Same/Zero is actually supported. If a device rejects
* a non-read/write command (discard, write same,etc.) the
* low-level device driver will set the relevant queue limit to
* 0 to prevent blk-lib from issuing more of the offending
* operations. Commands queued prior to the queue limit being
* reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
* errors being propagated to upper layers.
*/
if (max_sectors == 0)
return BLK_STS_NOTSUPP;
printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
__func__, blk_rq_sectors(rq), max_sectors);
return BLK_STS_IOERR;
}
/*
* The queue settings related to segment counting may differ from the
* original queue.
*/
rq->nr_phys_segments = blk_recalc_rq_segments(rq);
if (rq->nr_phys_segments > queue_max_segments(q)) {
printk(KERN_ERR "%s: over max segments limit. (%hu > %hu)\n",
__func__, rq->nr_phys_segments, queue_max_segments(q));
return BLK_STS_IOERR;
}
return BLK_STS_OK;
}
/**
* blk_insert_cloned_request - Helper for stacking drivers to submit a request
* @q: the queue to submit the request
* @rq: the request being queued
*/
blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *rq)
{
blk_status_t ret;
ret = blk_cloned_rq_check_limits(q, rq);
if (ret != BLK_STS_OK)
return ret;
if (rq->q->disk &&
should_fail_request(rq->q->disk->part0, blk_rq_bytes(rq)))
return BLK_STS_IOERR;
if (blk_crypto_insert_cloned_request(rq))
return BLK_STS_IOERR;
blk_account_io_start(rq);
/*
* Since we have a scheduler attached on the top device,
* bypass a potential scheduler on the bottom device for
* insert.
*/
blk_mq_run_dispatch_ops(rq->q,
ret = blk_mq_request_issue_directly(rq, true));
if (ret)
blk_account_io_done(rq, ktime_get_ns());
return ret;
}
EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
/**
* blk_rq_unprep_clone - Helper function to free all bios in a cloned request
* @rq: the clone request to be cleaned up
*
* Description:
* Free all bios in @rq for a cloned request.
*/
void blk_rq_unprep_clone(struct request *rq)
{
struct bio *bio;
while ((bio = rq->bio) != NULL) {
rq->bio = bio->bi_next;
bio_put(bio);
}
}
EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
/**
* blk_rq_prep_clone - Helper function to setup clone request
* @rq: the request to be setup
* @rq_src: original request to be cloned
* @bs: bio_set that bios for clone are allocated from
* @gfp_mask: memory allocation mask for bio
* @bio_ctr: setup function to be called for each clone bio.
* Returns %0 for success, non %0 for failure.
* @data: private data to be passed to @bio_ctr
*
* Description:
* Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
* Also, pages which the original bios are pointing to are not copied
* and the cloned bios just point same pages.
* So cloned bios must be completed before original bios, which means
* the caller must complete @rq before @rq_src.
*/
int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
struct bio_set *bs, gfp_t gfp_mask,
int (*bio_ctr)(struct bio *, struct bio *, void *),
void *data)
{
struct bio *bio, *bio_src;
if (!bs)
bs = &fs_bio_set;
__rq_for_each_bio(bio_src, rq_src) {
bio = bio_clone_fast(bio_src, gfp_mask, bs);
if (!bio)
goto free_and_out;
bio->bi_bdev = rq->q->disk->part0;
if (bio_ctr && bio_ctr(bio, bio_src, data))
goto free_and_out;
if (rq->bio) {
rq->biotail->bi_next = bio;
rq->biotail = bio;
} else {
rq->bio = rq->biotail = bio;
}
bio = NULL;
}
/* Copy attributes of the original request to the clone request. */
rq->__sector = blk_rq_pos(rq_src);
rq->__data_len = blk_rq_bytes(rq_src);
if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) {
rq->rq_flags |= RQF_SPECIAL_PAYLOAD;
rq->special_vec = rq_src->special_vec;
}
rq->nr_phys_segments = rq_src->nr_phys_segments;
rq->ioprio = rq_src->ioprio;
if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)
goto free_and_out;
return 0;
free_and_out:
if (bio)
bio_put(bio);
blk_rq_unprep_clone(rq);
return -ENOMEM;
}
EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
/*
* Steal bios from a request and add them to a bio list.
* The request must not have been partially completed before.
*/
void blk_steal_bios(struct bio_list *list, struct request *rq)
{
if (rq->bio) {
if (list->tail)
list->tail->bi_next = rq->bio;
else
list->head = rq->bio;
list->tail = rq->biotail;
rq->bio = NULL;
rq->biotail = NULL;
}
rq->__data_len = 0;
}
EXPORT_SYMBOL_GPL(blk_steal_bios);
static size_t order_to_size(unsigned int order)
{
return (size_t)PAGE_SIZE << order;
}
/* called before freeing request pool in @tags */
static void blk_mq_clear_rq_mapping(struct blk_mq_tags *drv_tags,
struct blk_mq_tags *tags)
{
struct page *page;
unsigned long flags;
/* There is no need to clear a driver tags own mapping */
if (drv_tags == tags)
return;
list_for_each_entry(page, &tags->page_list, lru) {
unsigned long start = (unsigned long)page_address(page);
unsigned long end = start + order_to_size(page->private);
int i;
for (i = 0; i < drv_tags->nr_tags; i++) {
struct request *rq = drv_tags->rqs[i];
unsigned long rq_addr = (unsigned long)rq;
if (rq_addr >= start && rq_addr < end) {
WARN_ON_ONCE(req_ref_read(rq) != 0);
cmpxchg(&drv_tags->rqs[i], rq, NULL);
}
}
}
/*
* Wait until all pending iteration is done.
*
* Request reference is cleared and it is guaranteed to be observed
* after the ->lock is released.
*/
spin_lock_irqsave(&drv_tags->lock, flags);
spin_unlock_irqrestore(&drv_tags->lock, flags);
}
void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
unsigned int hctx_idx)
{
struct blk_mq_tags *drv_tags;
struct page *page;
if (blk_mq_is_shared_tags(set->flags))
drv_tags = set->shared_tags;
else
drv_tags = set->tags[hctx_idx];
if (tags->static_rqs && set->ops->exit_request) {
int i;
for (i = 0; i < tags->nr_tags; i++) {
struct request *rq = tags->static_rqs[i];
if (!rq)
continue;
set->ops->exit_request(set, rq, hctx_idx);
tags->static_rqs[i] = NULL;
}
}
blk_mq_clear_rq_mapping(drv_tags, tags);
while (!list_empty(&tags->page_list)) {
page = list_first_entry(&tags->page_list, struct page, lru);
list_del_init(&page->lru);
/*
* Remove kmemleak object previously allocated in
* blk_mq_alloc_rqs().
*/
kmemleak_free(page_address(page));
__free_pages(page, page->private);
}
}
void blk_mq_free_rq_map(struct blk_mq_tags *tags)
{
kfree(tags->rqs);
tags->rqs = NULL;
kfree(tags->static_rqs);
tags->static_rqs = NULL;
blk_mq_free_tags(tags);
}
static struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
unsigned int hctx_idx,
unsigned int nr_tags,
unsigned int reserved_tags)
{
struct blk_mq_tags *tags;
int node;
node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], hctx_idx);
if (node == NUMA_NO_NODE)
node = set->numa_node;
tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
if (!tags)
return NULL;
tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *),
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
node);
if (!tags->rqs) {
blk_mq_free_tags(tags);
return NULL;
}
tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *),
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
node);
if (!tags->static_rqs) {
kfree(tags->rqs);
blk_mq_free_tags(tags);
return NULL;
}
return tags;
}
static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
unsigned int hctx_idx, int node)
{
int ret;
if (set->ops->init_request) {
ret = set->ops->init_request(set, rq, hctx_idx, node);
if (ret)
return ret;
}
WRITE_ONCE(rq->state, MQ_RQ_IDLE);
return 0;
}
static int blk_mq_alloc_rqs(struct blk_mq_tag_set *set,
struct blk_mq_tags *tags,
unsigned int hctx_idx, unsigned int depth)
{
unsigned int i, j, entries_per_page, max_order = 4;
size_t rq_size, left;
int node;
node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], hctx_idx);
if (node == NUMA_NO_NODE)
node = set->numa_node;
INIT_LIST_HEAD(&tags->page_list);
/*
* rq_size is the size of the request plus driver payload, rounded
* to the cacheline size
*/
rq_size = round_up(sizeof(struct request) + set->cmd_size,
cache_line_size());
left = rq_size * depth;
for (i = 0; i < depth; ) {
int this_order = max_order;
struct page *page;
int to_do;
void *p;
while (this_order && left < order_to_size(this_order - 1))
this_order--;
do {
page = alloc_pages_node(node,
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO,
this_order);
if (page)
break;
if (!this_order--)
break;
if (order_to_size(this_order) < rq_size)
break;
} while (1);
if (!page)
goto fail;
page->private = this_order;
list_add_tail(&page->lru, &tags->page_list);
p = page_address(page);
/*
* Allow kmemleak to scan these pages as they contain pointers
* to additional allocations like via ops->init_request().
*/
kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO);
entries_per_page = order_to_size(this_order) / rq_size;
to_do = min(entries_per_page, depth - i);
left -= to_do * rq_size;
for (j = 0; j < to_do; j++) {
struct request *rq = p;
tags->static_rqs[i] = rq;
if (blk_mq_init_request(set, rq, hctx_idx, node)) {
tags->static_rqs[i] = NULL;
goto fail;
}
p += rq_size;
i++;
}
}
return 0;
fail:
blk_mq_free_rqs(set, tags, hctx_idx);
return -ENOMEM;
}
struct rq_iter_data {
struct blk_mq_hw_ctx *hctx;
bool has_rq;
};
static bool blk_mq_has_request(struct request *rq, void *data, bool reserved)
{
struct rq_iter_data *iter_data = data;
if (rq->mq_hctx != iter_data->hctx)
return true;
iter_data->has_rq = true;
return false;
}
static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx *hctx)
{
struct blk_mq_tags *tags = hctx->sched_tags ?
hctx->sched_tags : hctx->tags;
struct rq_iter_data data = {
.hctx = hctx,
};
blk_mq_all_tag_iter(tags, blk_mq_has_request, &data);
return data.has_rq;
}
static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu,
struct blk_mq_hw_ctx *hctx)
{
if (cpumask_first_and(hctx->cpumask, cpu_online_mask) != cpu)
return false;
if (cpumask_next_and(cpu, hctx->cpumask, cpu_online_mask) < nr_cpu_ids)
return false;
return true;
}
static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node)
{
struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
struct blk_mq_hw_ctx, cpuhp_online);
if (!cpumask_test_cpu(cpu, hctx->cpumask) ||
!blk_mq_last_cpu_in_hctx(cpu, hctx))
return 0;
/*
* Prevent new request from being allocated on the current hctx.
*
* The smp_mb__after_atomic() Pairs with the implied barrier in
* test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is
* seen once we return from the tag allocator.
*/
set_bit(BLK_MQ_S_INACTIVE, &hctx->state);
smp_mb__after_atomic();
/*
* Try to grab a reference to the queue and wait for any outstanding
* requests. If we could not grab a reference the queue has been
* frozen and there are no requests.
*/
if (percpu_ref_tryget(&hctx->queue->q_usage_counter)) {
while (blk_mq_hctx_has_requests(hctx))
msleep(5);
percpu_ref_put(&hctx->queue->q_usage_counter);
}
return 0;
}
static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node)
{
struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
struct blk_mq_hw_ctx, cpuhp_online);
if (cpumask_test_cpu(cpu, hctx->cpumask))
clear_bit(BLK_MQ_S_INACTIVE, &hctx->state);
return 0;
}
/*
* 'cpu' is going away. splice any existing rq_list entries from this
* software queue to the hw queue dispatch list, and ensure that it
* gets run.
*/
static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
{
struct blk_mq_hw_ctx *hctx;
struct blk_mq_ctx *ctx;
LIST_HEAD(tmp);
enum hctx_type type;
hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
if (!cpumask_test_cpu(cpu, hctx->cpumask))
return 0;
ctx = __blk_mq_get_ctx(hctx->queue, cpu);
type = hctx->type;
spin_lock(&ctx->lock);
if (!list_empty(&ctx->rq_lists[type])) {
list_splice_init(&ctx->rq_lists[type], &tmp);
blk_mq_hctx_clear_pending(hctx, ctx);
}
spin_unlock(&ctx->lock);
if (list_empty(&tmp))
return 0;
spin_lock(&hctx->lock);
list_splice_tail_init(&tmp, &hctx->dispatch);
spin_unlock(&hctx->lock);
blk_mq_run_hw_queue(hctx, true);
return 0;
}
static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx)
{
if (!(hctx->flags & BLK_MQ_F_STACKING))
cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
&hctx->cpuhp_online);
cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD,
&hctx->cpuhp_dead);
}
/*
* Before freeing hw queue, clearing the flush request reference in
* tags->rqs[] for avoiding potential UAF.
*/
static void blk_mq_clear_flush_rq_mapping(struct blk_mq_tags *tags,
unsigned int queue_depth, struct request *flush_rq)
{
int i;
unsigned long flags;
/* The hw queue may not be mapped yet */
if (!tags)
return;
WARN_ON_ONCE(req_ref_read(flush_rq) != 0);
for (i = 0; i < queue_depth; i++)
cmpxchg(&tags->rqs[i], flush_rq, NULL);
/*
* Wait until all pending iteration is done.
*
* Request reference is cleared and it is guaranteed to be observed
* after the ->lock is released.
*/
spin_lock_irqsave(&tags->lock, flags);
spin_unlock_irqrestore(&tags->lock, flags);
}
/* hctx->ctxs will be freed in queue's release handler */
static void blk_mq_exit_hctx(struct request_queue *q,
struct blk_mq_tag_set *set,
struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
{
struct request *flush_rq = hctx->fq->flush_rq;
if (blk_mq_hw_queue_mapped(hctx))
blk_mq_tag_idle(hctx);
blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx],
set->queue_depth, flush_rq);
if (set->ops->exit_request)
set->ops->exit_request(set, flush_rq, hctx_idx);
if (set->ops->exit_hctx)
set->ops->exit_hctx(hctx, hctx_idx);
blk_mq_remove_cpuhp(hctx);
spin_lock(&q->unused_hctx_lock);
list_add(&hctx->hctx_list, &q->unused_hctx_list);
spin_unlock(&q->unused_hctx_lock);
}
static void blk_mq_exit_hw_queues(struct request_queue *q,
struct blk_mq_tag_set *set, int nr_queue)
{
struct blk_mq_hw_ctx *hctx;
unsigned int i;
queue_for_each_hw_ctx(q, hctx, i) {
if (i == nr_queue)
break;
blk_mq_debugfs_unregister_hctx(hctx);
blk_mq_exit_hctx(q, set, hctx, i);
}
}
static int blk_mq_init_hctx(struct request_queue *q,
struct blk_mq_tag_set *set,
struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
{
hctx->queue_num = hctx_idx;
if (!(hctx->flags & BLK_MQ_F_STACKING))
cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
&hctx->cpuhp_online);
cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);
hctx->tags = set->tags[hctx_idx];
if (set->ops->init_hctx &&
set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
goto unregister_cpu_notifier;
if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx,
hctx->numa_node))
goto exit_hctx;
return 0;
exit_hctx:
if (set->ops->exit_hctx)
set->ops->exit_hctx(hctx, hctx_idx);
unregister_cpu_notifier:
blk_mq_remove_cpuhp(hctx);
return -1;
}
static struct blk_mq_hw_ctx *
blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set,
int node)
{
struct blk_mq_hw_ctx *hctx;
gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY;
hctx = kzalloc_node(sizeof(struct blk_mq_hw_ctx), gfp, node);
if (!hctx)
goto fail_alloc_hctx;
if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node))
goto free_hctx;
atomic_set(&hctx->nr_active, 0);
if (node == NUMA_NO_NODE)
node = set->numa_node;
hctx->numa_node = node;
INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
spin_lock_init(&hctx->lock);
INIT_LIST_HEAD(&hctx->dispatch);
hctx->queue = q;
hctx->flags = set->flags & ~BLK_MQ_F_TAG_QUEUE_SHARED;
INIT_LIST_HEAD(&hctx->hctx_list);
/*
* Allocate space for all possible cpus to avoid allocation at
* runtime
*/
hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *),
gfp, node);
if (!hctx->ctxs)
goto free_cpumask;
if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8),
gfp, node, false, false))
goto free_ctxs;
hctx->nr_ctx = 0;
spin_lock_init(&hctx->dispatch_wait_lock);
init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake);
INIT_LIST_HEAD(&hctx->dispatch_wait.entry);
hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp);
if (!hctx->fq)
goto free_bitmap;
blk_mq_hctx_kobj_init(hctx);
return hctx;
free_bitmap:
sbitmap_free(&hctx->ctx_map);
free_ctxs:
kfree(hctx->ctxs);
free_cpumask:
free_cpumask_var(hctx->cpumask);
free_hctx:
kfree(hctx);
fail_alloc_hctx:
return NULL;
}
static void blk_mq_init_cpu_queues(struct request_queue *q,
unsigned int nr_hw_queues)
{
struct blk_mq_tag_set *set = q->tag_set;
unsigned int i, j;
for_each_possible_cpu(i) {
struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
struct blk_mq_hw_ctx *hctx;
int k;
__ctx->cpu = i;
spin_lock_init(&__ctx->lock);
for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++)
INIT_LIST_HEAD(&__ctx->rq_lists[k]);
__ctx->queue = q;
/*
* Set local node, IFF we have more than one hw queue. If
* not, we remain on the home node of the device
*/
for (j = 0; j < set->nr_maps; j++) {
hctx = blk_mq_map_queue_type(q, j, i);
if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
hctx->numa_node = cpu_to_node(i);
}
}
}
struct blk_mq_tags *blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
unsigned int hctx_idx,
unsigned int depth)
{
struct blk_mq_tags *tags;
int ret;
tags = blk_mq_alloc_rq_map(set, hctx_idx, depth, set->reserved_tags);
if (!tags)
return NULL;
ret = blk_mq_alloc_rqs(set, tags, hctx_idx, depth);
if (ret) {
blk_mq_free_rq_map(tags);
return NULL;
}
return tags;
}
static bool __blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
int hctx_idx)
{
if (blk_mq_is_shared_tags(set->flags)) {
set->tags[hctx_idx] = set->shared_tags;
return true;
}
set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs(set, hctx_idx,
set->queue_depth);
return set->tags[hctx_idx];
}
void blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
struct blk_mq_tags *tags,
unsigned int hctx_idx)
{
if (tags) {
blk_mq_free_rqs(set, tags, hctx_idx);
blk_mq_free_rq_map(tags);
}
}
static void __blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
unsigned int hctx_idx)
{
if (!blk_mq_is_shared_tags(set->flags))
blk_mq_free_map_and_rqs(set, set->tags[hctx_idx], hctx_idx);
set->tags[hctx_idx] = NULL;
}
static void blk_mq_map_swqueue(struct request_queue *q)
{
unsigned int i, j, hctx_idx;
struct blk_mq_hw_ctx *hctx;
struct blk_mq_ctx *ctx;
struct blk_mq_tag_set *set = q->tag_set;
queue_for_each_hw_ctx(q, hctx, i) {
cpumask_clear(hctx->cpumask);
hctx->nr_ctx = 0;
hctx->dispatch_from = NULL;
}
/*
* Map software to hardware queues.
*
* If the cpu isn't present, the cpu is mapped to first hctx.
*/
for_each_possible_cpu(i) {
ctx = per_cpu_ptr(q->queue_ctx, i);
for (j = 0; j < set->nr_maps; j++) {
if (!set->map[j].nr_queues) {
ctx->hctxs[j] = blk_mq_map_queue_type(q,
HCTX_TYPE_DEFAULT, i);
continue;
}
hctx_idx = set->map[j].mq_map[i];
/* unmapped hw queue can be remapped after CPU topo changed */
if (!set->tags[hctx_idx] &&
!__blk_mq_alloc_map_and_rqs(set, hctx_idx)) {
/*
* If tags initialization fail for some hctx,
* that hctx won't be brought online. In this
* case, remap the current ctx to hctx[0] which
* is guaranteed to always have tags allocated
*/
set->map[j].mq_map[i] = 0;
}
hctx = blk_mq_map_queue_type(q, j, i);
ctx->hctxs[j] = hctx;
/*
* If the CPU is already set in the mask, then we've
* mapped this one already. This can happen if
* devices share queues across queue maps.
*/
if (cpumask_test_cpu(i, hctx->cpumask))
continue;
cpumask_set_cpu(i, hctx->cpumask);
hctx->type = j;
ctx->index_hw[hctx->type] = hctx->nr_ctx;
hctx->ctxs[hctx->nr_ctx++] = ctx;
/*
* If the nr_ctx type overflows, we have exceeded the
* amount of sw queues we can support.
*/
BUG_ON(!hctx->nr_ctx);
}
for (; j < HCTX_MAX_TYPES; j++)
ctx->hctxs[j] = blk_mq_map_queue_type(q,
HCTX_TYPE_DEFAULT, i);
}
queue_for_each_hw_ctx(q, hctx, i) {
/*
* If no software queues are mapped to this hardware queue,
* disable it and free the request entries.
*/
if (!hctx->nr_ctx) {
/* Never unmap queue 0. We need it as a
* fallback in case of a new remap fails
* allocation
*/
if (i)
__blk_mq_free_map_and_rqs(set, i);
hctx->tags = NULL;
continue;
}
hctx->tags = set->tags[i];
WARN_ON(!hctx->tags);
/*
* Set the map size to the number of mapped software queues.
* This is more accurate and more efficient than looping
* over all possibly mapped software queues.
*/
sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
/*
* Initialize batch roundrobin counts
*/
hctx->next_cpu = blk_mq_first_mapped_cpu(hctx);
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
}
}
/*
* Caller needs to ensure that we're either frozen/quiesced, or that
* the queue isn't live yet.
*/
static void queue_set_hctx_shared(struct request_queue *q, bool shared)
{
struct blk_mq_hw_ctx *hctx;
int i;
queue_for_each_hw_ctx(q, hctx, i) {
if (shared) {
hctx->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
} else {
blk_mq_tag_idle(hctx);
hctx->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
}
}
}
static void blk_mq_update_tag_set_shared(struct blk_mq_tag_set *set,
bool shared)
{
struct request_queue *q;
lockdep_assert_held(&set->tag_list_lock);
list_for_each_entry(q, &set->tag_list, tag_set_list) {
blk_mq_freeze_queue(q);
queue_set_hctx_shared(q, shared);
blk_mq_unfreeze_queue(q);
}
}
static void blk_mq_del_queue_tag_set(struct request_queue *q)
{
struct blk_mq_tag_set *set = q->tag_set;
mutex_lock(&set->tag_list_lock);
list_del(&q->tag_set_list);
if (list_is_singular(&set->tag_list)) {
/* just transitioned to unshared */
set->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
/* update existing queue */
blk_mq_update_tag_set_shared(set, false);
}
mutex_unlock(&set->tag_list_lock);
INIT_LIST_HEAD(&q->tag_set_list);
}
static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
struct request_queue *q)
{
mutex_lock(&set->tag_list_lock);
/*
* Check to see if we're transitioning to shared (from 1 to 2 queues).
*/
if (!list_empty(&set->tag_list) &&
!(set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
set->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
/* update existing queue */
blk_mq_update_tag_set_shared(set, true);
}
if (set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
queue_set_hctx_shared(q, true);
list_add_tail(&q->tag_set_list, &set->tag_list);
mutex_unlock(&set->tag_list_lock);
}
/* All allocations will be freed in release handler of q->mq_kobj */
static int blk_mq_alloc_ctxs(struct request_queue *q)
{
struct blk_mq_ctxs *ctxs;
int cpu;
ctxs = kzalloc(sizeof(*ctxs), GFP_KERNEL);
if (!ctxs)
return -ENOMEM;
ctxs->queue_ctx = alloc_percpu(struct blk_mq_ctx);
if (!ctxs->queue_ctx)
goto fail;
for_each_possible_cpu(cpu) {
struct blk_mq_ctx *ctx = per_cpu_ptr(ctxs->queue_ctx, cpu);
ctx->ctxs = ctxs;
}
q->mq_kobj = &ctxs->kobj;
q->queue_ctx = ctxs->queue_ctx;
return 0;
fail:
kfree(ctxs);
return -ENOMEM;
}
/*
* It is the actual release handler for mq, but we do it from
* request queue's release handler for avoiding use-after-free
* and headache because q->mq_kobj shouldn't have been introduced,
* but we can't group ctx/kctx kobj without it.
*/
void blk_mq_release(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx, *next;
int i;
queue_for_each_hw_ctx(q, hctx, i)
WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list));
/* all hctx are in .unused_hctx_list now */
list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) {
list_del_init(&hctx->hctx_list);
kobject_put(&hctx->kobj);
}
kfree(q->queue_hw_ctx);
/*
* release .mq_kobj and sw queue's kobject now because
* both share lifetime with request queue.
*/
blk_mq_sysfs_deinit(q);
}
static struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set,
void *queuedata)
{
struct request_queue *q;
int ret;
q = blk_alloc_queue(set->numa_node, set->flags & BLK_MQ_F_BLOCKING);
if (!q)
return ERR_PTR(-ENOMEM);
q->queuedata = queuedata;
ret = blk_mq_init_allocated_queue(set, q);
if (ret) {
blk_cleanup_queue(q);
return ERR_PTR(ret);
}
return q;
}
struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
{
return blk_mq_init_queue_data(set, NULL);
}
EXPORT_SYMBOL(blk_mq_init_queue);
struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set, void *queuedata,
struct lock_class_key *lkclass)
{
struct request_queue *q;
struct gendisk *disk;
q = blk_mq_init_queue_data(set, queuedata);
if (IS_ERR(q))
return ERR_CAST(q);
disk = __alloc_disk_node(q, set->numa_node, lkclass);
if (!disk) {
blk_cleanup_queue(q);
return ERR_PTR(-ENOMEM);
}
return disk;
}
EXPORT_SYMBOL(__blk_mq_alloc_disk);
static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx(
struct blk_mq_tag_set *set, struct request_queue *q,
int hctx_idx, int node)
{
struct blk_mq_hw_ctx *hctx = NULL, *tmp;
/* reuse dead hctx first */
spin_lock(&q->unused_hctx_lock);
list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) {
if (tmp->numa_node == node) {
hctx = tmp;
break;
}
}
if (hctx)
list_del_init(&hctx->hctx_list);
spin_unlock(&q->unused_hctx_lock);
if (!hctx)
hctx = blk_mq_alloc_hctx(q, set, node);
if (!hctx)
goto fail;
if (blk_mq_init_hctx(q, set, hctx, hctx_idx))
goto free_hctx;
return hctx;
free_hctx:
kobject_put(&hctx->kobj);
fail:
return NULL;
}
static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
struct request_queue *q)
{
int i, j, end;
struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
if (q->nr_hw_queues < set->nr_hw_queues) {
struct blk_mq_hw_ctx **new_hctxs;
new_hctxs = kcalloc_node(set->nr_hw_queues,
sizeof(*new_hctxs), GFP_KERNEL,
set->numa_node);
if (!new_hctxs)
return;
if (hctxs)
memcpy(new_hctxs, hctxs, q->nr_hw_queues *
sizeof(*hctxs));
q->queue_hw_ctx = new_hctxs;
kfree(hctxs);
hctxs = new_hctxs;
}
/* protect against switching io scheduler */
mutex_lock(&q->sysfs_lock);
for (i = 0; i < set->nr_hw_queues; i++) {
int node;
struct blk_mq_hw_ctx *hctx;
node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], i);
/*
* If the hw queue has been mapped to another numa node,
* we need to realloc the hctx. If allocation fails, fallback
* to use the previous one.
*/
if (hctxs[i] && (hctxs[i]->numa_node == node))
continue;
hctx = blk_mq_alloc_and_init_hctx(set, q, i, node);
if (hctx) {
if (hctxs[i])
blk_mq_exit_hctx(q, set, hctxs[i], i);
hctxs[i] = hctx;
} else {
if (hctxs[i])
pr_warn("Allocate new hctx on node %d fails,\
fallback to previous one on node %d\n",
node, hctxs[i]->numa_node);
else
break;
}
}
/*
* Increasing nr_hw_queues fails. Free the newly allocated
* hctxs and keep the previous q->nr_hw_queues.
*/
if (i != set->nr_hw_queues) {
j = q->nr_hw_queues;
end = i;
} else {
j = i;
end = q->nr_hw_queues;
q->nr_hw_queues = set->nr_hw_queues;
}
for (; j < end; j++) {
struct blk_mq_hw_ctx *hctx = hctxs[j];
if (hctx) {
blk_mq_exit_hctx(q, set, hctx, j);
hctxs[j] = NULL;
}
}
mutex_unlock(&q->sysfs_lock);
}
int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
struct request_queue *q)
{
WARN_ON_ONCE(blk_queue_has_srcu(q) !=
!!(set->flags & BLK_MQ_F_BLOCKING));
/* mark the queue as mq asap */
q->mq_ops = set->ops;
q->poll_cb = blk_stat_alloc_callback(blk_mq_poll_stats_fn,
blk_mq_poll_stats_bkt,
BLK_MQ_POLL_STATS_BKTS, q);
if (!q->poll_cb)
goto err_exit;
if (blk_mq_alloc_ctxs(q))
goto err_poll;
/* init q->mq_kobj and sw queues' kobjects */
blk_mq_sysfs_init(q);
INIT_LIST_HEAD(&q->unused_hctx_list);
spin_lock_init(&q->unused_hctx_lock);
blk_mq_realloc_hw_ctxs(set, q);
if (!q->nr_hw_queues)
goto err_hctxs;
INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
q->tag_set = set;
q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
if (set->nr_maps > HCTX_TYPE_POLL &&
set->map[HCTX_TYPE_POLL].nr_queues)
blk_queue_flag_set(QUEUE_FLAG_POLL, q);
INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
INIT_LIST_HEAD(&q->requeue_list);
spin_lock_init(&q->requeue_lock);
q->nr_requests = set->queue_depth;
/*
* Default to classic polling
*/
q->poll_nsec = BLK_MQ_POLL_CLASSIC;
blk_mq_init_cpu_queues(q, set->nr_hw_queues);
blk_mq_add_queue_tag_set(set, q);
blk_mq_map_swqueue(q);
return 0;
err_hctxs:
kfree(q->queue_hw_ctx);
q->nr_hw_queues = 0;
blk_mq_sysfs_deinit(q);
err_poll:
blk_stat_free_callback(q->poll_cb);
q->poll_cb = NULL;
err_exit:
q->mq_ops = NULL;
return -ENOMEM;
}
EXPORT_SYMBOL(blk_mq_init_allocated_queue);
/* tags can _not_ be used after returning from blk_mq_exit_queue */
void blk_mq_exit_queue(struct request_queue *q)
{
struct blk_mq_tag_set *set = q->tag_set;
/* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */
blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
/* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */
blk_mq_del_queue_tag_set(q);
}
static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
{
int i;
if (blk_mq_is_shared_tags(set->flags)) {
set->shared_tags = blk_mq_alloc_map_and_rqs(set,
BLK_MQ_NO_HCTX_IDX,
set->queue_depth);
if (!set->shared_tags)
return -ENOMEM;
}
for (i = 0; i < set->nr_hw_queues; i++) {
if (!__blk_mq_alloc_map_and_rqs(set, i))
goto out_unwind;
cond_resched();
}
return 0;
out_unwind:
while (--i >= 0)
__blk_mq_free_map_and_rqs(set, i);
if (blk_mq_is_shared_tags(set->flags)) {
blk_mq_free_map_and_rqs(set, set->shared_tags,
BLK_MQ_NO_HCTX_IDX);
}
return -ENOMEM;
}
/*
* Allocate the request maps associated with this tag_set. Note that this
* may reduce the depth asked for, if memory is tight. set->queue_depth
* will be updated to reflect the allocated depth.
*/
static int blk_mq_alloc_set_map_and_rqs(struct blk_mq_tag_set *set)
{
unsigned int depth;
int err;
depth = set->queue_depth;
do {
err = __blk_mq_alloc_rq_maps(set);
if (!err)
break;
set->queue_depth >>= 1;
if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
err = -ENOMEM;
break;
}
} while (set->queue_depth);
if (!set->queue_depth || err) {
pr_err("blk-mq: failed to allocate request map\n");
return -ENOMEM;
}
if (depth != set->queue_depth)
pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
depth, set->queue_depth);
return 0;
}
static int blk_mq_update_queue_map(struct blk_mq_tag_set *set)
{
/*
* blk_mq_map_queues() and multiple .map_queues() implementations
* expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the
* number of hardware queues.
*/
if (set->nr_maps == 1)
set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues;
if (set->ops->map_queues && !is_kdump_kernel()) {
int i;
/*
* transport .map_queues is usually done in the following
* way:
*
* for (queue = 0; queue < set->nr_hw_queues; queue++) {
* mask = get_cpu_mask(queue)
* for_each_cpu(cpu, mask)
* set->map[x].mq_map[cpu] = queue;
* }
*
* When we need to remap, the table has to be cleared for
* killing stale mapping since one CPU may not be mapped
* to any hw queue.
*/
for (i = 0; i < set->nr_maps; i++)
blk_mq_clear_mq_map(&set->map[i]);
return set->ops->map_queues(set);
} else {
BUG_ON(set->nr_maps > 1);
return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
}
}
static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set,
int cur_nr_hw_queues, int new_nr_hw_queues)
{
struct blk_mq_tags **new_tags;
if (cur_nr_hw_queues >= new_nr_hw_queues)
return 0;
new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *),
GFP_KERNEL, set->numa_node);
if (!new_tags)
return -ENOMEM;
if (set->tags)
memcpy(new_tags, set->tags, cur_nr_hw_queues *
sizeof(*set->tags));
kfree(set->tags);
set->tags = new_tags;
set->nr_hw_queues = new_nr_hw_queues;
return 0;
}
static int blk_mq_alloc_tag_set_tags(struct blk_mq_tag_set *set,
int new_nr_hw_queues)
{
return blk_mq_realloc_tag_set_tags(set, 0, new_nr_hw_queues);
}
/*
* Alloc a tag set to be associated with one or more request queues.
* May fail with EINVAL for various error conditions. May adjust the
* requested depth down, if it's too large. In that case, the set
* value will be stored in set->queue_depth.
*/
int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
{
int i, ret;
BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
if (!set->nr_hw_queues)
return -EINVAL;
if (!set->queue_depth)
return -EINVAL;
if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
return -EINVAL;
if (!set->ops->queue_rq)
return -EINVAL;
if (!set->ops->get_budget ^ !set->ops->put_budget)
return -EINVAL;
if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
pr_info("blk-mq: reduced tag depth to %u\n",
BLK_MQ_MAX_DEPTH);
set->queue_depth = BLK_MQ_MAX_DEPTH;
}
if (!set->nr_maps)
set->nr_maps = 1;
else if (set->nr_maps > HCTX_MAX_TYPES)
return -EINVAL;
/*
* If a crashdump is active, then we are potentially in a very
* memory constrained environment. Limit us to 1 queue and
* 64 tags to prevent using too much memory.
*/
if (is_kdump_kernel()) {
set->nr_hw_queues = 1;
set->nr_maps = 1;
set->queue_depth = min(64U, set->queue_depth);
}
/*
* There is no use for more h/w queues than cpus if we just have
* a single map
*/
if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids)
set->nr_hw_queues = nr_cpu_ids;
if (blk_mq_alloc_tag_set_tags(set, set->nr_hw_queues) < 0)
return -ENOMEM;
ret = -ENOMEM;
for (i = 0; i < set->nr_maps; i++) {
set->map[i].mq_map = kcalloc_node(nr_cpu_ids,
sizeof(set->map[i].mq_map[0]),
GFP_KERNEL, set->numa_node);
if (!set->map[i].mq_map)
goto out_free_mq_map;
set->map[i].nr_queues = is_kdump_kernel() ? 1 : set->nr_hw_queues;
}
ret = blk_mq_update_queue_map(set);
if (ret)
goto out_free_mq_map;
ret = blk_mq_alloc_set_map_and_rqs(set);
if (ret)
goto out_free_mq_map;
mutex_init(&set->tag_list_lock);
INIT_LIST_HEAD(&set->tag_list);
return 0;
out_free_mq_map:
for (i = 0; i < set->nr_maps; i++) {
kfree(set->map[i].mq_map);
set->map[i].mq_map = NULL;
}
kfree(set->tags);
set->tags = NULL;
return ret;
}
EXPORT_SYMBOL(blk_mq_alloc_tag_set);
/* allocate and initialize a tagset for a simple single-queue device */
int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set *set,
const struct blk_mq_ops *ops, unsigned int queue_depth,
unsigned int set_flags)
{
memset(set, 0, sizeof(*set));
set->ops = ops;
set->nr_hw_queues = 1;
set->nr_maps = 1;
set->queue_depth = queue_depth;
set->numa_node = NUMA_NO_NODE;
set->flags = set_flags;
return blk_mq_alloc_tag_set(set);
}
EXPORT_SYMBOL_GPL(blk_mq_alloc_sq_tag_set);
void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
{
int i, j;
for (i = 0; i < set->nr_hw_queues; i++)
__blk_mq_free_map_and_rqs(set, i);
if (blk_mq_is_shared_tags(set->flags)) {
blk_mq_free_map_and_rqs(set, set->shared_tags,
BLK_MQ_NO_HCTX_IDX);
}
for (j = 0; j < set->nr_maps; j++) {
kfree(set->map[j].mq_map);
set->map[j].mq_map = NULL;
}
kfree(set->tags);
set->tags = NULL;
}
EXPORT_SYMBOL(blk_mq_free_tag_set);
int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
{
struct blk_mq_tag_set *set = q->tag_set;
struct blk_mq_hw_ctx *hctx;
int i, ret;
if (!set)
return -EINVAL;
if (q->nr_requests == nr)
return 0;
blk_mq_freeze_queue(q);
blk_mq_quiesce_queue(q);
ret = 0;
queue_for_each_hw_ctx(q, hctx, i) {
if (!hctx->tags)
continue;
/*
* If we're using an MQ scheduler, just update the scheduler
* queue depth. This is similar to what the old code would do.
*/
if (hctx->sched_tags) {
ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
nr, true);
} else {
ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
false);
}
if (ret)
break;
if (q->elevator && q->elevator->type->ops.depth_updated)
q->elevator->type->ops.depth_updated(hctx);
}
if (!ret) {
q->nr_requests = nr;
if (blk_mq_is_shared_tags(set->flags)) {
if (q->elevator)
blk_mq_tag_update_sched_shared_tags(q);
else
blk_mq_tag_resize_shared_tags(set, nr);
}
}
blk_mq_unquiesce_queue(q);
blk_mq_unfreeze_queue(q);
return ret;
}
/*
* request_queue and elevator_type pair.
* It is just used by __blk_mq_update_nr_hw_queues to cache
* the elevator_type associated with a request_queue.
*/
struct blk_mq_qe_pair {
struct list_head node;
struct request_queue *q;
struct elevator_type *type;
};
/*
* Cache the elevator_type in qe pair list and switch the
* io scheduler to 'none'
*/
static bool blk_mq_elv_switch_none(struct list_head *head,
struct request_queue *q)
{
struct blk_mq_qe_pair *qe;
if (!q->elevator)
return true;
qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY);
if (!qe)
return false;
INIT_LIST_HEAD(&qe->node);
qe->q = q;
qe->type = q->elevator->type;
list_add(&qe->node, head);
mutex_lock(&q->sysfs_lock);
/*
* After elevator_switch_mq, the previous elevator_queue will be
* released by elevator_release. The reference of the io scheduler
* module get by elevator_get will also be put. So we need to get
* a reference of the io scheduler module here to prevent it to be
* removed.
*/
__module_get(qe->type->elevator_owner);
elevator_switch_mq(q, NULL);
mutex_unlock(&q->sysfs_lock);
return true;
}
static void blk_mq_elv_switch_back(struct list_head *head,
struct request_queue *q)
{
struct blk_mq_qe_pair *qe;
struct elevator_type *t = NULL;
list_for_each_entry(qe, head, node)
if (qe->q == q) {
t = qe->type;
break;
}
if (!t)
return;
list_del(&qe->node);
kfree(qe);
mutex_lock(&q->sysfs_lock);
elevator_switch_mq(q, t);
mutex_unlock(&q->sysfs_lock);
}
static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
int nr_hw_queues)
{
struct request_queue *q;
LIST_HEAD(head);
int prev_nr_hw_queues;
lockdep_assert_held(&set->tag_list_lock);
if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids)
nr_hw_queues = nr_cpu_ids;
if (nr_hw_queues < 1)
return;
if (set->nr_maps == 1 && nr_hw_queues == set->nr_hw_queues)
return;
list_for_each_entry(q, &set->tag_list, tag_set_list)
blk_mq_freeze_queue(q);
/*
* Switch IO scheduler to 'none', cleaning up the data associated
* with the previous scheduler. We will switch back once we are done
* updating the new sw to hw queue mappings.
*/
list_for_each_entry(q, &set->tag_list, tag_set_list)
if (!blk_mq_elv_switch_none(&head, q))
goto switch_back;
list_for_each_entry(q, &set->tag_list, tag_set_list) {
blk_mq_debugfs_unregister_hctxs(q);
blk_mq_sysfs_unregister(q);
}
prev_nr_hw_queues = set->nr_hw_queues;
if (blk_mq_realloc_tag_set_tags(set, set->nr_hw_queues, nr_hw_queues) <
0)
goto reregister;
set->nr_hw_queues = nr_hw_queues;
fallback:
blk_mq_update_queue_map(set);
list_for_each_entry(q, &set->tag_list, tag_set_list) {
blk_mq_realloc_hw_ctxs(set, q);
if (q->nr_hw_queues != set->nr_hw_queues) {
int i = prev_nr_hw_queues;
pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
nr_hw_queues, prev_nr_hw_queues);
for (; i < set->nr_hw_queues; i++)
__blk_mq_free_map_and_rqs(set, i);
set->nr_hw_queues = prev_nr_hw_queues;
blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
goto fallback;
}
blk_mq_map_swqueue(q);
}
reregister:
list_for_each_entry(q, &set->tag_list, tag_set_list) {
blk_mq_sysfs_register(q);
blk_mq_debugfs_register_hctxs(q);
}
switch_back:
list_for_each_entry(q, &set->tag_list, tag_set_list)
blk_mq_elv_switch_back(&head, q);
list_for_each_entry(q, &set->tag_list, tag_set_list)
blk_mq_unfreeze_queue(q);
}
void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
{
mutex_lock(&set->tag_list_lock);
__blk_mq_update_nr_hw_queues(set, nr_hw_queues);
mutex_unlock(&set->tag_list_lock);
}
EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
/* Enable polling stats and return whether they were already enabled. */
static bool blk_poll_stats_enable(struct request_queue *q)
{
if (q->poll_stat)
return true;
return blk_stats_alloc_enable(q);
}
static void blk_mq_poll_stats_start(struct request_queue *q)
{
/*
* We don't arm the callback if polling stats are not enabled or the
* callback is already active.
*/
if (!q->poll_stat || blk_stat_is_active(q->poll_cb))
return;
blk_stat_activate_msecs(q->poll_cb, 100);
}
static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb)
{
struct request_queue *q = cb->data;
int bucket;
for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS; bucket++) {
if (cb->stat[bucket].nr_samples)
q->poll_stat[bucket] = cb->stat[bucket];
}
}
static unsigned long blk_mq_poll_nsecs(struct request_queue *q,
struct request *rq)
{
unsigned long ret = 0;
int bucket;
/*
* If stats collection isn't on, don't sleep but turn it on for
* future users
*/
if (!blk_poll_stats_enable(q))
return 0;
/*
* As an optimistic guess, use half of the mean service time
* for this type of request. We can (and should) make this smarter.
* For instance, if the completion latencies are tight, we can
* get closer than just half the mean. This is especially
* important on devices where the completion latencies are longer
* than ~10 usec. We do use the stats for the relevant IO size
* if available which does lead to better estimates.
*/
bucket = blk_mq_poll_stats_bkt(rq);
if (bucket < 0)
return ret;
if (q->poll_stat[bucket].nr_samples)
ret = (q->poll_stat[bucket].mean + 1) / 2;
return ret;
}
static bool blk_mq_poll_hybrid(struct request_queue *q, blk_qc_t qc)
{
struct blk_mq_hw_ctx *hctx = blk_qc_to_hctx(q, qc);
struct request *rq = blk_qc_to_rq(hctx, qc);
struct hrtimer_sleeper hs;
enum hrtimer_mode mode;
unsigned int nsecs;
ktime_t kt;
/*
* If a request has completed on queue that uses an I/O scheduler, we
* won't get back a request from blk_qc_to_rq.
*/
if (!rq || (rq->rq_flags & RQF_MQ_POLL_SLEPT))
return false;
/*
* If we get here, hybrid polling is enabled. Hence poll_nsec can be:
*
* 0: use half of prev avg
* >0: use this specific value
*/
if (q->poll_nsec > 0)
nsecs = q->poll_nsec;
else
nsecs = blk_mq_poll_nsecs(q, rq);
if (!nsecs)
return false;
rq->rq_flags |= RQF_MQ_POLL_SLEPT;
/*
* This will be replaced with the stats tracking code, using
* 'avg_completion_time / 2' as the pre-sleep target.
*/
kt = nsecs;
mode = HRTIMER_MODE_REL;
hrtimer_init_sleeper_on_stack(&hs, CLOCK_MONOTONIC, mode);
hrtimer_set_expires(&hs.timer, kt);
do {
if (blk_mq_rq_state(rq) == MQ_RQ_COMPLETE)
break;
set_current_state(TASK_UNINTERRUPTIBLE);
hrtimer_sleeper_start_expires(&hs, mode);
if (hs.task)
io_schedule();
hrtimer_cancel(&hs.timer);
mode = HRTIMER_MODE_ABS;
} while (hs.task && !signal_pending(current));
__set_current_state(TASK_RUNNING);
destroy_hrtimer_on_stack(&hs.timer);
/*
* If we sleep, have the caller restart the poll loop to reset the
* state. Like for the other success return cases, the caller is
* responsible for checking if the IO completed. If the IO isn't
* complete, we'll get called again and will go straight to the busy
* poll loop.
*/
return true;
}
static int blk_mq_poll_classic(struct request_queue *q, blk_qc_t cookie,
struct io_comp_batch *iob, unsigned int flags)
{
struct blk_mq_hw_ctx *hctx = blk_qc_to_hctx(q, cookie);
long state = get_current_state();
int ret;
do {
ret = q->mq_ops->poll(hctx, iob);
if (ret > 0) {
__set_current_state(TASK_RUNNING);
return ret;
}
if (signal_pending_state(state, current))
__set_current_state(TASK_RUNNING);
if (task_is_running(current))
return 1;
if (ret < 0 || (flags & BLK_POLL_ONESHOT))
break;
cpu_relax();
} while (!need_resched());
__set_current_state(TASK_RUNNING);
return 0;
}
int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, struct io_comp_batch *iob,
unsigned int flags)
{
if (!(flags & BLK_POLL_NOSLEEP) &&
q->poll_nsec != BLK_MQ_POLL_CLASSIC) {
if (blk_mq_poll_hybrid(q, cookie))
return 1;
}
return blk_mq_poll_classic(q, cookie, iob, flags);
}
unsigned int blk_mq_rq_cpu(struct request *rq)
{
return rq->mq_ctx->cpu;
}
EXPORT_SYMBOL(blk_mq_rq_cpu);
void blk_mq_cancel_work_sync(struct request_queue *q)
{
if (queue_is_mq(q)) {
struct blk_mq_hw_ctx *hctx;
int i;
cancel_delayed_work_sync(&q->requeue_work);
queue_for_each_hw_ctx(q, hctx, i)
cancel_delayed_work_sync(&hctx->run_work);
}
}
static int __init blk_mq_init(void)
{
int i;
for_each_possible_cpu(i)
init_llist_head(&per_cpu(blk_cpu_done, i));
open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
"block/softirq:dead", NULL,
blk_softirq_cpu_dead);
cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
blk_mq_hctx_notify_dead);
cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE, "block/mq:online",
blk_mq_hctx_notify_online,
blk_mq_hctx_notify_offline);
return 0;
}
subsys_initcall(blk_mq_init);
Reference in a new issue View git blame Copy permalink