linux-stable/drivers/md/dm-rq.c
Linus Torvalds 6cdc577a18 - Update bio-based DM core to always call blk_queue_split() and update
DM targets to properly advertise discard limits that blk_queue_split()
   looks at when dtermining to split discard.  Whereby allowing DM core's
   own 'split_discard_bios' to be removed.
 
 - Improve DM cache target to provide support for discard passdown to the
   origin device.
 
 - Introduce support to directly boot to a DM mapped device from init by
   using dm-mod.create= module param.  This eliminates the need for an
   elaborate initramfs that is otherwise needed to create DM devices.
   This feature's implementation has been worked on for quite some time
   (got up to v12) and is of particular interest to Android and other
   more embedded platforms (e.g. ARM).
 
 - Rate limit errors from the DM integrity target that were identified as
   the cause for recent NMI hangs due to console limitations.
 
 - Add sanity checks for user input to thin-pool and external snapshot
   creation.
 
 - Remove some unused leftover kmem caches from when old .request_fn
   request-based support was removed.
 
 - Various small cleanups and fixes to targets (e.g. typos, needless
   unlikely() annotations, use struct_size(), remove needless
   .direct_access method from dm-snapshot)
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Merge tag 'for-5.1/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Update bio-based DM core to always call blk_queue_split() and update
   DM targets to properly advertise discard limits that
   blk_queue_split() looks at when dtermining to split discard. Whereby
   allowing DM core's own 'split_discard_bios' to be removed.

 - Improve DM cache target to provide support for discard passdown to
   the origin device.

 - Introduce support to directly boot to a DM mapped device from init by
   using dm-mod.create= module param. This eliminates the need for an
   elaborate initramfs that is otherwise needed to create DM devices.

   This feature's implementation has been worked on for quite some time
   (got up to v12) and is of particular interest to Android and other
   more embedded platforms (e.g. ARM).

 - Rate limit errors from the DM integrity target that were identified
   as the cause for recent NMI hangs due to console limitations.

 - Add sanity checks for user input to thin-pool and external snapshot
   creation.

 - Remove some unused leftover kmem caches from when old .request_fn
   request-based support was removed.

 - Various small cleanups and fixes to targets (e.g. typos, needless
   unlikely() annotations, use struct_size(), remove needless
   .direct_access method from dm-snapshot)

* tag 'for-5.1/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm integrity: limit the rate of error messages
  dm snapshot: don't define direct_access if we don't support it
  dm cache: add support for discard passdown to the origin device
  dm writecache: fix typo in name for writeback_wq
  dm: add support to directly boot to a mapped device
  dm thin: add sanity checks to thin-pool and external snapshot creation
  dm block manager: remove redundant unlikely annotation
  dm verity fec: remove redundant unlikely annotation
  dm integrity: remove redundant unlikely annotation
  dm: always call blk_queue_split() in dm_process_bio()
  dm: fix to_sector() for 32bit
  dm switch: use struct_size() in kzalloc()
  dm: remove unused _rq_tio_cache and _rq_cache
  dm: eliminate 'split_discard_bios' flag from DM target interface
  dm: update dm_process_bio() to split bio if in ->make_request_fn()
2019-03-09 17:40:27 -08:00

598 lines
15 KiB
C

/*
* Copyright (C) 2016 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
#include "dm-core.h"
#include "dm-rq.h"
#include <linux/elevator.h> /* for rq_end_sector() */
#include <linux/blk-mq.h>
#define DM_MSG_PREFIX "core-rq"
/*
* One of these is allocated per request.
*/
struct dm_rq_target_io {
struct mapped_device *md;
struct dm_target *ti;
struct request *orig, *clone;
struct kthread_work work;
blk_status_t error;
union map_info info;
struct dm_stats_aux stats_aux;
unsigned long duration_jiffies;
unsigned n_sectors;
unsigned completed;
};
#define DM_MQ_NR_HW_QUEUES 1
#define DM_MQ_QUEUE_DEPTH 2048
static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES;
static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH;
/*
* Request-based DM's mempools' reserved IOs set by the user.
*/
#define RESERVED_REQUEST_BASED_IOS 256
static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
unsigned dm_get_reserved_rq_based_ios(void)
{
return __dm_get_module_param(&reserved_rq_based_ios,
RESERVED_REQUEST_BASED_IOS, DM_RESERVED_MAX_IOS);
}
EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
static unsigned dm_get_blk_mq_nr_hw_queues(void)
{
return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32);
}
static unsigned dm_get_blk_mq_queue_depth(void)
{
return __dm_get_module_param(&dm_mq_queue_depth,
DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH);
}
int dm_request_based(struct mapped_device *md)
{
return queue_is_mq(md->queue);
}
void dm_start_queue(struct request_queue *q)
{
blk_mq_unquiesce_queue(q);
blk_mq_kick_requeue_list(q);
}
void dm_stop_queue(struct request_queue *q)
{
if (blk_mq_queue_stopped(q))
return;
blk_mq_quiesce_queue(q);
}
/*
* Partial completion handling for request-based dm
*/
static void end_clone_bio(struct bio *clone)
{
struct dm_rq_clone_bio_info *info =
container_of(clone, struct dm_rq_clone_bio_info, clone);
struct dm_rq_target_io *tio = info->tio;
unsigned int nr_bytes = info->orig->bi_iter.bi_size;
blk_status_t error = clone->bi_status;
bool is_last = !clone->bi_next;
bio_put(clone);
if (tio->error)
/*
* An error has already been detected on the request.
* Once error occurred, just let clone->end_io() handle
* the remainder.
*/
return;
else if (error) {
/*
* Don't notice the error to the upper layer yet.
* The error handling decision is made by the target driver,
* when the request is completed.
*/
tio->error = error;
goto exit;
}
/*
* I/O for the bio successfully completed.
* Notice the data completion to the upper layer.
*/
tio->completed += nr_bytes;
/*
* Update the original request.
* Do not use blk_end_request() here, because it may complete
* the original request before the clone, and break the ordering.
*/
if (is_last)
exit:
blk_update_request(tio->orig, BLK_STS_OK, tio->completed);
}
static struct dm_rq_target_io *tio_from_request(struct request *rq)
{
return blk_mq_rq_to_pdu(rq);
}
static void rq_end_stats(struct mapped_device *md, struct request *orig)
{
if (unlikely(dm_stats_used(&md->stats))) {
struct dm_rq_target_io *tio = tio_from_request(orig);
tio->duration_jiffies = jiffies - tio->duration_jiffies;
dm_stats_account_io(&md->stats, rq_data_dir(orig),
blk_rq_pos(orig), tio->n_sectors, true,
tio->duration_jiffies, &tio->stats_aux);
}
}
/*
* Don't touch any member of the md after calling this function because
* the md may be freed in dm_put() at the end of this function.
* Or do dm_get() before calling this function and dm_put() later.
*/
static void rq_completed(struct mapped_device *md)
{
/* nudge anyone waiting on suspend queue */
if (unlikely(wq_has_sleeper(&md->wait)))
wake_up(&md->wait);
/*
* dm_put() must be at the end of this function. See the comment above
*/
dm_put(md);
}
/*
* Complete the clone and the original request.
* Must be called without clone's queue lock held,
* see end_clone_request() for more details.
*/
static void dm_end_request(struct request *clone, blk_status_t error)
{
struct dm_rq_target_io *tio = clone->end_io_data;
struct mapped_device *md = tio->md;
struct request *rq = tio->orig;
blk_rq_unprep_clone(clone);
tio->ti->type->release_clone_rq(clone);
rq_end_stats(md, rq);
blk_mq_end_request(rq, error);
rq_completed(md);
}
static void __dm_mq_kick_requeue_list(struct request_queue *q, unsigned long msecs)
{
blk_mq_delay_kick_requeue_list(q, msecs);
}
void dm_mq_kick_requeue_list(struct mapped_device *md)
{
__dm_mq_kick_requeue_list(dm_get_md_queue(md), 0);
}
EXPORT_SYMBOL(dm_mq_kick_requeue_list);
static void dm_mq_delay_requeue_request(struct request *rq, unsigned long msecs)
{
blk_mq_requeue_request(rq, false);
__dm_mq_kick_requeue_list(rq->q, msecs);
}
static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_requeue)
{
struct mapped_device *md = tio->md;
struct request *rq = tio->orig;
unsigned long delay_ms = delay_requeue ? 100 : 0;
rq_end_stats(md, rq);
if (tio->clone) {
blk_rq_unprep_clone(tio->clone);
tio->ti->type->release_clone_rq(tio->clone);
}
dm_mq_delay_requeue_request(rq, delay_ms);
rq_completed(md);
}
static void dm_done(struct request *clone, blk_status_t error, bool mapped)
{
int r = DM_ENDIO_DONE;
struct dm_rq_target_io *tio = clone->end_io_data;
dm_request_endio_fn rq_end_io = NULL;
if (tio->ti) {
rq_end_io = tio->ti->type->rq_end_io;
if (mapped && rq_end_io)
r = rq_end_io(tio->ti, clone, error, &tio->info);
}
if (unlikely(error == BLK_STS_TARGET)) {
if (req_op(clone) == REQ_OP_WRITE_SAME &&
!clone->q->limits.max_write_same_sectors)
disable_write_same(tio->md);
if (req_op(clone) == REQ_OP_WRITE_ZEROES &&
!clone->q->limits.max_write_zeroes_sectors)
disable_write_zeroes(tio->md);
}
switch (r) {
case DM_ENDIO_DONE:
/* The target wants to complete the I/O */
dm_end_request(clone, error);
break;
case DM_ENDIO_INCOMPLETE:
/* The target will handle the I/O */
return;
case DM_ENDIO_REQUEUE:
/* The target wants to requeue the I/O */
dm_requeue_original_request(tio, false);
break;
case DM_ENDIO_DELAY_REQUEUE:
/* The target wants to requeue the I/O after a delay */
dm_requeue_original_request(tio, true);
break;
default:
DMWARN("unimplemented target endio return value: %d", r);
BUG();
}
}
/*
* Request completion handler for request-based dm
*/
static void dm_softirq_done(struct request *rq)
{
bool mapped = true;
struct dm_rq_target_io *tio = tio_from_request(rq);
struct request *clone = tio->clone;
if (!clone) {
struct mapped_device *md = tio->md;
rq_end_stats(md, rq);
blk_mq_end_request(rq, tio->error);
rq_completed(md);
return;
}
if (rq->rq_flags & RQF_FAILED)
mapped = false;
dm_done(clone, tio->error, mapped);
}
/*
* Complete the clone and the original request with the error status
* through softirq context.
*/
static void dm_complete_request(struct request *rq, blk_status_t error)
{
struct dm_rq_target_io *tio = tio_from_request(rq);
tio->error = error;
blk_mq_complete_request(rq);
}
/*
* Complete the not-mapped clone and the original request with the error status
* through softirq context.
* Target's rq_end_io() function isn't called.
* This may be used when the target's clone_and_map_rq() function fails.
*/
static void dm_kill_unmapped_request(struct request *rq, blk_status_t error)
{
rq->rq_flags |= RQF_FAILED;
dm_complete_request(rq, error);
}
static void end_clone_request(struct request *clone, blk_status_t error)
{
struct dm_rq_target_io *tio = clone->end_io_data;
dm_complete_request(tio->orig, error);
}
static blk_status_t dm_dispatch_clone_request(struct request *clone, struct request *rq)
{
blk_status_t r;
if (blk_queue_io_stat(clone->q))
clone->rq_flags |= RQF_IO_STAT;
clone->start_time_ns = ktime_get_ns();
r = blk_insert_cloned_request(clone->q, clone);
if (r != BLK_STS_OK && r != BLK_STS_RESOURCE && r != BLK_STS_DEV_RESOURCE)
/* must complete clone in terms of original request */
dm_complete_request(rq, r);
return r;
}
static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
void *data)
{
struct dm_rq_target_io *tio = data;
struct dm_rq_clone_bio_info *info =
container_of(bio, struct dm_rq_clone_bio_info, clone);
info->orig = bio_orig;
info->tio = tio;
bio->bi_end_io = end_clone_bio;
return 0;
}
static int setup_clone(struct request *clone, struct request *rq,
struct dm_rq_target_io *tio, gfp_t gfp_mask)
{
int r;
r = blk_rq_prep_clone(clone, rq, &tio->md->bs, gfp_mask,
dm_rq_bio_constructor, tio);
if (r)
return r;
clone->end_io = end_clone_request;
clone->end_io_data = tio;
tio->clone = clone;
return 0;
}
static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
struct mapped_device *md)
{
tio->md = md;
tio->ti = NULL;
tio->clone = NULL;
tio->orig = rq;
tio->error = 0;
tio->completed = 0;
/*
* Avoid initializing info for blk-mq; it passes
* target-specific data through info.ptr
* (see: dm_mq_init_request)
*/
if (!md->init_tio_pdu)
memset(&tio->info, 0, sizeof(tio->info));
}
/*
* Returns:
* DM_MAPIO_* : the request has been processed as indicated
* DM_MAPIO_REQUEUE : the original request needs to be immediately requeued
* < 0 : the request was completed due to failure
*/
static int map_request(struct dm_rq_target_io *tio)
{
int r;
struct dm_target *ti = tio->ti;
struct mapped_device *md = tio->md;
struct request *rq = tio->orig;
struct request *clone = NULL;
blk_status_t ret;
r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone);
switch (r) {
case DM_MAPIO_SUBMITTED:
/* The target has taken the I/O to submit by itself later */
break;
case DM_MAPIO_REMAPPED:
if (setup_clone(clone, rq, tio, GFP_ATOMIC)) {
/* -ENOMEM */
ti->type->release_clone_rq(clone);
return DM_MAPIO_REQUEUE;
}
/* The target has remapped the I/O so dispatch it */
trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
blk_rq_pos(rq));
ret = dm_dispatch_clone_request(clone, rq);
if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) {
blk_rq_unprep_clone(clone);
tio->ti->type->release_clone_rq(clone);
tio->clone = NULL;
return DM_MAPIO_REQUEUE;
}
break;
case DM_MAPIO_REQUEUE:
/* The target wants to requeue the I/O */
break;
case DM_MAPIO_DELAY_REQUEUE:
/* The target wants to requeue the I/O after a delay */
dm_requeue_original_request(tio, true);
break;
case DM_MAPIO_KILL:
/* The target wants to complete the I/O */
dm_kill_unmapped_request(rq, BLK_STS_IOERR);
break;
default:
DMWARN("unimplemented target map return value: %d", r);
BUG();
}
return r;
}
/* DEPRECATED: previously used for request-based merge heuristic in dm_request_fn() */
ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf)
{
return sprintf(buf, "%u\n", 0);
}
ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
const char *buf, size_t count)
{
return count;
}
static void dm_start_request(struct mapped_device *md, struct request *orig)
{
blk_mq_start_request(orig);
if (unlikely(dm_stats_used(&md->stats))) {
struct dm_rq_target_io *tio = tio_from_request(orig);
tio->duration_jiffies = jiffies;
tio->n_sectors = blk_rq_sectors(orig);
dm_stats_account_io(&md->stats, rq_data_dir(orig),
blk_rq_pos(orig), tio->n_sectors, false, 0,
&tio->stats_aux);
}
/*
* Hold the md reference here for the in-flight I/O.
* We can't rely on the reference count by device opener,
* because the device may be closed during the request completion
* when all bios are completed.
* See the comment in rq_completed() too.
*/
dm_get(md);
}
static int dm_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
unsigned int hctx_idx, unsigned int numa_node)
{
struct mapped_device *md = set->driver_data;
struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
/*
* Must initialize md member of tio, otherwise it won't
* be available in dm_mq_queue_rq.
*/
tio->md = md;
if (md->init_tio_pdu) {
/* target-specific per-io data is immediately after the tio */
tio->info.ptr = tio + 1;
}
return 0;
}
static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
struct request *rq = bd->rq;
struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
struct mapped_device *md = tio->md;
struct dm_target *ti = md->immutable_target;
if (unlikely(!ti)) {
int srcu_idx;
struct dm_table *map = dm_get_live_table(md, &srcu_idx);
ti = dm_table_find_target(map, 0);
dm_put_live_table(md, srcu_idx);
}
if (ti->type->busy && ti->type->busy(ti))
return BLK_STS_RESOURCE;
dm_start_request(md, rq);
/* Init tio using md established in .init_request */
init_tio(tio, rq, md);
/*
* Establish tio->ti before calling map_request().
*/
tio->ti = ti;
/* Direct call is fine since .queue_rq allows allocations */
if (map_request(tio) == DM_MAPIO_REQUEUE) {
/* Undo dm_start_request() before requeuing */
rq_end_stats(md, rq);
rq_completed(md);
return BLK_STS_RESOURCE;
}
return BLK_STS_OK;
}
static const struct blk_mq_ops dm_mq_ops = {
.queue_rq = dm_mq_queue_rq,
.complete = dm_softirq_done,
.init_request = dm_mq_init_request,
};
int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
{
struct request_queue *q;
struct dm_target *immutable_tgt;
int err;
md->tag_set = kzalloc_node(sizeof(struct blk_mq_tag_set), GFP_KERNEL, md->numa_node_id);
if (!md->tag_set)
return -ENOMEM;
md->tag_set->ops = &dm_mq_ops;
md->tag_set->queue_depth = dm_get_blk_mq_queue_depth();
md->tag_set->numa_node = md->numa_node_id;
md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues();
md->tag_set->driver_data = md;
md->tag_set->cmd_size = sizeof(struct dm_rq_target_io);
immutable_tgt = dm_table_get_immutable_target(t);
if (immutable_tgt && immutable_tgt->per_io_data_size) {
/* any target-specific per-io data is immediately after the tio */
md->tag_set->cmd_size += immutable_tgt->per_io_data_size;
md->init_tio_pdu = true;
}
err = blk_mq_alloc_tag_set(md->tag_set);
if (err)
goto out_kfree_tag_set;
q = blk_mq_init_allocated_queue(md->tag_set, md->queue);
if (IS_ERR(q)) {
err = PTR_ERR(q);
goto out_tag_set;
}
return 0;
out_tag_set:
blk_mq_free_tag_set(md->tag_set);
out_kfree_tag_set:
kfree(md->tag_set);
return err;
}
void dm_mq_cleanup_mapped_device(struct mapped_device *md)
{
if (md->tag_set) {
blk_mq_free_tag_set(md->tag_set);
kfree(md->tag_set);
}
}
module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
/* Unused, but preserved for userspace compatibility */
static bool use_blk_mq = true;
module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices");
module_param(dm_mq_nr_hw_queues, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(dm_mq_nr_hw_queues, "Number of hardware queues for request-based dm-mq devices");
module_param(dm_mq_queue_depth, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(dm_mq_queue_depth, "Queue depth for request-based dm-mq devices");