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![Mike Snitzer](/assets/img/avatar_default.png)
bio_start_io_acct_time() interface is like bio_start_io_acct() that allows start_time to be passed in. This gives drivers the ability to defer starting accounting until after IO is issued (but possibily not entirely due to bio splitting). Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Link: https://lore.kernel.org/r/20220128155841.39644-2-snitzer@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
1351 lines
36 KiB
C
1351 lines
36 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 1994, Karl Keyte: Added support for disk statistics
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* Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
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* Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de>
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* kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au>
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* - July2000
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* bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001
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*/
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/*
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* This handles all read/write requests to block devices
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/blk-pm.h>
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#include <linux/blk-integrity.h>
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#include <linux/highmem.h>
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#include <linux/mm.h>
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#include <linux/pagemap.h>
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#include <linux/kernel_stat.h>
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#include <linux/string.h>
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#include <linux/init.h>
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#include <linux/completion.h>
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#include <linux/slab.h>
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#include <linux/swap.h>
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#include <linux/writeback.h>
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#include <linux/task_io_accounting_ops.h>
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#include <linux/fault-inject.h>
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#include <linux/list_sort.h>
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#include <linux/delay.h>
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#include <linux/ratelimit.h>
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#include <linux/pm_runtime.h>
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#include <linux/blk-cgroup.h>
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#include <linux/t10-pi.h>
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#include <linux/debugfs.h>
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#include <linux/bpf.h>
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#include <linux/psi.h>
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#include <linux/part_stat.h>
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#include <linux/sched/sysctl.h>
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#include <linux/blk-crypto.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/block.h>
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#include "blk.h"
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#include "blk-mq-sched.h"
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#include "blk-pm.h"
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#include "blk-throttle.h"
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struct dentry *blk_debugfs_root;
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_split);
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert);
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DEFINE_IDA(blk_queue_ida);
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/*
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* For queue allocation
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*/
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struct kmem_cache *blk_requestq_cachep;
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struct kmem_cache *blk_requestq_srcu_cachep;
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/*
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* Controlling structure to kblockd
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*/
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static struct workqueue_struct *kblockd_workqueue;
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/**
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* blk_queue_flag_set - atomically set a queue flag
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* @flag: flag to be set
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* @q: request queue
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*/
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void blk_queue_flag_set(unsigned int flag, struct request_queue *q)
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{
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set_bit(flag, &q->queue_flags);
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}
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EXPORT_SYMBOL(blk_queue_flag_set);
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/**
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* blk_queue_flag_clear - atomically clear a queue flag
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* @flag: flag to be cleared
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* @q: request queue
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*/
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void blk_queue_flag_clear(unsigned int flag, struct request_queue *q)
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{
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clear_bit(flag, &q->queue_flags);
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}
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EXPORT_SYMBOL(blk_queue_flag_clear);
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/**
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* blk_queue_flag_test_and_set - atomically test and set a queue flag
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* @flag: flag to be set
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* @q: request queue
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*
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* Returns the previous value of @flag - 0 if the flag was not set and 1 if
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* the flag was already set.
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*/
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bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q)
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{
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return test_and_set_bit(flag, &q->queue_flags);
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}
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EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set);
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#define REQ_OP_NAME(name) [REQ_OP_##name] = #name
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static const char *const blk_op_name[] = {
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REQ_OP_NAME(READ),
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REQ_OP_NAME(WRITE),
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REQ_OP_NAME(FLUSH),
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REQ_OP_NAME(DISCARD),
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REQ_OP_NAME(SECURE_ERASE),
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REQ_OP_NAME(ZONE_RESET),
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REQ_OP_NAME(ZONE_RESET_ALL),
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REQ_OP_NAME(ZONE_OPEN),
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REQ_OP_NAME(ZONE_CLOSE),
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REQ_OP_NAME(ZONE_FINISH),
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REQ_OP_NAME(ZONE_APPEND),
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REQ_OP_NAME(WRITE_SAME),
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REQ_OP_NAME(WRITE_ZEROES),
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REQ_OP_NAME(DRV_IN),
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REQ_OP_NAME(DRV_OUT),
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};
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#undef REQ_OP_NAME
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/**
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* blk_op_str - Return string XXX in the REQ_OP_XXX.
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* @op: REQ_OP_XXX.
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*
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* Description: Centralize block layer function to convert REQ_OP_XXX into
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* string format. Useful in the debugging and tracing bio or request. For
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* invalid REQ_OP_XXX it returns string "UNKNOWN".
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*/
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inline const char *blk_op_str(unsigned int op)
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{
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const char *op_str = "UNKNOWN";
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if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op])
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op_str = blk_op_name[op];
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return op_str;
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}
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EXPORT_SYMBOL_GPL(blk_op_str);
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static const struct {
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int errno;
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const char *name;
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} blk_errors[] = {
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[BLK_STS_OK] = { 0, "" },
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[BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" },
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[BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" },
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[BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" },
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[BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" },
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[BLK_STS_TARGET] = { -EREMOTEIO, "critical target" },
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[BLK_STS_NEXUS] = { -EBADE, "critical nexus" },
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[BLK_STS_MEDIUM] = { -ENODATA, "critical medium" },
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[BLK_STS_PROTECTION] = { -EILSEQ, "protection" },
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[BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" },
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[BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" },
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[BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" },
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/* device mapper special case, should not leak out: */
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[BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" },
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/* zone device specific errors */
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[BLK_STS_ZONE_OPEN_RESOURCE] = { -ETOOMANYREFS, "open zones exceeded" },
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[BLK_STS_ZONE_ACTIVE_RESOURCE] = { -EOVERFLOW, "active zones exceeded" },
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/* everything else not covered above: */
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[BLK_STS_IOERR] = { -EIO, "I/O" },
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};
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blk_status_t errno_to_blk_status(int errno)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(blk_errors); i++) {
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if (blk_errors[i].errno == errno)
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return (__force blk_status_t)i;
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}
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return BLK_STS_IOERR;
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}
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EXPORT_SYMBOL_GPL(errno_to_blk_status);
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int blk_status_to_errno(blk_status_t status)
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{
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int idx = (__force int)status;
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if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
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return -EIO;
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return blk_errors[idx].errno;
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}
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EXPORT_SYMBOL_GPL(blk_status_to_errno);
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const char *blk_status_to_str(blk_status_t status)
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{
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int idx = (__force int)status;
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if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
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return "<null>";
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return blk_errors[idx].name;
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}
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/**
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* blk_sync_queue - cancel any pending callbacks on a queue
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* @q: the queue
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*
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* Description:
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* The block layer may perform asynchronous callback activity
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* on a queue, such as calling the unplug function after a timeout.
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* A block device may call blk_sync_queue to ensure that any
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* such activity is cancelled, thus allowing it to release resources
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* that the callbacks might use. The caller must already have made sure
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* that its ->submit_bio will not re-add plugging prior to calling
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* this function.
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*
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* This function does not cancel any asynchronous activity arising
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* out of elevator or throttling code. That would require elevator_exit()
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* and blkcg_exit_queue() to be called with queue lock initialized.
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*
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*/
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void blk_sync_queue(struct request_queue *q)
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{
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del_timer_sync(&q->timeout);
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cancel_work_sync(&q->timeout_work);
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}
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EXPORT_SYMBOL(blk_sync_queue);
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/**
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* blk_set_pm_only - increment pm_only counter
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* @q: request queue pointer
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*/
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void blk_set_pm_only(struct request_queue *q)
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{
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atomic_inc(&q->pm_only);
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}
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EXPORT_SYMBOL_GPL(blk_set_pm_only);
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void blk_clear_pm_only(struct request_queue *q)
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{
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int pm_only;
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pm_only = atomic_dec_return(&q->pm_only);
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WARN_ON_ONCE(pm_only < 0);
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if (pm_only == 0)
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wake_up_all(&q->mq_freeze_wq);
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}
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EXPORT_SYMBOL_GPL(blk_clear_pm_only);
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/**
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* blk_put_queue - decrement the request_queue refcount
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* @q: the request_queue structure to decrement the refcount for
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*
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* Decrements the refcount of the request_queue kobject. When this reaches 0
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* we'll have blk_release_queue() called.
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*
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* Context: Any context, but the last reference must not be dropped from
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* atomic context.
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*/
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void blk_put_queue(struct request_queue *q)
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{
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kobject_put(&q->kobj);
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}
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EXPORT_SYMBOL(blk_put_queue);
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void blk_queue_start_drain(struct request_queue *q)
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{
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/*
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* When queue DYING flag is set, we need to block new req
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* entering queue, so we call blk_freeze_queue_start() to
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* prevent I/O from crossing blk_queue_enter().
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*/
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blk_freeze_queue_start(q);
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if (queue_is_mq(q))
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blk_mq_wake_waiters(q);
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/* Make blk_queue_enter() reexamine the DYING flag. */
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wake_up_all(&q->mq_freeze_wq);
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}
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void blk_set_queue_dying(struct request_queue *q)
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{
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blk_queue_flag_set(QUEUE_FLAG_DYING, q);
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blk_queue_start_drain(q);
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}
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EXPORT_SYMBOL_GPL(blk_set_queue_dying);
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/**
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* blk_cleanup_queue - shutdown a request queue
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* @q: request queue to shutdown
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*
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* Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
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* put it. All future requests will be failed immediately with -ENODEV.
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*
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* Context: can sleep
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*/
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void blk_cleanup_queue(struct request_queue *q)
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{
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/* cannot be called from atomic context */
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might_sleep();
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WARN_ON_ONCE(blk_queue_registered(q));
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/* mark @q DYING, no new request or merges will be allowed afterwards */
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blk_set_queue_dying(q);
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blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
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blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
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/*
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* Drain all requests queued before DYING marking. Set DEAD flag to
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* prevent that blk_mq_run_hw_queues() accesses the hardware queues
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* after draining finished.
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*/
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blk_freeze_queue(q);
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blk_queue_flag_set(QUEUE_FLAG_DEAD, q);
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blk_sync_queue(q);
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if (queue_is_mq(q)) {
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blk_mq_cancel_work_sync(q);
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blk_mq_exit_queue(q);
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}
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/*
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* In theory, request pool of sched_tags belongs to request queue.
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* However, the current implementation requires tag_set for freeing
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* requests, so free the pool now.
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*
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* Queue has become frozen, there can't be any in-queue requests, so
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* it is safe to free requests now.
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*/
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mutex_lock(&q->sysfs_lock);
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if (q->elevator)
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blk_mq_sched_free_rqs(q);
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mutex_unlock(&q->sysfs_lock);
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percpu_ref_exit(&q->q_usage_counter);
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/* @q is and will stay empty, shutdown and put */
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blk_put_queue(q);
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}
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EXPORT_SYMBOL(blk_cleanup_queue);
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/**
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* blk_queue_enter() - try to increase q->q_usage_counter
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* @q: request queue pointer
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* @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PM
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*/
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int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
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{
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const bool pm = flags & BLK_MQ_REQ_PM;
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while (!blk_try_enter_queue(q, pm)) {
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if (flags & BLK_MQ_REQ_NOWAIT)
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return -EBUSY;
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/*
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* read pair of barrier in blk_freeze_queue_start(), we need to
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* order reading __PERCPU_REF_DEAD flag of .q_usage_counter and
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* reading .mq_freeze_depth or queue dying flag, otherwise the
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* following wait may never return if the two reads are
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* reordered.
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*/
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smp_rmb();
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wait_event(q->mq_freeze_wq,
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(!q->mq_freeze_depth &&
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blk_pm_resume_queue(pm, q)) ||
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blk_queue_dying(q));
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if (blk_queue_dying(q))
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return -ENODEV;
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}
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return 0;
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}
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int __bio_queue_enter(struct request_queue *q, struct bio *bio)
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{
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while (!blk_try_enter_queue(q, false)) {
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struct gendisk *disk = bio->bi_bdev->bd_disk;
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if (bio->bi_opf & REQ_NOWAIT) {
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if (test_bit(GD_DEAD, &disk->state))
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goto dead;
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bio_wouldblock_error(bio);
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return -EBUSY;
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}
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|
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/*
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* read pair of barrier in blk_freeze_queue_start(), we need to
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* order reading __PERCPU_REF_DEAD flag of .q_usage_counter and
|
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* reading .mq_freeze_depth or queue dying flag, otherwise the
|
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* following wait may never return if the two reads are
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* reordered.
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*/
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smp_rmb();
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wait_event(q->mq_freeze_wq,
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(!q->mq_freeze_depth &&
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blk_pm_resume_queue(false, q)) ||
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test_bit(GD_DEAD, &disk->state));
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if (test_bit(GD_DEAD, &disk->state))
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goto dead;
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}
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|
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return 0;
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dead:
|
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bio_io_error(bio);
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return -ENODEV;
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}
|
|
|
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void blk_queue_exit(struct request_queue *q)
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{
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percpu_ref_put(&q->q_usage_counter);
|
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}
|
|
|
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static void blk_queue_usage_counter_release(struct percpu_ref *ref)
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{
|
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struct request_queue *q =
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container_of(ref, struct request_queue, q_usage_counter);
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|
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wake_up_all(&q->mq_freeze_wq);
|
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}
|
|
|
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static void blk_rq_timed_out_timer(struct timer_list *t)
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{
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struct request_queue *q = from_timer(q, t, timeout);
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|
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kblockd_schedule_work(&q->timeout_work);
|
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}
|
|
|
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static void blk_timeout_work(struct work_struct *work)
|
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{
|
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}
|
|
|
|
struct request_queue *blk_alloc_queue(int node_id, bool alloc_srcu)
|
|
{
|
|
struct request_queue *q;
|
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int ret;
|
|
|
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q = kmem_cache_alloc_node(blk_get_queue_kmem_cache(alloc_srcu),
|
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GFP_KERNEL | __GFP_ZERO, node_id);
|
|
if (!q)
|
|
return NULL;
|
|
|
|
if (alloc_srcu) {
|
|
blk_queue_flag_set(QUEUE_FLAG_HAS_SRCU, q);
|
|
if (init_srcu_struct(q->srcu) != 0)
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|
goto fail_q;
|
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}
|
|
|
|
q->last_merge = NULL;
|
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|
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q->id = ida_simple_get(&blk_queue_ida, 0, 0, GFP_KERNEL);
|
|
if (q->id < 0)
|
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goto fail_srcu;
|
|
|
|
ret = bioset_init(&q->bio_split, BIO_POOL_SIZE, 0, 0);
|
|
if (ret)
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goto fail_id;
|
|
|
|
q->stats = blk_alloc_queue_stats();
|
|
if (!q->stats)
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goto fail_split;
|
|
|
|
q->node = node_id;
|
|
|
|
atomic_set(&q->nr_active_requests_shared_tags, 0);
|
|
|
|
timer_setup(&q->timeout, blk_rq_timed_out_timer, 0);
|
|
INIT_WORK(&q->timeout_work, blk_timeout_work);
|
|
INIT_LIST_HEAD(&q->icq_list);
|
|
#ifdef CONFIG_BLK_CGROUP
|
|
INIT_LIST_HEAD(&q->blkg_list);
|
|
#endif
|
|
|
|
kobject_init(&q->kobj, &blk_queue_ktype);
|
|
|
|
mutex_init(&q->debugfs_mutex);
|
|
mutex_init(&q->sysfs_lock);
|
|
mutex_init(&q->sysfs_dir_lock);
|
|
spin_lock_init(&q->queue_lock);
|
|
|
|
init_waitqueue_head(&q->mq_freeze_wq);
|
|
mutex_init(&q->mq_freeze_lock);
|
|
|
|
/*
|
|
* Init percpu_ref in atomic mode so that it's faster to shutdown.
|
|
* See blk_register_queue() for details.
|
|
*/
|
|
if (percpu_ref_init(&q->q_usage_counter,
|
|
blk_queue_usage_counter_release,
|
|
PERCPU_REF_INIT_ATOMIC, GFP_KERNEL))
|
|
goto fail_stats;
|
|
|
|
if (blkcg_init_queue(q))
|
|
goto fail_ref;
|
|
|
|
blk_queue_dma_alignment(q, 511);
|
|
blk_set_default_limits(&q->limits);
|
|
q->nr_requests = BLKDEV_DEFAULT_RQ;
|
|
|
|
return q;
|
|
|
|
fail_ref:
|
|
percpu_ref_exit(&q->q_usage_counter);
|
|
fail_stats:
|
|
blk_free_queue_stats(q->stats);
|
|
fail_split:
|
|
bioset_exit(&q->bio_split);
|
|
fail_id:
|
|
ida_simple_remove(&blk_queue_ida, q->id);
|
|
fail_srcu:
|
|
if (alloc_srcu)
|
|
cleanup_srcu_struct(q->srcu);
|
|
fail_q:
|
|
kmem_cache_free(blk_get_queue_kmem_cache(alloc_srcu), q);
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* blk_get_queue - increment the request_queue refcount
|
|
* @q: the request_queue structure to increment the refcount for
|
|
*
|
|
* Increment the refcount of the request_queue kobject.
|
|
*
|
|
* Context: Any context.
|
|
*/
|
|
bool blk_get_queue(struct request_queue *q)
|
|
{
|
|
if (likely(!blk_queue_dying(q))) {
|
|
__blk_get_queue(q);
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL(blk_get_queue);
|
|
|
|
static void handle_bad_sector(struct bio *bio, sector_t maxsector)
|
|
{
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
pr_info_ratelimited("%s: attempt to access beyond end of device\n"
|
|
"%s: rw=%d, want=%llu, limit=%llu\n",
|
|
current->comm,
|
|
bio_devname(bio, b), bio->bi_opf,
|
|
bio_end_sector(bio), maxsector);
|
|
}
|
|
|
|
#ifdef CONFIG_FAIL_MAKE_REQUEST
|
|
|
|
static DECLARE_FAULT_ATTR(fail_make_request);
|
|
|
|
static int __init setup_fail_make_request(char *str)
|
|
{
|
|
return setup_fault_attr(&fail_make_request, str);
|
|
}
|
|
__setup("fail_make_request=", setup_fail_make_request);
|
|
|
|
bool should_fail_request(struct block_device *part, unsigned int bytes)
|
|
{
|
|
return part->bd_make_it_fail && should_fail(&fail_make_request, bytes);
|
|
}
|
|
|
|
static int __init fail_make_request_debugfs(void)
|
|
{
|
|
struct dentry *dir = fault_create_debugfs_attr("fail_make_request",
|
|
NULL, &fail_make_request);
|
|
|
|
return PTR_ERR_OR_ZERO(dir);
|
|
}
|
|
|
|
late_initcall(fail_make_request_debugfs);
|
|
#endif /* CONFIG_FAIL_MAKE_REQUEST */
|
|
|
|
static inline bool bio_check_ro(struct bio *bio)
|
|
{
|
|
if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) {
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
|
|
return false;
|
|
|
|
WARN_ONCE(1,
|
|
"Trying to write to read-only block-device %s (partno %d)\n",
|
|
bio_devname(bio, b), bio->bi_bdev->bd_partno);
|
|
/* Older lvm-tools actually trigger this */
|
|
return false;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static noinline int should_fail_bio(struct bio *bio)
|
|
{
|
|
if (should_fail_request(bdev_whole(bio->bi_bdev), bio->bi_iter.bi_size))
|
|
return -EIO;
|
|
return 0;
|
|
}
|
|
ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO);
|
|
|
|
/*
|
|
* Check whether this bio extends beyond the end of the device or partition.
|
|
* This may well happen - the kernel calls bread() without checking the size of
|
|
* the device, e.g., when mounting a file system.
|
|
*/
|
|
static inline int bio_check_eod(struct bio *bio)
|
|
{
|
|
sector_t maxsector = bdev_nr_sectors(bio->bi_bdev);
|
|
unsigned int nr_sectors = bio_sectors(bio);
|
|
|
|
if (nr_sectors && maxsector &&
|
|
(nr_sectors > maxsector ||
|
|
bio->bi_iter.bi_sector > maxsector - nr_sectors)) {
|
|
handle_bad_sector(bio, maxsector);
|
|
return -EIO;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Remap block n of partition p to block n+start(p) of the disk.
|
|
*/
|
|
static int blk_partition_remap(struct bio *bio)
|
|
{
|
|
struct block_device *p = bio->bi_bdev;
|
|
|
|
if (unlikely(should_fail_request(p, bio->bi_iter.bi_size)))
|
|
return -EIO;
|
|
if (bio_sectors(bio)) {
|
|
bio->bi_iter.bi_sector += p->bd_start_sect;
|
|
trace_block_bio_remap(bio, p->bd_dev,
|
|
bio->bi_iter.bi_sector -
|
|
p->bd_start_sect);
|
|
}
|
|
bio_set_flag(bio, BIO_REMAPPED);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Check write append to a zoned block device.
|
|
*/
|
|
static inline blk_status_t blk_check_zone_append(struct request_queue *q,
|
|
struct bio *bio)
|
|
{
|
|
sector_t pos = bio->bi_iter.bi_sector;
|
|
int nr_sectors = bio_sectors(bio);
|
|
|
|
/* Only applicable to zoned block devices */
|
|
if (!blk_queue_is_zoned(q))
|
|
return BLK_STS_NOTSUPP;
|
|
|
|
/* The bio sector must point to the start of a sequential zone */
|
|
if (pos & (blk_queue_zone_sectors(q) - 1) ||
|
|
!blk_queue_zone_is_seq(q, pos))
|
|
return BLK_STS_IOERR;
|
|
|
|
/*
|
|
* Not allowed to cross zone boundaries. Otherwise, the BIO will be
|
|
* split and could result in non-contiguous sectors being written in
|
|
* different zones.
|
|
*/
|
|
if (nr_sectors > q->limits.chunk_sectors)
|
|
return BLK_STS_IOERR;
|
|
|
|
/* Make sure the BIO is small enough and will not get split */
|
|
if (nr_sectors > q->limits.max_zone_append_sectors)
|
|
return BLK_STS_IOERR;
|
|
|
|
bio->bi_opf |= REQ_NOMERGE;
|
|
|
|
return BLK_STS_OK;
|
|
}
|
|
|
|
noinline_for_stack bool submit_bio_checks(struct bio *bio)
|
|
{
|
|
struct block_device *bdev = bio->bi_bdev;
|
|
struct request_queue *q = bdev_get_queue(bdev);
|
|
blk_status_t status = BLK_STS_IOERR;
|
|
struct blk_plug *plug;
|
|
|
|
might_sleep();
|
|
|
|
plug = blk_mq_plug(q, bio);
|
|
if (plug && plug->nowait)
|
|
bio->bi_opf |= REQ_NOWAIT;
|
|
|
|
/*
|
|
* For a REQ_NOWAIT based request, return -EOPNOTSUPP
|
|
* if queue does not support NOWAIT.
|
|
*/
|
|
if ((bio->bi_opf & REQ_NOWAIT) && !blk_queue_nowait(q))
|
|
goto not_supported;
|
|
|
|
if (should_fail_bio(bio))
|
|
goto end_io;
|
|
if (unlikely(bio_check_ro(bio)))
|
|
goto end_io;
|
|
if (!bio_flagged(bio, BIO_REMAPPED)) {
|
|
if (unlikely(bio_check_eod(bio)))
|
|
goto end_io;
|
|
if (bdev->bd_partno && unlikely(blk_partition_remap(bio)))
|
|
goto end_io;
|
|
}
|
|
|
|
/*
|
|
* Filter flush bio's early so that bio based drivers without flush
|
|
* support don't have to worry about them.
|
|
*/
|
|
if (op_is_flush(bio->bi_opf) &&
|
|
!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
|
|
bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);
|
|
if (!bio_sectors(bio)) {
|
|
status = BLK_STS_OK;
|
|
goto end_io;
|
|
}
|
|
}
|
|
|
|
if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
|
|
bio_clear_polled(bio);
|
|
|
|
switch (bio_op(bio)) {
|
|
case REQ_OP_DISCARD:
|
|
if (!blk_queue_discard(q))
|
|
goto not_supported;
|
|
break;
|
|
case REQ_OP_SECURE_ERASE:
|
|
if (!blk_queue_secure_erase(q))
|
|
goto not_supported;
|
|
break;
|
|
case REQ_OP_WRITE_SAME:
|
|
if (!q->limits.max_write_same_sectors)
|
|
goto not_supported;
|
|
break;
|
|
case REQ_OP_ZONE_APPEND:
|
|
status = blk_check_zone_append(q, bio);
|
|
if (status != BLK_STS_OK)
|
|
goto end_io;
|
|
break;
|
|
case REQ_OP_ZONE_RESET:
|
|
case REQ_OP_ZONE_OPEN:
|
|
case REQ_OP_ZONE_CLOSE:
|
|
case REQ_OP_ZONE_FINISH:
|
|
if (!blk_queue_is_zoned(q))
|
|
goto not_supported;
|
|
break;
|
|
case REQ_OP_ZONE_RESET_ALL:
|
|
if (!blk_queue_is_zoned(q) || !blk_queue_zone_resetall(q))
|
|
goto not_supported;
|
|
break;
|
|
case REQ_OP_WRITE_ZEROES:
|
|
if (!q->limits.max_write_zeroes_sectors)
|
|
goto not_supported;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
if (blk_throtl_bio(bio))
|
|
return false;
|
|
|
|
blk_cgroup_bio_start(bio);
|
|
blkcg_bio_issue_init(bio);
|
|
|
|
if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) {
|
|
trace_block_bio_queue(bio);
|
|
/* Now that enqueuing has been traced, we need to trace
|
|
* completion as well.
|
|
*/
|
|
bio_set_flag(bio, BIO_TRACE_COMPLETION);
|
|
}
|
|
return true;
|
|
|
|
not_supported:
|
|
status = BLK_STS_NOTSUPP;
|
|
end_io:
|
|
bio->bi_status = status;
|
|
bio_endio(bio);
|
|
return false;
|
|
}
|
|
|
|
static void __submit_bio_fops(struct gendisk *disk, struct bio *bio)
|
|
{
|
|
if (blk_crypto_bio_prep(&bio)) {
|
|
if (likely(bio_queue_enter(bio) == 0)) {
|
|
disk->fops->submit_bio(bio);
|
|
blk_queue_exit(disk->queue);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void __submit_bio(struct bio *bio)
|
|
{
|
|
struct gendisk *disk = bio->bi_bdev->bd_disk;
|
|
|
|
if (unlikely(!submit_bio_checks(bio)))
|
|
return;
|
|
|
|
if (!disk->fops->submit_bio)
|
|
blk_mq_submit_bio(bio);
|
|
else
|
|
__submit_bio_fops(disk, bio);
|
|
}
|
|
|
|
/*
|
|
* The loop in this function may be a bit non-obvious, and so deserves some
|
|
* explanation:
|
|
*
|
|
* - Before entering the loop, bio->bi_next is NULL (as all callers ensure
|
|
* that), so we have a list with a single bio.
|
|
* - We pretend that we have just taken it off a longer list, so we assign
|
|
* bio_list to a pointer to the bio_list_on_stack, thus initialising the
|
|
* bio_list of new bios to be added. ->submit_bio() may indeed add some more
|
|
* bios through a recursive call to submit_bio_noacct. If it did, we find a
|
|
* non-NULL value in bio_list and re-enter the loop from the top.
|
|
* - In this case we really did just take the bio of the top of the list (no
|
|
* pretending) and so remove it from bio_list, and call into ->submit_bio()
|
|
* again.
|
|
*
|
|
* bio_list_on_stack[0] contains bios submitted by the current ->submit_bio.
|
|
* bio_list_on_stack[1] contains bios that were submitted before the current
|
|
* ->submit_bio_bio, but that haven't been processed yet.
|
|
*/
|
|
static void __submit_bio_noacct(struct bio *bio)
|
|
{
|
|
struct bio_list bio_list_on_stack[2];
|
|
|
|
BUG_ON(bio->bi_next);
|
|
|
|
bio_list_init(&bio_list_on_stack[0]);
|
|
current->bio_list = bio_list_on_stack;
|
|
|
|
do {
|
|
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
|
|
struct bio_list lower, same;
|
|
|
|
/*
|
|
* Create a fresh bio_list for all subordinate requests.
|
|
*/
|
|
bio_list_on_stack[1] = bio_list_on_stack[0];
|
|
bio_list_init(&bio_list_on_stack[0]);
|
|
|
|
__submit_bio(bio);
|
|
|
|
/*
|
|
* Sort new bios into those for a lower level and those for the
|
|
* same level.
|
|
*/
|
|
bio_list_init(&lower);
|
|
bio_list_init(&same);
|
|
while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL)
|
|
if (q == bdev_get_queue(bio->bi_bdev))
|
|
bio_list_add(&same, bio);
|
|
else
|
|
bio_list_add(&lower, bio);
|
|
|
|
/*
|
|
* Now assemble so we handle the lowest level first.
|
|
*/
|
|
bio_list_merge(&bio_list_on_stack[0], &lower);
|
|
bio_list_merge(&bio_list_on_stack[0], &same);
|
|
bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);
|
|
} while ((bio = bio_list_pop(&bio_list_on_stack[0])));
|
|
|
|
current->bio_list = NULL;
|
|
}
|
|
|
|
static void __submit_bio_noacct_mq(struct bio *bio)
|
|
{
|
|
struct bio_list bio_list[2] = { };
|
|
|
|
current->bio_list = bio_list;
|
|
|
|
do {
|
|
__submit_bio(bio);
|
|
} while ((bio = bio_list_pop(&bio_list[0])));
|
|
|
|
current->bio_list = NULL;
|
|
}
|
|
|
|
/**
|
|
* submit_bio_noacct - re-submit a bio to the block device layer for I/O
|
|
* @bio: The bio describing the location in memory and on the device.
|
|
*
|
|
* This is a version of submit_bio() that shall only be used for I/O that is
|
|
* resubmitted to lower level drivers by stacking block drivers. All file
|
|
* systems and other upper level users of the block layer should use
|
|
* submit_bio() instead.
|
|
*/
|
|
void submit_bio_noacct(struct bio *bio)
|
|
{
|
|
/*
|
|
* We only want one ->submit_bio to be active at a time, else stack
|
|
* usage with stacked devices could be a problem. Use current->bio_list
|
|
* to collect a list of requests submited by a ->submit_bio method while
|
|
* it is active, and then process them after it returned.
|
|
*/
|
|
if (current->bio_list)
|
|
bio_list_add(¤t->bio_list[0], bio);
|
|
else if (!bio->bi_bdev->bd_disk->fops->submit_bio)
|
|
__submit_bio_noacct_mq(bio);
|
|
else
|
|
__submit_bio_noacct(bio);
|
|
}
|
|
EXPORT_SYMBOL(submit_bio_noacct);
|
|
|
|
/**
|
|
* submit_bio - submit a bio to the block device layer for I/O
|
|
* @bio: The &struct bio which describes the I/O
|
|
*
|
|
* submit_bio() is used to submit I/O requests to block devices. It is passed a
|
|
* fully set up &struct bio that describes the I/O that needs to be done. The
|
|
* bio will be send to the device described by the bi_bdev field.
|
|
*
|
|
* The success/failure status of the request, along with notification of
|
|
* completion, is delivered asynchronously through the ->bi_end_io() callback
|
|
* in @bio. The bio must NOT be touched by thecaller until ->bi_end_io() has
|
|
* been called.
|
|
*/
|
|
void submit_bio(struct bio *bio)
|
|
{
|
|
if (blkcg_punt_bio_submit(bio))
|
|
return;
|
|
|
|
/*
|
|
* If it's a regular read/write or a barrier with data attached,
|
|
* go through the normal accounting stuff before submission.
|
|
*/
|
|
if (bio_has_data(bio)) {
|
|
unsigned int count;
|
|
|
|
if (unlikely(bio_op(bio) == REQ_OP_WRITE_SAME))
|
|
count = queue_logical_block_size(
|
|
bdev_get_queue(bio->bi_bdev)) >> 9;
|
|
else
|
|
count = bio_sectors(bio);
|
|
|
|
if (op_is_write(bio_op(bio))) {
|
|
count_vm_events(PGPGOUT, count);
|
|
} else {
|
|
task_io_account_read(bio->bi_iter.bi_size);
|
|
count_vm_events(PGPGIN, count);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we're reading data that is part of the userspace workingset, count
|
|
* submission time as memory stall. When the device is congested, or
|
|
* the submitting cgroup IO-throttled, submission can be a significant
|
|
* part of overall IO time.
|
|
*/
|
|
if (unlikely(bio_op(bio) == REQ_OP_READ &&
|
|
bio_flagged(bio, BIO_WORKINGSET))) {
|
|
unsigned long pflags;
|
|
|
|
psi_memstall_enter(&pflags);
|
|
submit_bio_noacct(bio);
|
|
psi_memstall_leave(&pflags);
|
|
return;
|
|
}
|
|
|
|
submit_bio_noacct(bio);
|
|
}
|
|
EXPORT_SYMBOL(submit_bio);
|
|
|
|
/**
|
|
* bio_poll - poll for BIO completions
|
|
* @bio: bio to poll for
|
|
* @iob: batches of IO
|
|
* @flags: BLK_POLL_* flags that control the behavior
|
|
*
|
|
* Poll for completions on queue associated with the bio. Returns number of
|
|
* completed entries found.
|
|
*
|
|
* Note: the caller must either be the context that submitted @bio, or
|
|
* be in a RCU critical section to prevent freeing of @bio.
|
|
*/
|
|
int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags)
|
|
{
|
|
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
|
|
blk_qc_t cookie = READ_ONCE(bio->bi_cookie);
|
|
int ret;
|
|
|
|
if (cookie == BLK_QC_T_NONE ||
|
|
!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
|
|
return 0;
|
|
|
|
if (current->plug)
|
|
blk_flush_plug(current->plug, false);
|
|
|
|
if (blk_queue_enter(q, BLK_MQ_REQ_NOWAIT))
|
|
return 0;
|
|
if (WARN_ON_ONCE(!queue_is_mq(q)))
|
|
ret = 0; /* not yet implemented, should not happen */
|
|
else
|
|
ret = blk_mq_poll(q, cookie, iob, flags);
|
|
blk_queue_exit(q);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(bio_poll);
|
|
|
|
/*
|
|
* Helper to implement file_operations.iopoll. Requires the bio to be stored
|
|
* in iocb->private, and cleared before freeing the bio.
|
|
*/
|
|
int iocb_bio_iopoll(struct kiocb *kiocb, struct io_comp_batch *iob,
|
|
unsigned int flags)
|
|
{
|
|
struct bio *bio;
|
|
int ret = 0;
|
|
|
|
/*
|
|
* Note: the bio cache only uses SLAB_TYPESAFE_BY_RCU, so bio can
|
|
* point to a freshly allocated bio at this point. If that happens
|
|
* we have a few cases to consider:
|
|
*
|
|
* 1) the bio is beeing initialized and bi_bdev is NULL. We can just
|
|
* simply nothing in this case
|
|
* 2) the bio points to a not poll enabled device. bio_poll will catch
|
|
* this and return 0
|
|
* 3) the bio points to a poll capable device, including but not
|
|
* limited to the one that the original bio pointed to. In this
|
|
* case we will call into the actual poll method and poll for I/O,
|
|
* even if we don't need to, but it won't cause harm either.
|
|
*
|
|
* For cases 2) and 3) above the RCU grace period ensures that bi_bdev
|
|
* is still allocated. Because partitions hold a reference to the whole
|
|
* device bdev and thus disk, the disk is also still valid. Grabbing
|
|
* a reference to the queue in bio_poll() ensures the hctxs and requests
|
|
* are still valid as well.
|
|
*/
|
|
rcu_read_lock();
|
|
bio = READ_ONCE(kiocb->private);
|
|
if (bio && bio->bi_bdev)
|
|
ret = bio_poll(bio, iob, flags);
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(iocb_bio_iopoll);
|
|
|
|
void update_io_ticks(struct block_device *part, unsigned long now, bool end)
|
|
{
|
|
unsigned long stamp;
|
|
again:
|
|
stamp = READ_ONCE(part->bd_stamp);
|
|
if (unlikely(time_after(now, stamp))) {
|
|
if (likely(cmpxchg(&part->bd_stamp, stamp, now) == stamp))
|
|
__part_stat_add(part, io_ticks, end ? now - stamp : 1);
|
|
}
|
|
if (part->bd_partno) {
|
|
part = bdev_whole(part);
|
|
goto again;
|
|
}
|
|
}
|
|
|
|
static unsigned long __part_start_io_acct(struct block_device *part,
|
|
unsigned int sectors, unsigned int op,
|
|
unsigned long start_time)
|
|
{
|
|
const int sgrp = op_stat_group(op);
|
|
|
|
part_stat_lock();
|
|
update_io_ticks(part, start_time, false);
|
|
part_stat_inc(part, ios[sgrp]);
|
|
part_stat_add(part, sectors[sgrp], sectors);
|
|
part_stat_local_inc(part, in_flight[op_is_write(op)]);
|
|
part_stat_unlock();
|
|
|
|
return start_time;
|
|
}
|
|
|
|
/**
|
|
* bio_start_io_acct_time - start I/O accounting for bio based drivers
|
|
* @bio: bio to start account for
|
|
* @start_time: start time that should be passed back to bio_end_io_acct().
|
|
*/
|
|
void bio_start_io_acct_time(struct bio *bio, unsigned long start_time)
|
|
{
|
|
__part_start_io_acct(bio->bi_bdev, bio_sectors(bio),
|
|
bio_op(bio), start_time);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bio_start_io_acct_time);
|
|
|
|
/**
|
|
* bio_start_io_acct - start I/O accounting for bio based drivers
|
|
* @bio: bio to start account for
|
|
*
|
|
* Returns the start time that should be passed back to bio_end_io_acct().
|
|
*/
|
|
unsigned long bio_start_io_acct(struct bio *bio)
|
|
{
|
|
return __part_start_io_acct(bio->bi_bdev, bio_sectors(bio),
|
|
bio_op(bio), jiffies);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bio_start_io_acct);
|
|
|
|
unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
|
|
unsigned int op)
|
|
{
|
|
return __part_start_io_acct(disk->part0, sectors, op, jiffies);
|
|
}
|
|
EXPORT_SYMBOL(disk_start_io_acct);
|
|
|
|
static void __part_end_io_acct(struct block_device *part, unsigned int op,
|
|
unsigned long start_time)
|
|
{
|
|
const int sgrp = op_stat_group(op);
|
|
unsigned long now = READ_ONCE(jiffies);
|
|
unsigned long duration = now - start_time;
|
|
|
|
part_stat_lock();
|
|
update_io_ticks(part, now, true);
|
|
part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration));
|
|
part_stat_local_dec(part, in_flight[op_is_write(op)]);
|
|
part_stat_unlock();
|
|
}
|
|
|
|
void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
|
|
struct block_device *orig_bdev)
|
|
{
|
|
__part_end_io_acct(orig_bdev, bio_op(bio), start_time);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped);
|
|
|
|
void disk_end_io_acct(struct gendisk *disk, unsigned int op,
|
|
unsigned long start_time)
|
|
{
|
|
__part_end_io_acct(disk->part0, op, start_time);
|
|
}
|
|
EXPORT_SYMBOL(disk_end_io_acct);
|
|
|
|
/**
|
|
* blk_lld_busy - Check if underlying low-level drivers of a device are busy
|
|
* @q : the queue of the device being checked
|
|
*
|
|
* Description:
|
|
* Check if underlying low-level drivers of a device are busy.
|
|
* If the drivers want to export their busy state, they must set own
|
|
* exporting function using blk_queue_lld_busy() first.
|
|
*
|
|
* Basically, this function is used only by request stacking drivers
|
|
* to stop dispatching requests to underlying devices when underlying
|
|
* devices are busy. This behavior helps more I/O merging on the queue
|
|
* of the request stacking driver and prevents I/O throughput regression
|
|
* on burst I/O load.
|
|
*
|
|
* Return:
|
|
* 0 - Not busy (The request stacking driver should dispatch request)
|
|
* 1 - Busy (The request stacking driver should stop dispatching request)
|
|
*/
|
|
int blk_lld_busy(struct request_queue *q)
|
|
{
|
|
if (queue_is_mq(q) && q->mq_ops->busy)
|
|
return q->mq_ops->busy(q);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_lld_busy);
|
|
|
|
int kblockd_schedule_work(struct work_struct *work)
|
|
{
|
|
return queue_work(kblockd_workqueue, work);
|
|
}
|
|
EXPORT_SYMBOL(kblockd_schedule_work);
|
|
|
|
int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork,
|
|
unsigned long delay)
|
|
{
|
|
return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay);
|
|
}
|
|
EXPORT_SYMBOL(kblockd_mod_delayed_work_on);
|
|
|
|
void blk_start_plug_nr_ios(struct blk_plug *plug, unsigned short nr_ios)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
|
|
/*
|
|
* If this is a nested plug, don't actually assign it.
|
|
*/
|
|
if (tsk->plug)
|
|
return;
|
|
|
|
plug->mq_list = NULL;
|
|
plug->cached_rq = NULL;
|
|
plug->nr_ios = min_t(unsigned short, nr_ios, BLK_MAX_REQUEST_COUNT);
|
|
plug->rq_count = 0;
|
|
plug->multiple_queues = false;
|
|
plug->has_elevator = false;
|
|
plug->nowait = false;
|
|
INIT_LIST_HEAD(&plug->cb_list);
|
|
|
|
/*
|
|
* Store ordering should not be needed here, since a potential
|
|
* preempt will imply a full memory barrier
|
|
*/
|
|
tsk->plug = plug;
|
|
}
|
|
|
|
/**
|
|
* blk_start_plug - initialize blk_plug and track it inside the task_struct
|
|
* @plug: The &struct blk_plug that needs to be initialized
|
|
*
|
|
* Description:
|
|
* blk_start_plug() indicates to the block layer an intent by the caller
|
|
* to submit multiple I/O requests in a batch. The block layer may use
|
|
* this hint to defer submitting I/Os from the caller until blk_finish_plug()
|
|
* is called. However, the block layer may choose to submit requests
|
|
* before a call to blk_finish_plug() if the number of queued I/Os
|
|
* exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than
|
|
* %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if
|
|
* the task schedules (see below).
|
|
*
|
|
* Tracking blk_plug inside the task_struct will help with auto-flushing the
|
|
* pending I/O should the task end up blocking between blk_start_plug() and
|
|
* blk_finish_plug(). This is important from a performance perspective, but
|
|
* also ensures that we don't deadlock. For instance, if the task is blocking
|
|
* for a memory allocation, memory reclaim could end up wanting to free a
|
|
* page belonging to that request that is currently residing in our private
|
|
* plug. By flushing the pending I/O when the process goes to sleep, we avoid
|
|
* this kind of deadlock.
|
|
*/
|
|
void blk_start_plug(struct blk_plug *plug)
|
|
{
|
|
blk_start_plug_nr_ios(plug, 1);
|
|
}
|
|
EXPORT_SYMBOL(blk_start_plug);
|
|
|
|
static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
|
|
{
|
|
LIST_HEAD(callbacks);
|
|
|
|
while (!list_empty(&plug->cb_list)) {
|
|
list_splice_init(&plug->cb_list, &callbacks);
|
|
|
|
while (!list_empty(&callbacks)) {
|
|
struct blk_plug_cb *cb = list_first_entry(&callbacks,
|
|
struct blk_plug_cb,
|
|
list);
|
|
list_del(&cb->list);
|
|
cb->callback(cb, from_schedule);
|
|
}
|
|
}
|
|
}
|
|
|
|
struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data,
|
|
int size)
|
|
{
|
|
struct blk_plug *plug = current->plug;
|
|
struct blk_plug_cb *cb;
|
|
|
|
if (!plug)
|
|
return NULL;
|
|
|
|
list_for_each_entry(cb, &plug->cb_list, list)
|
|
if (cb->callback == unplug && cb->data == data)
|
|
return cb;
|
|
|
|
/* Not currently on the callback list */
|
|
BUG_ON(size < sizeof(*cb));
|
|
cb = kzalloc(size, GFP_ATOMIC);
|
|
if (cb) {
|
|
cb->data = data;
|
|
cb->callback = unplug;
|
|
list_add(&cb->list, &plug->cb_list);
|
|
}
|
|
return cb;
|
|
}
|
|
EXPORT_SYMBOL(blk_check_plugged);
|
|
|
|
void blk_flush_plug(struct blk_plug *plug, bool from_schedule)
|
|
{
|
|
if (!list_empty(&plug->cb_list))
|
|
flush_plug_callbacks(plug, from_schedule);
|
|
if (!rq_list_empty(plug->mq_list))
|
|
blk_mq_flush_plug_list(plug, from_schedule);
|
|
/*
|
|
* Unconditionally flush out cached requests, even if the unplug
|
|
* event came from schedule. Since we know hold references to the
|
|
* queue for cached requests, we don't want a blocked task holding
|
|
* up a queue freeze/quiesce event.
|
|
*/
|
|
if (unlikely(!rq_list_empty(plug->cached_rq)))
|
|
blk_mq_free_plug_rqs(plug);
|
|
}
|
|
|
|
/**
|
|
* blk_finish_plug - mark the end of a batch of submitted I/O
|
|
* @plug: The &struct blk_plug passed to blk_start_plug()
|
|
*
|
|
* Description:
|
|
* Indicate that a batch of I/O submissions is complete. This function
|
|
* must be paired with an initial call to blk_start_plug(). The intent
|
|
* is to allow the block layer to optimize I/O submission. See the
|
|
* documentation for blk_start_plug() for more information.
|
|
*/
|
|
void blk_finish_plug(struct blk_plug *plug)
|
|
{
|
|
if (plug == current->plug) {
|
|
blk_flush_plug(plug, false);
|
|
current->plug = NULL;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_finish_plug);
|
|
|
|
void blk_io_schedule(void)
|
|
{
|
|
/* Prevent hang_check timer from firing at us during very long I/O */
|
|
unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2;
|
|
|
|
if (timeout)
|
|
io_schedule_timeout(timeout);
|
|
else
|
|
io_schedule();
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_io_schedule);
|
|
|
|
int __init blk_dev_init(void)
|
|
{
|
|
BUILD_BUG_ON(REQ_OP_LAST >= (1 << REQ_OP_BITS));
|
|
BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
|
|
sizeof_field(struct request, cmd_flags));
|
|
BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
|
|
sizeof_field(struct bio, bi_opf));
|
|
BUILD_BUG_ON(ALIGN(offsetof(struct request_queue, srcu),
|
|
__alignof__(struct request_queue)) !=
|
|
sizeof(struct request_queue));
|
|
|
|
/* used for unplugging and affects IO latency/throughput - HIGHPRI */
|
|
kblockd_workqueue = alloc_workqueue("kblockd",
|
|
WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
|
|
if (!kblockd_workqueue)
|
|
panic("Failed to create kblockd\n");
|
|
|
|
blk_requestq_cachep = kmem_cache_create("request_queue",
|
|
sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
|
|
|
|
blk_requestq_srcu_cachep = kmem_cache_create("request_queue_srcu",
|
|
sizeof(struct request_queue) +
|
|
sizeof(struct srcu_struct), 0, SLAB_PANIC, NULL);
|
|
|
|
blk_debugfs_root = debugfs_create_dir("block", NULL);
|
|
|
|
return 0;
|
|
}
|