// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 1994, Karl Keyte: Added support for disk statistics
* Elevator latency, (C) 2000 Andrea Arcangeli <[email protected]> SuSE
* Queue request tables / lock, selectable elevator, Jens Axboe <[email protected]>
* kernel-doc documentation started by NeilBrown <[email protected]>
* - July2000
* bio rewrite, highmem i/o, etc, Jens Axboe <[email protected]> - may 2001
*/
/*
* This handles all read/write requests to block devices
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/blk-pm.h>
#include <linux/blk-integrity.h>
#include <linux/highmem.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/kernel_stat.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/fault-inject.h>
#include <linux/list_sort.h>
#include <linux/delay.h>
#include <linux/ratelimit.h>
#include <linux/pm_runtime.h>
#include <linux/t10-pi.h>
#include <linux/debugfs.h>
#include <linux/bpf.h>
#include <linux/part_stat.h>
#include <linux/sched/sysctl.h>
#include <linux/blk-crypto.h>
#define CREATE_TRACE_POINTS
#include <trace/events/block.h>
#include "blk.h"
#include "blk-mq-sched.h"
#include "blk-pm.h"
#include "blk-cgroup.h"
#include "blk-throttle.h"
#include "blk-ioprio.h"
struct dentry *blk_debugfs_root;
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_split);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert);
static DEFINE_IDA(blk_queue_ida);
/*
* For queue allocation
*/
static struct kmem_cache *blk_requestq_cachep;
/*
* Controlling structure to kblockd
*/
static struct workqueue_struct *kblockd_workqueue;
/**
* blk_queue_flag_set - atomically set a queue flag
* @flag: flag to be set
* @q: request queue
*/
void blk_queue_flag_set(unsigned int flag, struct request_queue *q)
{
set_bit(flag, &q->queue_flags);
}
EXPORT_SYMBOL(blk_queue_flag_set);
/**
* blk_queue_flag_clear - atomically clear a queue flag
* @flag: flag to be cleared
* @q: request queue
*/
void blk_queue_flag_clear(unsigned int flag, struct request_queue *q)
{
clear_bit(flag, &q->queue_flags);
}
EXPORT_SYMBOL(blk_queue_flag_clear);
#define REQ_OP_NAME(name) [REQ_OP_##name] = #name
static const char *const blk_op_name[] = {
REQ_OP_NAME(READ),
REQ_OP_NAME(WRITE),
REQ_OP_NAME(FLUSH),
REQ_OP_NAME(DISCARD),
REQ_OP_NAME(SECURE_ERASE),
REQ_OP_NAME(ZONE_RESET),
REQ_OP_NAME(ZONE_RESET_ALL),
REQ_OP_NAME(ZONE_OPEN),
REQ_OP_NAME(ZONE_CLOSE),
REQ_OP_NAME(ZONE_FINISH),
REQ_OP_NAME(ZONE_APPEND),
REQ_OP_NAME(WRITE_ZEROES),
REQ_OP_NAME(DRV_IN),
REQ_OP_NAME(DRV_OUT),
};
#undef REQ_OP_NAME
/**
* blk_op_str - Return string XXX in the REQ_OP_XXX.
* @op: REQ_OP_XXX.
*
* Description: Centralize block layer function to convert REQ_OP_XXX into
* string format. Useful in the debugging and tracing bio or request. For
* invalid REQ_OP_XXX it returns string "UNKNOWN".
*/
inline const char *blk_op_str(enum req_op op)
{
const char *op_str = "UNKNOWN";
if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op])
op_str = blk_op_name[op];
return op_str;
}
EXPORT_SYMBOL_GPL(blk_op_str);
static const struct {
int errno;
const char *name;
} blk_errors[] = {
[BLK_STS_OK] = { 0, "" },
[BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" },
[BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" },
[BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" },
[BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" },
[BLK_STS_TARGET] = { -EREMOTEIO, "critical target" },
[BLK_STS_RESV_CONFLICT] = { -EBADE, "reservation conflict" },
[BLK_STS_MEDIUM] = { -ENODATA, "critical medium" },
[BLK_STS_PROTECTION] = { -EILSEQ, "protection" },
[BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" },
[BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" },
[BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" },
[BLK_STS_OFFLINE] = { -ENODEV, "device offline" },
/* device mapper special case, should not leak out: */
[BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" },
/* zone device specific errors */
[BLK_STS_ZONE_OPEN_RESOURCE] = { -ETOOMANYREFS, "open zones exceeded" },
[BLK_STS_ZONE_ACTIVE_RESOURCE] = { -EOVERFLOW, "active zones exceeded" },
/* Command duration limit device-side timeout */
[BLK_STS_DURATION_LIMIT] = { -ETIME, "duration limit exceeded" },
[BLK_STS_INVAL] = { -EINVAL, "invalid" },
/* everything else not covered above: */
[BLK_STS_IOERR] = { -EIO, "I/O" },
};
blk_status_t errno_to_blk_status(int errno)
{
int i;
for (i = 0; i < ARRAY_SIZE(blk_errors); i++) {
if (blk_errors[i].errno == errno)
return (__force blk_status_t)i;
}
return BLK_STS_IOERR;
}
EXPORT_SYMBOL_GPL(errno_to_blk_status);
int blk_status_to_errno(blk_status_t status)
{
int idx = (__force int)status;
if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
return -EIO;
return blk_errors[idx].errno;
}
EXPORT_SYMBOL_GPL(blk_status_to_errno);
const char *blk_status_to_str(blk_status_t status)
{
int idx = (__force int)status;
if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
return "<null>";
return blk_errors[idx].name;
}
EXPORT_SYMBOL_GPL(blk_status_to_str);
/**
* blk_sync_queue - cancel any pending callbacks on a queue
* @q: the queue
*
* Description:
* The block layer may perform asynchronous callback activity
* on a queue, such as calling the unplug function after a timeout.
* A block device may call blk_sync_queue to ensure that any
* such activity is cancelled, thus allowing it to release resources
* that the callbacks might use. The caller must already have made sure
* that its ->submit_bio will not re-add plugging prior to calling
* this function.
*
* This function does not cancel any asynchronous activity arising
* out of elevator or throttling code. That would require elevator_exit()
* and blkcg_exit_queue() to be called with queue lock initialized.
*
*/
void blk_sync_queue(struct request_queue *q)
{
del_timer_sync(&q->timeout);
cancel_work_sync(&q->timeout_work);
}
EXPORT_SYMBOL(blk_sync_queue);
/**
* blk_set_pm_only - increment pm_only counter
* @q: request queue pointer
*/
void blk_set_pm_only(struct request_queue *q)
{
atomic_inc(&q->pm_only);
}
EXPORT_SYMBOL_GPL(blk_set_pm_only);
void blk_clear_pm_only(struct request_queue *q)
{
int pm_only;
pm_only = atomic_dec_return(&q->pm_only);
WARN_ON_ONCE(pm_only < 0);
if (pm_only == 0)
wake_up_all(&q->mq_freeze_wq);
}
EXPORT_SYMBOL_GPL(blk_clear_pm_only);
static void blk_free_queue_rcu(struct rcu_head *rcu_head)
{
struct request_queue *q = container_of(rcu_head,
struct request_queue, rcu_head);
percpu_ref_exit(&q->q_usage_counter);
kmem_cache_free(blk_requestq_cachep, q);
}
static void blk_free_queue(struct request_queue *q)
{
blk_free_queue_stats(q->stats);
if (queue_is_mq(q))
blk_mq_release(q);
ida_free(&blk_queue_ida, q->id);
call_rcu(&q->rcu_head, blk_free_queue_rcu);
}
/**
* blk_put_queue - decrement the request_queue refcount
* @q: the request_queue structure to decrement the refcount for
*
* Decrements the refcount of the request_queue and free it when the refcount
* reaches 0.
*/
void blk_put_queue(struct request_queue *q)
{
if (refcount_dec_and_test(&q->refs))
blk_free_queue(q);
}
EXPORT_SYMBOL(blk_put_queue);
void blk_queue_start_drain(struct request_queue *q)
{
/*
* When queue DYING flag is set, we need to block new req
* entering queue, so we call blk_freeze_queue_start() to
* prevent I/O from crossing blk_queue_enter().
*/
blk_freeze_queue_start(q);
if (queue_is_mq(q))
blk_mq_wake_waiters(q);
/* Make blk_queue_enter() reexamine the DYING flag. */
wake_up_all(&q->mq_freeze_wq);
}
/**
* blk_queue_enter() - try to increase q->q_usage_counter
* @q: request queue pointer
* @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PM
*/
int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
{
const bool pm = flags & BLK_MQ_REQ_PM;
while (!blk_try_enter_queue(q, pm)) {
if (flags & BLK_MQ_REQ_NOWAIT)
return -EAGAIN;
/*
* read pair of barrier in blk_freeze_queue_start(), we need to
* order reading __PERCPU_REF_DEAD flag of .q_usage_counter and
* reading .mq_freeze_depth or queue dying flag, otherwise the
* following wait may never return if the two reads are
* reordered.
*/
smp_rmb();
wait_event(q->mq_freeze_wq,
(!q->mq_freeze_depth &&
blk_pm_resume_queue(pm, q)) ||
blk_queue_dying(q));
if (blk_queue_dying(q))
return -ENODEV;
}
return 0;
}
int __bio_queue_enter(struct request_queue *q, struct bio *bio)
{
while (!blk_try_enter_queue(q, false)) {
struct gendisk *disk = bio->bi_bdev->bd_disk;
if (bio->bi_opf & REQ_NOWAIT) {
if (test_bit(GD_DEAD, &disk->state))
goto dead;
bio_wouldblock_error(bio);
return -EAGAIN;
}
/*
* read pair of barrier in blk_freeze_queue_start(), we need to
* order reading __PERCPU_REF_DEAD flag of .q_usage_counter and
* reading .mq_freeze_depth or queue dying flag, otherwise the
* following wait may never return if the two reads are
* reordered.
*/
smp_rmb();
wait_event(q->mq_freeze_wq,
(!q->mq_freeze_depth &&
blk_pm_resume_queue(false, q)) ||
test_bit(GD_DEAD, &disk->state));
if (test_bit(GD_DEAD, &disk->state))
goto dead;
}
return 0;
dead:
bio_io_error(bio);
return -ENODEV;
}
void blk_queue_exit(struct request_queue *q)
{
percpu_ref_put(&q->q_usage_counter);
}
static void blk_queue_usage_counter_release(struct percpu_ref *ref)
{
struct request_queue *q =
container_of(ref, struct request_queue, q_usage_counter);
wake_up_all(&q->mq_freeze_wq);
}
static void blk_rq_timed_out_timer(struct timer_list *t)
{
struct request_queue *q = from_timer(q, t, timeout);
kblockd_schedule_work(&q->timeout_work);
}
static void blk_timeout_work(struct work_struct *work)
{
}
struct request_queue *blk_alloc_queue(struct queue_limits *lim, int node_id)
{
struct request_queue *q;
int error;
q = kmem_cache_alloc_node(blk_requestq_cachep, GFP_KERNEL | __GFP_ZERO,
node_id);
if (!q)
return ERR_PTR(-ENOMEM);
q->last_merge = NULL;
q->id = ida_alloc(&blk_queue_ida, GFP_KERNEL);
if (q->id < 0) {
error = q->id;
goto fail_q;
}
q->stats = blk_alloc_queue_stats();
if (!q->stats) {
error = -ENOMEM;
goto fail_id;
}
error = blk_set_default_limits(lim);
if (error)
goto fail_stats;
q->limits = *lim;
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);
refcount_set(&q->refs, 1);
mutex_init(&q->debugfs_mutex);
mutex_init(&q->sysfs_lock);
mutex_init(&q->sysfs_dir_lock);
mutex_init(&q->limits_lock);
mutex_init(&q->rq_qos_mutex);
spin_lock_init(&q->queue_lock);
init_waitqueue_head(&q->mq_freeze_wq);
mutex_init(&q->mq_freeze_lock);
blkg_init_queue(q);
/*
* Init percpu_ref in atomic mode so that it's faster to shutdown.
* See blk_register_queue() for details.
*/
error = percpu_ref_init(&q->q_usage_counter,
blk_queue_usage_counter_release,
PERCPU_REF_INIT_ATOMIC, GFP_KERNEL);
if (error)
goto fail_stats;
q->nr_requests = BLKDEV_DEFAULT_RQ;
return q;
fail_stats:
blk_free_queue_stats(q->stats);
fail_id:
ida_free(&blk_queue_ida, q->id);
fail_q:
kmem_cache_free(blk_requestq_cachep, q);
return ERR_PTR(error);
}
/**
* 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 (unlikely(blk_queue_dying(q)))
return false;
refcount_inc(&q->refs);
return true;
}
EXPORT_SYMBOL(blk_get_queue);
#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 bdev_test_flag(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 void bio_check_ro(struct bio *bio)
{
if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) {
if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
return;
if (bdev_test_flag(bio->bi_bdev, BD_RO_WARNED))
return;
bdev_set_flag(bio->bi_bdev, BD_RO_WARNED);
/*
* Use ioctl to set underlying disk of raid/dm to read-only
* will trigger this.
*/
pr_warn("Trying to write to read-only block-device %pg\n",
bio->bi_bdev);
}
}
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 &&
(nr_sectors > maxsector ||
bio->bi_iter.bi_sector > maxsector - nr_sectors)) {
pr_info_ratelimited("%s: attempt to access beyond end of device\n"
"%pg: rw=%d, sector=%llu, nr_sectors = %u limit=%llu\n",
current->comm, bio->bi_bdev, bio->bi_opf,
bio->bi_iter.bi_sector, nr_sectors, 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)
{
int nr_sectors = bio_sectors(bio);
/* Only applicable to zoned block devices */
if (!bdev_is_zoned(bio->bi_bdev))
return BLK_STS_NOTSUPP;
/* The bio sector must point to the start of a sequential zone */
if (!bdev_is_zone_start(bio->bi_bdev, bio->bi_iter.bi_sector))
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 > queue_max_zone_append_sectors(q))
return BLK_STS_IOERR;
bio->bi_opf |= REQ_NOMERGE;
return BLK_STS_OK;
}
static void __submit_bio(struct bio *bio)
{
/* If plug is not used, add new plug here to cache nsecs time. */
struct blk_plug plug;
if (unlikely(!blk_crypto_bio_prep(&bio)))
return;
blk_start_plug(&plug);
if (!bdev_test_flag(bio->bi_bdev, BD_HAS_SUBMIT_BIO)) {
blk_mq_submit_bio(bio);
} else if (likely(bio_queue_enter(bio) == 0)) {
struct gendisk *disk = bio->bi_bdev->bd_disk;
disk->fops->submit_bio(bio);
blk_queue_exit(disk->queue);
}
blk_finish_plug(&plug);
}
/*
* 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, 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;
}
void submit_bio_noacct_nocheck(struct bio *bio)
{
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);
}
/*
* 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 (!bdev_test_flag(bio->bi_bdev, BD_HAS_SUBMIT_BIO))
__submit_bio_noacct_mq(bio);
else
__submit_bio_noacct(bio);
}
static blk_status_t blk_validate_atomic_write_op_size(struct request_queue *q,
struct bio *bio)
{
if (bio->bi_iter.bi_size > queue_atomic_write_unit_max_bytes(q))
return BLK_STS_INVAL;
if (bio->bi_iter.bi_size % queue_atomic_write_unit_min_bytes(q))
return BLK_STS_INVAL;
return BLK_STS_OK;
}
/**
* 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)
{
struct block_device *bdev = bio->bi_bdev;
struct request_queue *q = bdev_get_queue(bdev);
blk_status_t status = BLK_STS_IOERR;
might_sleep();
/*
* For a REQ_NOWAIT based request, return -EOPNOTSUPP
* if queue does not support NOWAIT.
*/
if ((bio->bi_opf & REQ_NOWAIT) && !bdev_nowait(bdev))
goto not_supported;
if (should_fail_bio(bio))
goto end_io;
bio_check_ro(bio);
if (!bio_flagged(bio, BIO_REMAPPED)) {
if (unlikely(bio_check_eod(bio)))
goto end_io;
if (bdev_is_partition(bdev) &&
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)) {
if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_WRITE &&
bio_op(bio) != REQ_OP_ZONE_APPEND))
goto end_io;
if (!bdev_write_cache(bdev)) {
bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);
if (!bio_sectors(bio)) {
status = BLK_STS_OK;
goto end_io;
}
}
}
if (!(q->limits.features & BLK_FEAT_POLL) &&
(bio->bi_opf & REQ_POLLED)) {
bio_clear_polled(bio);
goto not_supported;
}
switch (bio_op(bio)) {
case REQ_OP_READ:
break;
case REQ_OP_WRITE:
if (bio->bi_opf & REQ_ATOMIC) {
status = blk_validate_atomic_write_op_size(q, bio);
if (status != BLK_STS_OK)
goto end_io;
}
break;
case REQ_OP_FLUSH:
/*
* REQ_OP_FLUSH can't be submitted through bios, it is only
* synthetized in struct request by the flush state machine.
*/
goto not_supported;
case REQ_OP_DISCARD:
if (!bdev_max_discard_sectors(bdev))
goto not_supported;
break;
case REQ_OP_SECURE_ERASE:
if (!bdev_max_secure_erase_sectors(bdev))
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_WRITE_ZEROES:
if (!q->limits.max_write_zeroes_sectors)
goto not_supported;
break;
case REQ_OP_ZONE_RESET:
case REQ_OP_ZONE_OPEN:
case REQ_OP_ZONE_CLOSE:
case REQ_OP_ZONE_FINISH:
case REQ_OP_ZONE_RESET_ALL:
if (!bdev_is_zoned(bio->bi_bdev))
goto not_supported;
break;
case REQ_OP_DRV_IN:
case REQ_OP_DRV_OUT:
/*
* Driver private operations are only used with passthrough
* requests.
*/
fallthrough;
default:
goto not_supported;
}
if (blk_throtl_bio(bio))
return;
submit_bio_noacct_nocheck(bio);
return;
not_supported:
status = BLK_STS_NOTSUPP;
end_io:
bio->bi_status = status;
bio_endio(bio);
}
EXPORT_SYMBOL(submit_bio_noacct);
static void bio_set_ioprio(struct bio *bio)
{
/* Nobody set ioprio so far? Initialize it based on task's nice value */
if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE)
bio->bi_ioprio = get_current_ioprio();
blkcg_set_ioprio(bio);
}
/**
* 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 the caller until ->bi_end_io() has
* been called.
*/
void submit_bio(struct bio *bio)
{
if (bio_op(bio) == REQ_OP_READ) {
task_io_account_read(bio->bi_iter.bi_size);
count_vm_events(PGPGIN, bio_sectors(bio));
} else if (bio_op(bio) == REQ_OP_WRITE) {
count_vm_events(PGPGOUT, bio_sectors(bio));
}
bio_set_ioprio(bio);
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)
{
blk_qc_t cookie = READ_ONCE(bio->bi_cookie);
struct block_device *bdev;
struct request_queue *q;
int ret = 0;
bdev = READ_ONCE(bio->bi_bdev);
if (!bdev)
return 0;
q = bdev_get_queue(bdev);
if (cookie == BLK_QC_T_NONE || !(q->limits.features & BLK_FEAT_POLL))
return 0;
blk_flush_plug(current->plug, false);
/*
* We need to be able to enter a frozen queue, similar to how
* timeouts also need to do that. If that is blocked, then we can
* have pending IO when a queue freeze is started, and then the
* wait for the freeze to finish will wait for polled requests to
* timeout as the poller is preventer from entering the queue and
* completing them. As long as we prevent new IO from being queued,
* that should be all that matters.
*/
if (!percpu_ref_tryget(&q->q_usage_counter))
return 0;
if (queue_is_mq(q)) {
ret = blk_mq_poll(q, cookie, iob, flags);
} else {
struct gendisk *disk = q->disk;
if (disk && disk->fops->poll_bio)
ret = disk->fops->poll_bio(bio, 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)
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)) &&
likely(try_cmpxchg(&part->bd_stamp, &stamp, now)) &&
(end || part_in_flight(part)))
__part_stat_add(part, io_ticks, now - stamp);
if (bdev_is_partition(part)) {
part = bdev_whole(part);
goto again;
}
}
unsigned long bdev_start_io_acct(struct block_device *bdev, enum req_op op,
unsigned long start_time)
{
part_stat_lock();
update_io_ticks(bdev, start_time, false);
part_stat_local_inc(bdev, in_flight[op_is_write(op)]);
part_stat_unlock();
return start_time;
}
EXPORT_SYMBOL(bdev_start_io_acct);
/**
* 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 bdev_start_io_acct(bio->bi_bdev, bio_op(bio), jiffies);
}
EXPORT_SYMBOL_GPL(bio_start_io_acct);
void bdev_end_io_acct(struct block_device *bdev, enum req_op op,
unsigned int sectors, 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(bdev, now, true);
part_stat_inc(bdev, ios[sgrp]);
part_stat_add(bdev, sectors[sgrp], sectors);
part_stat_add(bdev, nsecs[sgrp], jiffies_to_nsecs(duration));
part_stat_local_dec(bdev, in_flight[op_is_write(op)]);
part_stat_unlock();
}
EXPORT_SYMBOL(bdev_end_io_acct);
void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
struct block_device *orig_bdev)
{
bdev_end_io_acct(orig_bdev, bio_op(bio), bio_sectors(bio), start_time);
}
EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped);
/**
* 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->cur_ktime = 0;
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;
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);
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);
plug->cur_ktime = 0;
current->flags &= ~PF_BLOCK_TS;
}
/**
* 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((__force u32)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));
/* 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(request_queue, SLAB_PANIC);
blk_debugfs_root = debugfs_create_dir("block", NULL);
return 0;
}
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