forked from Minki/linux
454be724f6
Now we track legacy requests with .q_usage_counter in commit 055f6e18e0
("block: Make q_usage_counter also track legacy requests"), but that
commit never runs and drains legacy queue before waiting for this counter
becoming zero, then IO hang is caused in the test of pulling disk during IO.
This patch fixes the issue by draining requests before waiting for
q_usage_counter becoming zero, both Mauricio and chenxiang reported this
issue, and observed that it can be fixed by this patch.
Link: https://marc.info/?l=linux-block&m=151192424731797&w=2
Fixes: 055f6e18e08f("block: Make q_usage_counter also track legacy requests")
Cc: Wen Xiong <wenxiong@us.ibm.com>
Tested-by: "chenxiang (M)" <chenxiang66@hisilicon.com>
Tested-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2984 lines
72 KiB
C
2984 lines
72 KiB
C
/*
|
|
* Block multiqueue core code
|
|
*
|
|
* Copyright (C) 2013-2014 Jens Axboe
|
|
* Copyright (C) 2013-2014 Christoph Hellwig
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/kmemleak.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/init.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/workqueue.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/llist.h>
|
|
#include <linux/list_sort.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/cache.h>
|
|
#include <linux/sched/sysctl.h>
|
|
#include <linux/sched/topology.h>
|
|
#include <linux/sched/signal.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/crash_dump.h>
|
|
#include <linux/prefetch.h>
|
|
|
|
#include <trace/events/block.h>
|
|
|
|
#include <linux/blk-mq.h>
|
|
#include "blk.h"
|
|
#include "blk-mq.h"
|
|
#include "blk-mq-debugfs.h"
|
|
#include "blk-mq-tag.h"
|
|
#include "blk-stat.h"
|
|
#include "blk-wbt.h"
|
|
#include "blk-mq-sched.h"
|
|
|
|
static bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie);
|
|
static void blk_mq_poll_stats_start(struct request_queue *q);
|
|
static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb);
|
|
|
|
static int blk_mq_poll_stats_bkt(const struct request *rq)
|
|
{
|
|
int ddir, bytes, bucket;
|
|
|
|
ddir = rq_data_dir(rq);
|
|
bytes = blk_rq_bytes(rq);
|
|
|
|
bucket = ddir + 2*(ilog2(bytes) - 9);
|
|
|
|
if (bucket < 0)
|
|
return -1;
|
|
else if (bucket >= BLK_MQ_POLL_STATS_BKTS)
|
|
return ddir + BLK_MQ_POLL_STATS_BKTS - 2;
|
|
|
|
return bucket;
|
|
}
|
|
|
|
/*
|
|
* Check if any of the ctx's have pending work in this hardware queue
|
|
*/
|
|
static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
return !list_empty_careful(&hctx->dispatch) ||
|
|
sbitmap_any_bit_set(&hctx->ctx_map) ||
|
|
blk_mq_sched_has_work(hctx);
|
|
}
|
|
|
|
/*
|
|
* Mark this ctx as having pending work in this hardware queue
|
|
*/
|
|
static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
|
|
struct blk_mq_ctx *ctx)
|
|
{
|
|
if (!sbitmap_test_bit(&hctx->ctx_map, ctx->index_hw))
|
|
sbitmap_set_bit(&hctx->ctx_map, ctx->index_hw);
|
|
}
|
|
|
|
static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
|
|
struct blk_mq_ctx *ctx)
|
|
{
|
|
sbitmap_clear_bit(&hctx->ctx_map, ctx->index_hw);
|
|
}
|
|
|
|
struct mq_inflight {
|
|
struct hd_struct *part;
|
|
unsigned int *inflight;
|
|
};
|
|
|
|
static void blk_mq_check_inflight(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq, void *priv,
|
|
bool reserved)
|
|
{
|
|
struct mq_inflight *mi = priv;
|
|
|
|
if (test_bit(REQ_ATOM_STARTED, &rq->atomic_flags) &&
|
|
!test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags)) {
|
|
/*
|
|
* index[0] counts the specific partition that was asked
|
|
* for. index[1] counts the ones that are active on the
|
|
* whole device, so increment that if mi->part is indeed
|
|
* a partition, and not a whole device.
|
|
*/
|
|
if (rq->part == mi->part)
|
|
mi->inflight[0]++;
|
|
if (mi->part->partno)
|
|
mi->inflight[1]++;
|
|
}
|
|
}
|
|
|
|
void blk_mq_in_flight(struct request_queue *q, struct hd_struct *part,
|
|
unsigned int inflight[2])
|
|
{
|
|
struct mq_inflight mi = { .part = part, .inflight = inflight, };
|
|
|
|
inflight[0] = inflight[1] = 0;
|
|
blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
|
|
}
|
|
|
|
void blk_freeze_queue_start(struct request_queue *q)
|
|
{
|
|
int freeze_depth;
|
|
|
|
freeze_depth = atomic_inc_return(&q->mq_freeze_depth);
|
|
if (freeze_depth == 1) {
|
|
percpu_ref_kill(&q->q_usage_counter);
|
|
if (q->mq_ops)
|
|
blk_mq_run_hw_queues(q, false);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_freeze_queue_start);
|
|
|
|
void blk_mq_freeze_queue_wait(struct request_queue *q)
|
|
{
|
|
wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter));
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait);
|
|
|
|
int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
|
|
unsigned long timeout)
|
|
{
|
|
return wait_event_timeout(q->mq_freeze_wq,
|
|
percpu_ref_is_zero(&q->q_usage_counter),
|
|
timeout);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);
|
|
|
|
/*
|
|
* Guarantee no request is in use, so we can change any data structure of
|
|
* the queue afterward.
|
|
*/
|
|
void blk_freeze_queue(struct request_queue *q)
|
|
{
|
|
/*
|
|
* In the !blk_mq case we are only calling this to kill the
|
|
* q_usage_counter, otherwise this increases the freeze depth
|
|
* and waits for it to return to zero. For this reason there is
|
|
* no blk_unfreeze_queue(), and blk_freeze_queue() is not
|
|
* exported to drivers as the only user for unfreeze is blk_mq.
|
|
*/
|
|
blk_freeze_queue_start(q);
|
|
if (!q->mq_ops)
|
|
blk_drain_queue(q);
|
|
blk_mq_freeze_queue_wait(q);
|
|
}
|
|
|
|
void blk_mq_freeze_queue(struct request_queue *q)
|
|
{
|
|
/*
|
|
* ...just an alias to keep freeze and unfreeze actions balanced
|
|
* in the blk_mq_* namespace
|
|
*/
|
|
blk_freeze_queue(q);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_freeze_queue);
|
|
|
|
void blk_mq_unfreeze_queue(struct request_queue *q)
|
|
{
|
|
int freeze_depth;
|
|
|
|
freeze_depth = atomic_dec_return(&q->mq_freeze_depth);
|
|
WARN_ON_ONCE(freeze_depth < 0);
|
|
if (!freeze_depth) {
|
|
percpu_ref_reinit(&q->q_usage_counter);
|
|
wake_up_all(&q->mq_freeze_wq);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
|
|
|
|
/*
|
|
* FIXME: replace the scsi_internal_device_*block_nowait() calls in the
|
|
* mpt3sas driver such that this function can be removed.
|
|
*/
|
|
void blk_mq_quiesce_queue_nowait(struct request_queue *q)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(q->queue_lock, flags);
|
|
queue_flag_set(QUEUE_FLAG_QUIESCED, q);
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait);
|
|
|
|
/**
|
|
* blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
|
|
* @q: request queue.
|
|
*
|
|
* Note: this function does not prevent that the struct request end_io()
|
|
* callback function is invoked. Once this function is returned, we make
|
|
* sure no dispatch can happen until the queue is unquiesced via
|
|
* blk_mq_unquiesce_queue().
|
|
*/
|
|
void blk_mq_quiesce_queue(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
unsigned int i;
|
|
bool rcu = false;
|
|
|
|
blk_mq_quiesce_queue_nowait(q);
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (hctx->flags & BLK_MQ_F_BLOCKING)
|
|
synchronize_srcu(hctx->queue_rq_srcu);
|
|
else
|
|
rcu = true;
|
|
}
|
|
if (rcu)
|
|
synchronize_rcu();
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
|
|
|
|
/*
|
|
* blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
|
|
* @q: request queue.
|
|
*
|
|
* This function recovers queue into the state before quiescing
|
|
* which is done by blk_mq_quiesce_queue.
|
|
*/
|
|
void blk_mq_unquiesce_queue(struct request_queue *q)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(q->queue_lock, flags);
|
|
queue_flag_clear(QUEUE_FLAG_QUIESCED, q);
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
|
|
/* dispatch requests which are inserted during quiescing */
|
|
blk_mq_run_hw_queues(q, true);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
|
|
|
|
void blk_mq_wake_waiters(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
unsigned int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
if (blk_mq_hw_queue_mapped(hctx))
|
|
blk_mq_tag_wakeup_all(hctx->tags, true);
|
|
}
|
|
|
|
bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
return blk_mq_has_free_tags(hctx->tags);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_can_queue);
|
|
|
|
static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
|
|
unsigned int tag, unsigned int op)
|
|
{
|
|
struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
|
|
struct request *rq = tags->static_rqs[tag];
|
|
|
|
rq->rq_flags = 0;
|
|
|
|
if (data->flags & BLK_MQ_REQ_INTERNAL) {
|
|
rq->tag = -1;
|
|
rq->internal_tag = tag;
|
|
} else {
|
|
if (blk_mq_tag_busy(data->hctx)) {
|
|
rq->rq_flags = RQF_MQ_INFLIGHT;
|
|
atomic_inc(&data->hctx->nr_active);
|
|
}
|
|
rq->tag = tag;
|
|
rq->internal_tag = -1;
|
|
data->hctx->tags->rqs[rq->tag] = rq;
|
|
}
|
|
|
|
INIT_LIST_HEAD(&rq->queuelist);
|
|
/* csd/requeue_work/fifo_time is initialized before use */
|
|
rq->q = data->q;
|
|
rq->mq_ctx = data->ctx;
|
|
rq->cmd_flags = op;
|
|
if (data->flags & BLK_MQ_REQ_PREEMPT)
|
|
rq->rq_flags |= RQF_PREEMPT;
|
|
if (blk_queue_io_stat(data->q))
|
|
rq->rq_flags |= RQF_IO_STAT;
|
|
/* do not touch atomic flags, it needs atomic ops against the timer */
|
|
rq->cpu = -1;
|
|
INIT_HLIST_NODE(&rq->hash);
|
|
RB_CLEAR_NODE(&rq->rb_node);
|
|
rq->rq_disk = NULL;
|
|
rq->part = NULL;
|
|
rq->start_time = jiffies;
|
|
#ifdef CONFIG_BLK_CGROUP
|
|
rq->rl = NULL;
|
|
set_start_time_ns(rq);
|
|
rq->io_start_time_ns = 0;
|
|
#endif
|
|
rq->nr_phys_segments = 0;
|
|
#if defined(CONFIG_BLK_DEV_INTEGRITY)
|
|
rq->nr_integrity_segments = 0;
|
|
#endif
|
|
rq->special = NULL;
|
|
/* tag was already set */
|
|
rq->extra_len = 0;
|
|
|
|
INIT_LIST_HEAD(&rq->timeout_list);
|
|
rq->timeout = 0;
|
|
|
|
rq->end_io = NULL;
|
|
rq->end_io_data = NULL;
|
|
rq->next_rq = NULL;
|
|
|
|
data->ctx->rq_dispatched[op_is_sync(op)]++;
|
|
return rq;
|
|
}
|
|
|
|
static struct request *blk_mq_get_request(struct request_queue *q,
|
|
struct bio *bio, unsigned int op,
|
|
struct blk_mq_alloc_data *data)
|
|
{
|
|
struct elevator_queue *e = q->elevator;
|
|
struct request *rq;
|
|
unsigned int tag;
|
|
bool put_ctx_on_error = false;
|
|
|
|
blk_queue_enter_live(q);
|
|
data->q = q;
|
|
if (likely(!data->ctx)) {
|
|
data->ctx = blk_mq_get_ctx(q);
|
|
put_ctx_on_error = true;
|
|
}
|
|
if (likely(!data->hctx))
|
|
data->hctx = blk_mq_map_queue(q, data->ctx->cpu);
|
|
if (op & REQ_NOWAIT)
|
|
data->flags |= BLK_MQ_REQ_NOWAIT;
|
|
|
|
if (e) {
|
|
data->flags |= BLK_MQ_REQ_INTERNAL;
|
|
|
|
/*
|
|
* Flush requests are special and go directly to the
|
|
* dispatch list.
|
|
*/
|
|
if (!op_is_flush(op) && e->type->ops.mq.limit_depth)
|
|
e->type->ops.mq.limit_depth(op, data);
|
|
}
|
|
|
|
tag = blk_mq_get_tag(data);
|
|
if (tag == BLK_MQ_TAG_FAIL) {
|
|
if (put_ctx_on_error) {
|
|
blk_mq_put_ctx(data->ctx);
|
|
data->ctx = NULL;
|
|
}
|
|
blk_queue_exit(q);
|
|
return NULL;
|
|
}
|
|
|
|
rq = blk_mq_rq_ctx_init(data, tag, op);
|
|
if (!op_is_flush(op)) {
|
|
rq->elv.icq = NULL;
|
|
if (e && e->type->ops.mq.prepare_request) {
|
|
if (e->type->icq_cache && rq_ioc(bio))
|
|
blk_mq_sched_assign_ioc(rq, bio);
|
|
|
|
e->type->ops.mq.prepare_request(rq, bio);
|
|
rq->rq_flags |= RQF_ELVPRIV;
|
|
}
|
|
}
|
|
data->hctx->queued++;
|
|
return rq;
|
|
}
|
|
|
|
struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,
|
|
blk_mq_req_flags_t flags)
|
|
{
|
|
struct blk_mq_alloc_data alloc_data = { .flags = flags };
|
|
struct request *rq;
|
|
int ret;
|
|
|
|
ret = blk_queue_enter(q, flags);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
rq = blk_mq_get_request(q, NULL, op, &alloc_data);
|
|
blk_queue_exit(q);
|
|
|
|
if (!rq)
|
|
return ERR_PTR(-EWOULDBLOCK);
|
|
|
|
blk_mq_put_ctx(alloc_data.ctx);
|
|
|
|
rq->__data_len = 0;
|
|
rq->__sector = (sector_t) -1;
|
|
rq->bio = rq->biotail = NULL;
|
|
return rq;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_alloc_request);
|
|
|
|
struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
|
|
unsigned int op, blk_mq_req_flags_t flags, unsigned int hctx_idx)
|
|
{
|
|
struct blk_mq_alloc_data alloc_data = { .flags = flags };
|
|
struct request *rq;
|
|
unsigned int cpu;
|
|
int ret;
|
|
|
|
/*
|
|
* If the tag allocator sleeps we could get an allocation for a
|
|
* different hardware context. No need to complicate the low level
|
|
* allocator for this for the rare use case of a command tied to
|
|
* a specific queue.
|
|
*/
|
|
if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT)))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
if (hctx_idx >= q->nr_hw_queues)
|
|
return ERR_PTR(-EIO);
|
|
|
|
ret = blk_queue_enter(q, flags);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
/*
|
|
* Check if the hardware context is actually mapped to anything.
|
|
* If not tell the caller that it should skip this queue.
|
|
*/
|
|
alloc_data.hctx = q->queue_hw_ctx[hctx_idx];
|
|
if (!blk_mq_hw_queue_mapped(alloc_data.hctx)) {
|
|
blk_queue_exit(q);
|
|
return ERR_PTR(-EXDEV);
|
|
}
|
|
cpu = cpumask_first(alloc_data.hctx->cpumask);
|
|
alloc_data.ctx = __blk_mq_get_ctx(q, cpu);
|
|
|
|
rq = blk_mq_get_request(q, NULL, op, &alloc_data);
|
|
blk_queue_exit(q);
|
|
|
|
if (!rq)
|
|
return ERR_PTR(-EWOULDBLOCK);
|
|
|
|
return rq;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
|
|
|
|
void blk_mq_free_request(struct request *rq)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
struct elevator_queue *e = q->elevator;
|
|
struct blk_mq_ctx *ctx = rq->mq_ctx;
|
|
struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
|
|
const int sched_tag = rq->internal_tag;
|
|
|
|
if (rq->rq_flags & RQF_ELVPRIV) {
|
|
if (e && e->type->ops.mq.finish_request)
|
|
e->type->ops.mq.finish_request(rq);
|
|
if (rq->elv.icq) {
|
|
put_io_context(rq->elv.icq->ioc);
|
|
rq->elv.icq = NULL;
|
|
}
|
|
}
|
|
|
|
ctx->rq_completed[rq_is_sync(rq)]++;
|
|
if (rq->rq_flags & RQF_MQ_INFLIGHT)
|
|
atomic_dec(&hctx->nr_active);
|
|
|
|
if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
|
|
laptop_io_completion(q->backing_dev_info);
|
|
|
|
wbt_done(q->rq_wb, &rq->issue_stat);
|
|
|
|
if (blk_rq_rl(rq))
|
|
blk_put_rl(blk_rq_rl(rq));
|
|
|
|
clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
|
|
clear_bit(REQ_ATOM_POLL_SLEPT, &rq->atomic_flags);
|
|
if (rq->tag != -1)
|
|
blk_mq_put_tag(hctx, hctx->tags, ctx, rq->tag);
|
|
if (sched_tag != -1)
|
|
blk_mq_put_tag(hctx, hctx->sched_tags, ctx, sched_tag);
|
|
blk_mq_sched_restart(hctx);
|
|
blk_queue_exit(q);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_free_request);
|
|
|
|
inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
|
|
{
|
|
blk_account_io_done(rq);
|
|
|
|
if (rq->end_io) {
|
|
wbt_done(rq->q->rq_wb, &rq->issue_stat);
|
|
rq->end_io(rq, error);
|
|
} else {
|
|
if (unlikely(blk_bidi_rq(rq)))
|
|
blk_mq_free_request(rq->next_rq);
|
|
blk_mq_free_request(rq);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(__blk_mq_end_request);
|
|
|
|
void blk_mq_end_request(struct request *rq, blk_status_t error)
|
|
{
|
|
if (blk_update_request(rq, error, blk_rq_bytes(rq)))
|
|
BUG();
|
|
__blk_mq_end_request(rq, error);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_end_request);
|
|
|
|
static void __blk_mq_complete_request_remote(void *data)
|
|
{
|
|
struct request *rq = data;
|
|
|
|
rq->q->softirq_done_fn(rq);
|
|
}
|
|
|
|
static void __blk_mq_complete_request(struct request *rq)
|
|
{
|
|
struct blk_mq_ctx *ctx = rq->mq_ctx;
|
|
bool shared = false;
|
|
int cpu;
|
|
|
|
if (rq->internal_tag != -1)
|
|
blk_mq_sched_completed_request(rq);
|
|
if (rq->rq_flags & RQF_STATS) {
|
|
blk_mq_poll_stats_start(rq->q);
|
|
blk_stat_add(rq);
|
|
}
|
|
|
|
if (!test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) {
|
|
rq->q->softirq_done_fn(rq);
|
|
return;
|
|
}
|
|
|
|
cpu = get_cpu();
|
|
if (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags))
|
|
shared = cpus_share_cache(cpu, ctx->cpu);
|
|
|
|
if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) {
|
|
rq->csd.func = __blk_mq_complete_request_remote;
|
|
rq->csd.info = rq;
|
|
rq->csd.flags = 0;
|
|
smp_call_function_single_async(ctx->cpu, &rq->csd);
|
|
} else {
|
|
rq->q->softirq_done_fn(rq);
|
|
}
|
|
put_cpu();
|
|
}
|
|
|
|
/**
|
|
* blk_mq_complete_request - end I/O on a request
|
|
* @rq: the request being processed
|
|
*
|
|
* Description:
|
|
* Ends all I/O on a request. It does not handle partial completions.
|
|
* The actual completion happens out-of-order, through a IPI handler.
|
|
**/
|
|
void blk_mq_complete_request(struct request *rq)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
|
|
if (unlikely(blk_should_fake_timeout(q)))
|
|
return;
|
|
if (!blk_mark_rq_complete(rq))
|
|
__blk_mq_complete_request(rq);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_complete_request);
|
|
|
|
int blk_mq_request_started(struct request *rq)
|
|
{
|
|
return test_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_request_started);
|
|
|
|
void blk_mq_start_request(struct request *rq)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
|
|
blk_mq_sched_started_request(rq);
|
|
|
|
trace_block_rq_issue(q, rq);
|
|
|
|
if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) {
|
|
blk_stat_set_issue(&rq->issue_stat, blk_rq_sectors(rq));
|
|
rq->rq_flags |= RQF_STATS;
|
|
wbt_issue(q->rq_wb, &rq->issue_stat);
|
|
}
|
|
|
|
blk_add_timer(rq);
|
|
|
|
WARN_ON_ONCE(test_bit(REQ_ATOM_STARTED, &rq->atomic_flags));
|
|
|
|
/*
|
|
* Mark us as started and clear complete. Complete might have been
|
|
* set if requeue raced with timeout, which then marked it as
|
|
* complete. So be sure to clear complete again when we start
|
|
* the request, otherwise we'll ignore the completion event.
|
|
*
|
|
* Ensure that ->deadline is visible before we set STARTED, such that
|
|
* blk_mq_check_expired() is guaranteed to observe our ->deadline when
|
|
* it observes STARTED.
|
|
*/
|
|
smp_wmb();
|
|
set_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
|
|
if (test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags)) {
|
|
/*
|
|
* Coherence order guarantees these consecutive stores to a
|
|
* single variable propagate in the specified order. Thus the
|
|
* clear_bit() is ordered _after_ the set bit. See
|
|
* blk_mq_check_expired().
|
|
*
|
|
* (the bits must be part of the same byte for this to be
|
|
* true).
|
|
*/
|
|
clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
|
|
}
|
|
|
|
if (q->dma_drain_size && blk_rq_bytes(rq)) {
|
|
/*
|
|
* Make sure space for the drain appears. We know we can do
|
|
* this because max_hw_segments has been adjusted to be one
|
|
* fewer than the device can handle.
|
|
*/
|
|
rq->nr_phys_segments++;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_start_request);
|
|
|
|
/*
|
|
* When we reach here because queue is busy, REQ_ATOM_COMPLETE
|
|
* flag isn't set yet, so there may be race with timeout handler,
|
|
* but given rq->deadline is just set in .queue_rq() under
|
|
* this situation, the race won't be possible in reality because
|
|
* rq->timeout should be set as big enough to cover the window
|
|
* between blk_mq_start_request() called from .queue_rq() and
|
|
* clearing REQ_ATOM_STARTED here.
|
|
*/
|
|
static void __blk_mq_requeue_request(struct request *rq)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
|
|
blk_mq_put_driver_tag(rq);
|
|
|
|
trace_block_rq_requeue(q, rq);
|
|
wbt_requeue(q->rq_wb, &rq->issue_stat);
|
|
blk_mq_sched_requeue_request(rq);
|
|
|
|
if (test_and_clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) {
|
|
if (q->dma_drain_size && blk_rq_bytes(rq))
|
|
rq->nr_phys_segments--;
|
|
}
|
|
}
|
|
|
|
void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
|
|
{
|
|
__blk_mq_requeue_request(rq);
|
|
|
|
BUG_ON(blk_queued_rq(rq));
|
|
blk_mq_add_to_requeue_list(rq, true, kick_requeue_list);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_requeue_request);
|
|
|
|
static void blk_mq_requeue_work(struct work_struct *work)
|
|
{
|
|
struct request_queue *q =
|
|
container_of(work, struct request_queue, requeue_work.work);
|
|
LIST_HEAD(rq_list);
|
|
struct request *rq, *next;
|
|
|
|
spin_lock_irq(&q->requeue_lock);
|
|
list_splice_init(&q->requeue_list, &rq_list);
|
|
spin_unlock_irq(&q->requeue_lock);
|
|
|
|
list_for_each_entry_safe(rq, next, &rq_list, queuelist) {
|
|
if (!(rq->rq_flags & RQF_SOFTBARRIER))
|
|
continue;
|
|
|
|
rq->rq_flags &= ~RQF_SOFTBARRIER;
|
|
list_del_init(&rq->queuelist);
|
|
blk_mq_sched_insert_request(rq, true, false, false, true);
|
|
}
|
|
|
|
while (!list_empty(&rq_list)) {
|
|
rq = list_entry(rq_list.next, struct request, queuelist);
|
|
list_del_init(&rq->queuelist);
|
|
blk_mq_sched_insert_request(rq, false, false, false, true);
|
|
}
|
|
|
|
blk_mq_run_hw_queues(q, false);
|
|
}
|
|
|
|
void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
|
|
bool kick_requeue_list)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* We abuse this flag that is otherwise used by the I/O scheduler to
|
|
* request head insertion from the workqueue.
|
|
*/
|
|
BUG_ON(rq->rq_flags & RQF_SOFTBARRIER);
|
|
|
|
spin_lock_irqsave(&q->requeue_lock, flags);
|
|
if (at_head) {
|
|
rq->rq_flags |= RQF_SOFTBARRIER;
|
|
list_add(&rq->queuelist, &q->requeue_list);
|
|
} else {
|
|
list_add_tail(&rq->queuelist, &q->requeue_list);
|
|
}
|
|
spin_unlock_irqrestore(&q->requeue_lock, flags);
|
|
|
|
if (kick_requeue_list)
|
|
blk_mq_kick_requeue_list(q);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_add_to_requeue_list);
|
|
|
|
void blk_mq_kick_requeue_list(struct request_queue *q)
|
|
{
|
|
kblockd_schedule_delayed_work(&q->requeue_work, 0);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_kick_requeue_list);
|
|
|
|
void blk_mq_delay_kick_requeue_list(struct request_queue *q,
|
|
unsigned long msecs)
|
|
{
|
|
kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work,
|
|
msecs_to_jiffies(msecs));
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
|
|
|
|
struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag)
|
|
{
|
|
if (tag < tags->nr_tags) {
|
|
prefetch(tags->rqs[tag]);
|
|
return tags->rqs[tag];
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_tag_to_rq);
|
|
|
|
struct blk_mq_timeout_data {
|
|
unsigned long next;
|
|
unsigned int next_set;
|
|
};
|
|
|
|
void blk_mq_rq_timed_out(struct request *req, bool reserved)
|
|
{
|
|
const struct blk_mq_ops *ops = req->q->mq_ops;
|
|
enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER;
|
|
|
|
/*
|
|
* We know that complete is set at this point. If STARTED isn't set
|
|
* anymore, then the request isn't active and the "timeout" should
|
|
* just be ignored. This can happen due to the bitflag ordering.
|
|
* Timeout first checks if STARTED is set, and if it is, assumes
|
|
* the request is active. But if we race with completion, then
|
|
* both flags will get cleared. So check here again, and ignore
|
|
* a timeout event with a request that isn't active.
|
|
*/
|
|
if (!test_bit(REQ_ATOM_STARTED, &req->atomic_flags))
|
|
return;
|
|
|
|
if (ops->timeout)
|
|
ret = ops->timeout(req, reserved);
|
|
|
|
switch (ret) {
|
|
case BLK_EH_HANDLED:
|
|
__blk_mq_complete_request(req);
|
|
break;
|
|
case BLK_EH_RESET_TIMER:
|
|
blk_add_timer(req);
|
|
blk_clear_rq_complete(req);
|
|
break;
|
|
case BLK_EH_NOT_HANDLED:
|
|
break;
|
|
default:
|
|
printk(KERN_ERR "block: bad eh return: %d\n", ret);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq, void *priv, bool reserved)
|
|
{
|
|
struct blk_mq_timeout_data *data = priv;
|
|
unsigned long deadline;
|
|
|
|
if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
|
|
return;
|
|
|
|
/*
|
|
* Ensures that if we see STARTED we must also see our
|
|
* up-to-date deadline, see blk_mq_start_request().
|
|
*/
|
|
smp_rmb();
|
|
|
|
deadline = READ_ONCE(rq->deadline);
|
|
|
|
/*
|
|
* The rq being checked may have been freed and reallocated
|
|
* out already here, we avoid this race by checking rq->deadline
|
|
* and REQ_ATOM_COMPLETE flag together:
|
|
*
|
|
* - if rq->deadline is observed as new value because of
|
|
* reusing, the rq won't be timed out because of timing.
|
|
* - if rq->deadline is observed as previous value,
|
|
* REQ_ATOM_COMPLETE flag won't be cleared in reuse path
|
|
* because we put a barrier between setting rq->deadline
|
|
* and clearing the flag in blk_mq_start_request(), so
|
|
* this rq won't be timed out too.
|
|
*/
|
|
if (time_after_eq(jiffies, deadline)) {
|
|
if (!blk_mark_rq_complete(rq)) {
|
|
/*
|
|
* Again coherence order ensures that consecutive reads
|
|
* from the same variable must be in that order. This
|
|
* ensures that if we see COMPLETE clear, we must then
|
|
* see STARTED set and we'll ignore this timeout.
|
|
*
|
|
* (There's also the MB implied by the test_and_clear())
|
|
*/
|
|
blk_mq_rq_timed_out(rq, reserved);
|
|
}
|
|
} else if (!data->next_set || time_after(data->next, deadline)) {
|
|
data->next = deadline;
|
|
data->next_set = 1;
|
|
}
|
|
}
|
|
|
|
static void blk_mq_timeout_work(struct work_struct *work)
|
|
{
|
|
struct request_queue *q =
|
|
container_of(work, struct request_queue, timeout_work);
|
|
struct blk_mq_timeout_data data = {
|
|
.next = 0,
|
|
.next_set = 0,
|
|
};
|
|
int i;
|
|
|
|
/* A deadlock might occur if a request is stuck requiring a
|
|
* timeout at the same time a queue freeze is waiting
|
|
* completion, since the timeout code would not be able to
|
|
* acquire the queue reference here.
|
|
*
|
|
* That's why we don't use blk_queue_enter here; instead, we use
|
|
* percpu_ref_tryget directly, because we need to be able to
|
|
* obtain a reference even in the short window between the queue
|
|
* starting to freeze, by dropping the first reference in
|
|
* blk_freeze_queue_start, and the moment the last request is
|
|
* consumed, marked by the instant q_usage_counter reaches
|
|
* zero.
|
|
*/
|
|
if (!percpu_ref_tryget(&q->q_usage_counter))
|
|
return;
|
|
|
|
blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &data);
|
|
|
|
if (data.next_set) {
|
|
data.next = blk_rq_timeout(round_jiffies_up(data.next));
|
|
mod_timer(&q->timeout, data.next);
|
|
} else {
|
|
struct blk_mq_hw_ctx *hctx;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
/* the hctx may be unmapped, so check it here */
|
|
if (blk_mq_hw_queue_mapped(hctx))
|
|
blk_mq_tag_idle(hctx);
|
|
}
|
|
}
|
|
blk_queue_exit(q);
|
|
}
|
|
|
|
struct flush_busy_ctx_data {
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct list_head *list;
|
|
};
|
|
|
|
static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
|
|
{
|
|
struct flush_busy_ctx_data *flush_data = data;
|
|
struct blk_mq_hw_ctx *hctx = flush_data->hctx;
|
|
struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
|
|
|
|
sbitmap_clear_bit(sb, bitnr);
|
|
spin_lock(&ctx->lock);
|
|
list_splice_tail_init(&ctx->rq_list, flush_data->list);
|
|
spin_unlock(&ctx->lock);
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Process software queues that have been marked busy, splicing them
|
|
* to the for-dispatch
|
|
*/
|
|
void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
|
|
{
|
|
struct flush_busy_ctx_data data = {
|
|
.hctx = hctx,
|
|
.list = list,
|
|
};
|
|
|
|
sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs);
|
|
|
|
struct dispatch_rq_data {
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct request *rq;
|
|
};
|
|
|
|
static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr,
|
|
void *data)
|
|
{
|
|
struct dispatch_rq_data *dispatch_data = data;
|
|
struct blk_mq_hw_ctx *hctx = dispatch_data->hctx;
|
|
struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
|
|
|
|
spin_lock(&ctx->lock);
|
|
if (unlikely(!list_empty(&ctx->rq_list))) {
|
|
dispatch_data->rq = list_entry_rq(ctx->rq_list.next);
|
|
list_del_init(&dispatch_data->rq->queuelist);
|
|
if (list_empty(&ctx->rq_list))
|
|
sbitmap_clear_bit(sb, bitnr);
|
|
}
|
|
spin_unlock(&ctx->lock);
|
|
|
|
return !dispatch_data->rq;
|
|
}
|
|
|
|
struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
|
|
struct blk_mq_ctx *start)
|
|
{
|
|
unsigned off = start ? start->index_hw : 0;
|
|
struct dispatch_rq_data data = {
|
|
.hctx = hctx,
|
|
.rq = NULL,
|
|
};
|
|
|
|
__sbitmap_for_each_set(&hctx->ctx_map, off,
|
|
dispatch_rq_from_ctx, &data);
|
|
|
|
return data.rq;
|
|
}
|
|
|
|
static inline unsigned int queued_to_index(unsigned int queued)
|
|
{
|
|
if (!queued)
|
|
return 0;
|
|
|
|
return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1);
|
|
}
|
|
|
|
bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx,
|
|
bool wait)
|
|
{
|
|
struct blk_mq_alloc_data data = {
|
|
.q = rq->q,
|
|
.hctx = blk_mq_map_queue(rq->q, rq->mq_ctx->cpu),
|
|
.flags = wait ? 0 : BLK_MQ_REQ_NOWAIT,
|
|
};
|
|
|
|
might_sleep_if(wait);
|
|
|
|
if (rq->tag != -1)
|
|
goto done;
|
|
|
|
if (blk_mq_tag_is_reserved(data.hctx->sched_tags, rq->internal_tag))
|
|
data.flags |= BLK_MQ_REQ_RESERVED;
|
|
|
|
rq->tag = blk_mq_get_tag(&data);
|
|
if (rq->tag >= 0) {
|
|
if (blk_mq_tag_busy(data.hctx)) {
|
|
rq->rq_flags |= RQF_MQ_INFLIGHT;
|
|
atomic_inc(&data.hctx->nr_active);
|
|
}
|
|
data.hctx->tags->rqs[rq->tag] = rq;
|
|
}
|
|
|
|
done:
|
|
if (hctx)
|
|
*hctx = data.hctx;
|
|
return rq->tag != -1;
|
|
}
|
|
|
|
static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
|
|
int flags, void *key)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
|
|
hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait);
|
|
|
|
list_del_init(&wait->entry);
|
|
blk_mq_run_hw_queue(hctx, true);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Mark us waiting for a tag. For shared tags, this involves hooking us into
|
|
* the tag wakeups. For non-shared tags, we can simply mark us nedeing a
|
|
* restart. For both caes, take care to check the condition again after
|
|
* marking us as waiting.
|
|
*/
|
|
static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx **hctx,
|
|
struct request *rq)
|
|
{
|
|
struct blk_mq_hw_ctx *this_hctx = *hctx;
|
|
bool shared_tags = (this_hctx->flags & BLK_MQ_F_TAG_SHARED) != 0;
|
|
struct sbq_wait_state *ws;
|
|
wait_queue_entry_t *wait;
|
|
bool ret;
|
|
|
|
if (!shared_tags) {
|
|
if (!test_bit(BLK_MQ_S_SCHED_RESTART, &this_hctx->state))
|
|
set_bit(BLK_MQ_S_SCHED_RESTART, &this_hctx->state);
|
|
} else {
|
|
wait = &this_hctx->dispatch_wait;
|
|
if (!list_empty_careful(&wait->entry))
|
|
return false;
|
|
|
|
spin_lock(&this_hctx->lock);
|
|
if (!list_empty(&wait->entry)) {
|
|
spin_unlock(&this_hctx->lock);
|
|
return false;
|
|
}
|
|
|
|
ws = bt_wait_ptr(&this_hctx->tags->bitmap_tags, this_hctx);
|
|
add_wait_queue(&ws->wait, wait);
|
|
}
|
|
|
|
/*
|
|
* It's possible that a tag was freed in the window between the
|
|
* allocation failure and adding the hardware queue to the wait
|
|
* queue.
|
|
*/
|
|
ret = blk_mq_get_driver_tag(rq, hctx, false);
|
|
|
|
if (!shared_tags) {
|
|
/*
|
|
* Don't clear RESTART here, someone else could have set it.
|
|
* At most this will cost an extra queue run.
|
|
*/
|
|
return ret;
|
|
} else {
|
|
if (!ret) {
|
|
spin_unlock(&this_hctx->lock);
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* We got a tag, remove ourselves from the wait queue to ensure
|
|
* someone else gets the wakeup.
|
|
*/
|
|
spin_lock_irq(&ws->wait.lock);
|
|
list_del_init(&wait->entry);
|
|
spin_unlock_irq(&ws->wait.lock);
|
|
spin_unlock(&this_hctx->lock);
|
|
return true;
|
|
}
|
|
}
|
|
|
|
bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
|
|
bool got_budget)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct request *rq, *nxt;
|
|
bool no_tag = false;
|
|
int errors, queued;
|
|
|
|
if (list_empty(list))
|
|
return false;
|
|
|
|
WARN_ON(!list_is_singular(list) && got_budget);
|
|
|
|
/*
|
|
* Now process all the entries, sending them to the driver.
|
|
*/
|
|
errors = queued = 0;
|
|
do {
|
|
struct blk_mq_queue_data bd;
|
|
blk_status_t ret;
|
|
|
|
rq = list_first_entry(list, struct request, queuelist);
|
|
if (!blk_mq_get_driver_tag(rq, &hctx, false)) {
|
|
/*
|
|
* The initial allocation attempt failed, so we need to
|
|
* rerun the hardware queue when a tag is freed. The
|
|
* waitqueue takes care of that. If the queue is run
|
|
* before we add this entry back on the dispatch list,
|
|
* we'll re-run it below.
|
|
*/
|
|
if (!blk_mq_mark_tag_wait(&hctx, rq)) {
|
|
if (got_budget)
|
|
blk_mq_put_dispatch_budget(hctx);
|
|
/*
|
|
* For non-shared tags, the RESTART check
|
|
* will suffice.
|
|
*/
|
|
if (hctx->flags & BLK_MQ_F_TAG_SHARED)
|
|
no_tag = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!got_budget && !blk_mq_get_dispatch_budget(hctx)) {
|
|
blk_mq_put_driver_tag(rq);
|
|
break;
|
|
}
|
|
|
|
list_del_init(&rq->queuelist);
|
|
|
|
bd.rq = rq;
|
|
|
|
/*
|
|
* Flag last if we have no more requests, or if we have more
|
|
* but can't assign a driver tag to it.
|
|
*/
|
|
if (list_empty(list))
|
|
bd.last = true;
|
|
else {
|
|
nxt = list_first_entry(list, struct request, queuelist);
|
|
bd.last = !blk_mq_get_driver_tag(nxt, NULL, false);
|
|
}
|
|
|
|
ret = q->mq_ops->queue_rq(hctx, &bd);
|
|
if (ret == BLK_STS_RESOURCE) {
|
|
/*
|
|
* If an I/O scheduler has been configured and we got a
|
|
* driver tag for the next request already, free it
|
|
* again.
|
|
*/
|
|
if (!list_empty(list)) {
|
|
nxt = list_first_entry(list, struct request, queuelist);
|
|
blk_mq_put_driver_tag(nxt);
|
|
}
|
|
list_add(&rq->queuelist, list);
|
|
__blk_mq_requeue_request(rq);
|
|
break;
|
|
}
|
|
|
|
if (unlikely(ret != BLK_STS_OK)) {
|
|
errors++;
|
|
blk_mq_end_request(rq, BLK_STS_IOERR);
|
|
continue;
|
|
}
|
|
|
|
queued++;
|
|
} while (!list_empty(list));
|
|
|
|
hctx->dispatched[queued_to_index(queued)]++;
|
|
|
|
/*
|
|
* Any items that need requeuing? Stuff them into hctx->dispatch,
|
|
* that is where we will continue on next queue run.
|
|
*/
|
|
if (!list_empty(list)) {
|
|
spin_lock(&hctx->lock);
|
|
list_splice_init(list, &hctx->dispatch);
|
|
spin_unlock(&hctx->lock);
|
|
|
|
/*
|
|
* If SCHED_RESTART was set by the caller of this function and
|
|
* it is no longer set that means that it was cleared by another
|
|
* thread and hence that a queue rerun is needed.
|
|
*
|
|
* If 'no_tag' is set, that means that we failed getting
|
|
* a driver tag with an I/O scheduler attached. If our dispatch
|
|
* waitqueue is no longer active, ensure that we run the queue
|
|
* AFTER adding our entries back to the list.
|
|
*
|
|
* If no I/O scheduler has been configured it is possible that
|
|
* the hardware queue got stopped and restarted before requests
|
|
* were pushed back onto the dispatch list. Rerun the queue to
|
|
* avoid starvation. Notes:
|
|
* - blk_mq_run_hw_queue() checks whether or not a queue has
|
|
* been stopped before rerunning a queue.
|
|
* - Some but not all block drivers stop a queue before
|
|
* returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
|
|
* and dm-rq.
|
|
*/
|
|
if (!blk_mq_sched_needs_restart(hctx) ||
|
|
(no_tag && list_empty_careful(&hctx->dispatch_wait.entry)))
|
|
blk_mq_run_hw_queue(hctx, true);
|
|
}
|
|
|
|
return (queued + errors) != 0;
|
|
}
|
|
|
|
static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
int srcu_idx;
|
|
|
|
/*
|
|
* We should be running this queue from one of the CPUs that
|
|
* are mapped to it.
|
|
*/
|
|
WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) &&
|
|
cpu_online(hctx->next_cpu));
|
|
|
|
/*
|
|
* We can't run the queue inline with ints disabled. Ensure that
|
|
* we catch bad users of this early.
|
|
*/
|
|
WARN_ON_ONCE(in_interrupt());
|
|
|
|
if (!(hctx->flags & BLK_MQ_F_BLOCKING)) {
|
|
rcu_read_lock();
|
|
blk_mq_sched_dispatch_requests(hctx);
|
|
rcu_read_unlock();
|
|
} else {
|
|
might_sleep();
|
|
|
|
srcu_idx = srcu_read_lock(hctx->queue_rq_srcu);
|
|
blk_mq_sched_dispatch_requests(hctx);
|
|
srcu_read_unlock(hctx->queue_rq_srcu, srcu_idx);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* It'd be great if the workqueue API had a way to pass
|
|
* in a mask and had some smarts for more clever placement.
|
|
* For now we just round-robin here, switching for every
|
|
* BLK_MQ_CPU_WORK_BATCH queued items.
|
|
*/
|
|
static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
if (hctx->queue->nr_hw_queues == 1)
|
|
return WORK_CPU_UNBOUND;
|
|
|
|
if (--hctx->next_cpu_batch <= 0) {
|
|
int next_cpu;
|
|
|
|
next_cpu = cpumask_next(hctx->next_cpu, hctx->cpumask);
|
|
if (next_cpu >= nr_cpu_ids)
|
|
next_cpu = cpumask_first(hctx->cpumask);
|
|
|
|
hctx->next_cpu = next_cpu;
|
|
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
|
|
}
|
|
|
|
return hctx->next_cpu;
|
|
}
|
|
|
|
static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async,
|
|
unsigned long msecs)
|
|
{
|
|
if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx)))
|
|
return;
|
|
|
|
if (unlikely(blk_mq_hctx_stopped(hctx)))
|
|
return;
|
|
|
|
if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
|
|
int cpu = get_cpu();
|
|
if (cpumask_test_cpu(cpu, hctx->cpumask)) {
|
|
__blk_mq_run_hw_queue(hctx);
|
|
put_cpu();
|
|
return;
|
|
}
|
|
|
|
put_cpu();
|
|
}
|
|
|
|
kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx),
|
|
&hctx->run_work,
|
|
msecs_to_jiffies(msecs));
|
|
}
|
|
|
|
void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
|
|
{
|
|
__blk_mq_delay_run_hw_queue(hctx, true, msecs);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_delay_run_hw_queue);
|
|
|
|
bool blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
|
|
{
|
|
if (blk_mq_hctx_has_pending(hctx)) {
|
|
__blk_mq_delay_run_hw_queue(hctx, async, 0);
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_run_hw_queue);
|
|
|
|
void blk_mq_run_hw_queues(struct request_queue *q, bool async)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (blk_mq_hctx_stopped(hctx))
|
|
continue;
|
|
|
|
blk_mq_run_hw_queue(hctx, async);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_run_hw_queues);
|
|
|
|
/**
|
|
* blk_mq_queue_stopped() - check whether one or more hctxs have been stopped
|
|
* @q: request queue.
|
|
*
|
|
* The caller is responsible for serializing this function against
|
|
* blk_mq_{start,stop}_hw_queue().
|
|
*/
|
|
bool blk_mq_queue_stopped(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
if (blk_mq_hctx_stopped(hctx))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_queue_stopped);
|
|
|
|
/*
|
|
* This function is often used for pausing .queue_rq() by driver when
|
|
* there isn't enough resource or some conditions aren't satisfied, and
|
|
* BLK_STS_RESOURCE is usually returned.
|
|
*
|
|
* We do not guarantee that dispatch can be drained or blocked
|
|
* after blk_mq_stop_hw_queue() returns. Please use
|
|
* blk_mq_quiesce_queue() for that requirement.
|
|
*/
|
|
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
cancel_delayed_work(&hctx->run_work);
|
|
|
|
set_bit(BLK_MQ_S_STOPPED, &hctx->state);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_stop_hw_queue);
|
|
|
|
/*
|
|
* This function is often used for pausing .queue_rq() by driver when
|
|
* there isn't enough resource or some conditions aren't satisfied, and
|
|
* BLK_STS_RESOURCE is usually returned.
|
|
*
|
|
* We do not guarantee that dispatch can be drained or blocked
|
|
* after blk_mq_stop_hw_queues() returns. Please use
|
|
* blk_mq_quiesce_queue() for that requirement.
|
|
*/
|
|
void blk_mq_stop_hw_queues(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
blk_mq_stop_hw_queue(hctx);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_stop_hw_queues);
|
|
|
|
void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
|
|
|
|
blk_mq_run_hw_queue(hctx, false);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_start_hw_queue);
|
|
|
|
void blk_mq_start_hw_queues(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
blk_mq_start_hw_queue(hctx);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_start_hw_queues);
|
|
|
|
void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
|
|
{
|
|
if (!blk_mq_hctx_stopped(hctx))
|
|
return;
|
|
|
|
clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
|
|
blk_mq_run_hw_queue(hctx, async);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue);
|
|
|
|
void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
blk_mq_start_stopped_hw_queue(hctx, async);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
|
|
|
|
static void blk_mq_run_work_fn(struct work_struct *work)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
|
|
hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work);
|
|
|
|
/*
|
|
* If we are stopped, don't run the queue. The exception is if
|
|
* BLK_MQ_S_START_ON_RUN is set. For that case, we auto-clear
|
|
* the STOPPED bit and run it.
|
|
*/
|
|
if (test_bit(BLK_MQ_S_STOPPED, &hctx->state)) {
|
|
if (!test_bit(BLK_MQ_S_START_ON_RUN, &hctx->state))
|
|
return;
|
|
|
|
clear_bit(BLK_MQ_S_START_ON_RUN, &hctx->state);
|
|
clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
|
|
}
|
|
|
|
__blk_mq_run_hw_queue(hctx);
|
|
}
|
|
|
|
|
|
void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
|
|
{
|
|
if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx)))
|
|
return;
|
|
|
|
/*
|
|
* Stop the hw queue, then modify currently delayed work.
|
|
* This should prevent us from running the queue prematurely.
|
|
* Mark the queue as auto-clearing STOPPED when it runs.
|
|
*/
|
|
blk_mq_stop_hw_queue(hctx);
|
|
set_bit(BLK_MQ_S_START_ON_RUN, &hctx->state);
|
|
kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx),
|
|
&hctx->run_work,
|
|
msecs_to_jiffies(msecs));
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_delay_queue);
|
|
|
|
static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq,
|
|
bool at_head)
|
|
{
|
|
struct blk_mq_ctx *ctx = rq->mq_ctx;
|
|
|
|
lockdep_assert_held(&ctx->lock);
|
|
|
|
trace_block_rq_insert(hctx->queue, rq);
|
|
|
|
if (at_head)
|
|
list_add(&rq->queuelist, &ctx->rq_list);
|
|
else
|
|
list_add_tail(&rq->queuelist, &ctx->rq_list);
|
|
}
|
|
|
|
void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
|
|
bool at_head)
|
|
{
|
|
struct blk_mq_ctx *ctx = rq->mq_ctx;
|
|
|
|
lockdep_assert_held(&ctx->lock);
|
|
|
|
__blk_mq_insert_req_list(hctx, rq, at_head);
|
|
blk_mq_hctx_mark_pending(hctx, ctx);
|
|
}
|
|
|
|
/*
|
|
* Should only be used carefully, when the caller knows we want to
|
|
* bypass a potential IO scheduler on the target device.
|
|
*/
|
|
void blk_mq_request_bypass_insert(struct request *rq, bool run_queue)
|
|
{
|
|
struct blk_mq_ctx *ctx = rq->mq_ctx;
|
|
struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(rq->q, ctx->cpu);
|
|
|
|
spin_lock(&hctx->lock);
|
|
list_add_tail(&rq->queuelist, &hctx->dispatch);
|
|
spin_unlock(&hctx->lock);
|
|
|
|
if (run_queue)
|
|
blk_mq_run_hw_queue(hctx, false);
|
|
}
|
|
|
|
void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
|
|
struct list_head *list)
|
|
|
|
{
|
|
/*
|
|
* preemption doesn't flush plug list, so it's possible ctx->cpu is
|
|
* offline now
|
|
*/
|
|
spin_lock(&ctx->lock);
|
|
while (!list_empty(list)) {
|
|
struct request *rq;
|
|
|
|
rq = list_first_entry(list, struct request, queuelist);
|
|
BUG_ON(rq->mq_ctx != ctx);
|
|
list_del_init(&rq->queuelist);
|
|
__blk_mq_insert_req_list(hctx, rq, false);
|
|
}
|
|
blk_mq_hctx_mark_pending(hctx, ctx);
|
|
spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
static int plug_ctx_cmp(void *priv, struct list_head *a, struct list_head *b)
|
|
{
|
|
struct request *rqa = container_of(a, struct request, queuelist);
|
|
struct request *rqb = container_of(b, struct request, queuelist);
|
|
|
|
return !(rqa->mq_ctx < rqb->mq_ctx ||
|
|
(rqa->mq_ctx == rqb->mq_ctx &&
|
|
blk_rq_pos(rqa) < blk_rq_pos(rqb)));
|
|
}
|
|
|
|
void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
|
|
{
|
|
struct blk_mq_ctx *this_ctx;
|
|
struct request_queue *this_q;
|
|
struct request *rq;
|
|
LIST_HEAD(list);
|
|
LIST_HEAD(ctx_list);
|
|
unsigned int depth;
|
|
|
|
list_splice_init(&plug->mq_list, &list);
|
|
|
|
list_sort(NULL, &list, plug_ctx_cmp);
|
|
|
|
this_q = NULL;
|
|
this_ctx = NULL;
|
|
depth = 0;
|
|
|
|
while (!list_empty(&list)) {
|
|
rq = list_entry_rq(list.next);
|
|
list_del_init(&rq->queuelist);
|
|
BUG_ON(!rq->q);
|
|
if (rq->mq_ctx != this_ctx) {
|
|
if (this_ctx) {
|
|
trace_block_unplug(this_q, depth, from_schedule);
|
|
blk_mq_sched_insert_requests(this_q, this_ctx,
|
|
&ctx_list,
|
|
from_schedule);
|
|
}
|
|
|
|
this_ctx = rq->mq_ctx;
|
|
this_q = rq->q;
|
|
depth = 0;
|
|
}
|
|
|
|
depth++;
|
|
list_add_tail(&rq->queuelist, &ctx_list);
|
|
}
|
|
|
|
/*
|
|
* If 'this_ctx' is set, we know we have entries to complete
|
|
* on 'ctx_list'. Do those.
|
|
*/
|
|
if (this_ctx) {
|
|
trace_block_unplug(this_q, depth, from_schedule);
|
|
blk_mq_sched_insert_requests(this_q, this_ctx, &ctx_list,
|
|
from_schedule);
|
|
}
|
|
}
|
|
|
|
static void blk_mq_bio_to_request(struct request *rq, struct bio *bio)
|
|
{
|
|
blk_init_request_from_bio(rq, bio);
|
|
|
|
blk_rq_set_rl(rq, blk_get_rl(rq->q, bio));
|
|
|
|
blk_account_io_start(rq, true);
|
|
}
|
|
|
|
static inline void blk_mq_queue_io(struct blk_mq_hw_ctx *hctx,
|
|
struct blk_mq_ctx *ctx,
|
|
struct request *rq)
|
|
{
|
|
spin_lock(&ctx->lock);
|
|
__blk_mq_insert_request(hctx, rq, false);
|
|
spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
static blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, struct request *rq)
|
|
{
|
|
if (rq->tag != -1)
|
|
return blk_tag_to_qc_t(rq->tag, hctx->queue_num, false);
|
|
|
|
return blk_tag_to_qc_t(rq->internal_tag, hctx->queue_num, true);
|
|
}
|
|
|
|
static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq,
|
|
blk_qc_t *cookie, bool may_sleep)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
struct blk_mq_queue_data bd = {
|
|
.rq = rq,
|
|
.last = true,
|
|
};
|
|
blk_qc_t new_cookie;
|
|
blk_status_t ret;
|
|
bool run_queue = true;
|
|
|
|
/* RCU or SRCU read lock is needed before checking quiesced flag */
|
|
if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) {
|
|
run_queue = false;
|
|
goto insert;
|
|
}
|
|
|
|
if (q->elevator)
|
|
goto insert;
|
|
|
|
if (!blk_mq_get_driver_tag(rq, NULL, false))
|
|
goto insert;
|
|
|
|
if (!blk_mq_get_dispatch_budget(hctx)) {
|
|
blk_mq_put_driver_tag(rq);
|
|
goto insert;
|
|
}
|
|
|
|
new_cookie = request_to_qc_t(hctx, rq);
|
|
|
|
/*
|
|
* For OK queue, we are done. For error, kill it. Any other
|
|
* error (busy), just add it to our list as we previously
|
|
* would have done
|
|
*/
|
|
ret = q->mq_ops->queue_rq(hctx, &bd);
|
|
switch (ret) {
|
|
case BLK_STS_OK:
|
|
*cookie = new_cookie;
|
|
return;
|
|
case BLK_STS_RESOURCE:
|
|
__blk_mq_requeue_request(rq);
|
|
goto insert;
|
|
default:
|
|
*cookie = BLK_QC_T_NONE;
|
|
blk_mq_end_request(rq, ret);
|
|
return;
|
|
}
|
|
|
|
insert:
|
|
blk_mq_sched_insert_request(rq, false, run_queue, false, may_sleep);
|
|
}
|
|
|
|
static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq, blk_qc_t *cookie)
|
|
{
|
|
if (!(hctx->flags & BLK_MQ_F_BLOCKING)) {
|
|
rcu_read_lock();
|
|
__blk_mq_try_issue_directly(hctx, rq, cookie, false);
|
|
rcu_read_unlock();
|
|
} else {
|
|
unsigned int srcu_idx;
|
|
|
|
might_sleep();
|
|
|
|
srcu_idx = srcu_read_lock(hctx->queue_rq_srcu);
|
|
__blk_mq_try_issue_directly(hctx, rq, cookie, true);
|
|
srcu_read_unlock(hctx->queue_rq_srcu, srcu_idx);
|
|
}
|
|
}
|
|
|
|
static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
|
|
{
|
|
const int is_sync = op_is_sync(bio->bi_opf);
|
|
const int is_flush_fua = op_is_flush(bio->bi_opf);
|
|
struct blk_mq_alloc_data data = { .flags = 0 };
|
|
struct request *rq;
|
|
unsigned int request_count = 0;
|
|
struct blk_plug *plug;
|
|
struct request *same_queue_rq = NULL;
|
|
blk_qc_t cookie;
|
|
unsigned int wb_acct;
|
|
|
|
blk_queue_bounce(q, &bio);
|
|
|
|
blk_queue_split(q, &bio);
|
|
|
|
if (!bio_integrity_prep(bio))
|
|
return BLK_QC_T_NONE;
|
|
|
|
if (!is_flush_fua && !blk_queue_nomerges(q) &&
|
|
blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq))
|
|
return BLK_QC_T_NONE;
|
|
|
|
if (blk_mq_sched_bio_merge(q, bio))
|
|
return BLK_QC_T_NONE;
|
|
|
|
wb_acct = wbt_wait(q->rq_wb, bio, NULL);
|
|
|
|
trace_block_getrq(q, bio, bio->bi_opf);
|
|
|
|
rq = blk_mq_get_request(q, bio, bio->bi_opf, &data);
|
|
if (unlikely(!rq)) {
|
|
__wbt_done(q->rq_wb, wb_acct);
|
|
if (bio->bi_opf & REQ_NOWAIT)
|
|
bio_wouldblock_error(bio);
|
|
return BLK_QC_T_NONE;
|
|
}
|
|
|
|
wbt_track(&rq->issue_stat, wb_acct);
|
|
|
|
cookie = request_to_qc_t(data.hctx, rq);
|
|
|
|
plug = current->plug;
|
|
if (unlikely(is_flush_fua)) {
|
|
blk_mq_put_ctx(data.ctx);
|
|
blk_mq_bio_to_request(rq, bio);
|
|
|
|
/* bypass scheduler for flush rq */
|
|
blk_insert_flush(rq);
|
|
blk_mq_run_hw_queue(data.hctx, true);
|
|
} else if (plug && q->nr_hw_queues == 1) {
|
|
struct request *last = NULL;
|
|
|
|
blk_mq_put_ctx(data.ctx);
|
|
blk_mq_bio_to_request(rq, bio);
|
|
|
|
/*
|
|
* @request_count may become stale because of schedule
|
|
* out, so check the list again.
|
|
*/
|
|
if (list_empty(&plug->mq_list))
|
|
request_count = 0;
|
|
else if (blk_queue_nomerges(q))
|
|
request_count = blk_plug_queued_count(q);
|
|
|
|
if (!request_count)
|
|
trace_block_plug(q);
|
|
else
|
|
last = list_entry_rq(plug->mq_list.prev);
|
|
|
|
if (request_count >= BLK_MAX_REQUEST_COUNT || (last &&
|
|
blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
|
|
blk_flush_plug_list(plug, false);
|
|
trace_block_plug(q);
|
|
}
|
|
|
|
list_add_tail(&rq->queuelist, &plug->mq_list);
|
|
} else if (plug && !blk_queue_nomerges(q)) {
|
|
blk_mq_bio_to_request(rq, bio);
|
|
|
|
/*
|
|
* We do limited plugging. If the bio can be merged, do that.
|
|
* Otherwise the existing request in the plug list will be
|
|
* issued. So the plug list will have one request at most
|
|
* The plug list might get flushed before this. If that happens,
|
|
* the plug list is empty, and same_queue_rq is invalid.
|
|
*/
|
|
if (list_empty(&plug->mq_list))
|
|
same_queue_rq = NULL;
|
|
if (same_queue_rq)
|
|
list_del_init(&same_queue_rq->queuelist);
|
|
list_add_tail(&rq->queuelist, &plug->mq_list);
|
|
|
|
blk_mq_put_ctx(data.ctx);
|
|
|
|
if (same_queue_rq) {
|
|
data.hctx = blk_mq_map_queue(q,
|
|
same_queue_rq->mq_ctx->cpu);
|
|
blk_mq_try_issue_directly(data.hctx, same_queue_rq,
|
|
&cookie);
|
|
}
|
|
} else if (q->nr_hw_queues > 1 && is_sync) {
|
|
blk_mq_put_ctx(data.ctx);
|
|
blk_mq_bio_to_request(rq, bio);
|
|
blk_mq_try_issue_directly(data.hctx, rq, &cookie);
|
|
} else if (q->elevator) {
|
|
blk_mq_put_ctx(data.ctx);
|
|
blk_mq_bio_to_request(rq, bio);
|
|
blk_mq_sched_insert_request(rq, false, true, true, true);
|
|
} else {
|
|
blk_mq_put_ctx(data.ctx);
|
|
blk_mq_bio_to_request(rq, bio);
|
|
blk_mq_queue_io(data.hctx, data.ctx, rq);
|
|
blk_mq_run_hw_queue(data.hctx, true);
|
|
}
|
|
|
|
return cookie;
|
|
}
|
|
|
|
void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
|
|
unsigned int hctx_idx)
|
|
{
|
|
struct page *page;
|
|
|
|
if (tags->rqs && set->ops->exit_request) {
|
|
int i;
|
|
|
|
for (i = 0; i < tags->nr_tags; i++) {
|
|
struct request *rq = tags->static_rqs[i];
|
|
|
|
if (!rq)
|
|
continue;
|
|
set->ops->exit_request(set, rq, hctx_idx);
|
|
tags->static_rqs[i] = NULL;
|
|
}
|
|
}
|
|
|
|
while (!list_empty(&tags->page_list)) {
|
|
page = list_first_entry(&tags->page_list, struct page, lru);
|
|
list_del_init(&page->lru);
|
|
/*
|
|
* Remove kmemleak object previously allocated in
|
|
* blk_mq_init_rq_map().
|
|
*/
|
|
kmemleak_free(page_address(page));
|
|
__free_pages(page, page->private);
|
|
}
|
|
}
|
|
|
|
void blk_mq_free_rq_map(struct blk_mq_tags *tags)
|
|
{
|
|
kfree(tags->rqs);
|
|
tags->rqs = NULL;
|
|
kfree(tags->static_rqs);
|
|
tags->static_rqs = NULL;
|
|
|
|
blk_mq_free_tags(tags);
|
|
}
|
|
|
|
struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
|
|
unsigned int hctx_idx,
|
|
unsigned int nr_tags,
|
|
unsigned int reserved_tags)
|
|
{
|
|
struct blk_mq_tags *tags;
|
|
int node;
|
|
|
|
node = blk_mq_hw_queue_to_node(set->mq_map, hctx_idx);
|
|
if (node == NUMA_NO_NODE)
|
|
node = set->numa_node;
|
|
|
|
tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
|
|
BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
|
|
if (!tags)
|
|
return NULL;
|
|
|
|
tags->rqs = kzalloc_node(nr_tags * sizeof(struct request *),
|
|
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
|
|
node);
|
|
if (!tags->rqs) {
|
|
blk_mq_free_tags(tags);
|
|
return NULL;
|
|
}
|
|
|
|
tags->static_rqs = kzalloc_node(nr_tags * sizeof(struct request *),
|
|
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
|
|
node);
|
|
if (!tags->static_rqs) {
|
|
kfree(tags->rqs);
|
|
blk_mq_free_tags(tags);
|
|
return NULL;
|
|
}
|
|
|
|
return tags;
|
|
}
|
|
|
|
static size_t order_to_size(unsigned int order)
|
|
{
|
|
return (size_t)PAGE_SIZE << order;
|
|
}
|
|
|
|
int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
|
|
unsigned int hctx_idx, unsigned int depth)
|
|
{
|
|
unsigned int i, j, entries_per_page, max_order = 4;
|
|
size_t rq_size, left;
|
|
int node;
|
|
|
|
node = blk_mq_hw_queue_to_node(set->mq_map, hctx_idx);
|
|
if (node == NUMA_NO_NODE)
|
|
node = set->numa_node;
|
|
|
|
INIT_LIST_HEAD(&tags->page_list);
|
|
|
|
/*
|
|
* rq_size is the size of the request plus driver payload, rounded
|
|
* to the cacheline size
|
|
*/
|
|
rq_size = round_up(sizeof(struct request) + set->cmd_size,
|
|
cache_line_size());
|
|
left = rq_size * depth;
|
|
|
|
for (i = 0; i < depth; ) {
|
|
int this_order = max_order;
|
|
struct page *page;
|
|
int to_do;
|
|
void *p;
|
|
|
|
while (this_order && left < order_to_size(this_order - 1))
|
|
this_order--;
|
|
|
|
do {
|
|
page = alloc_pages_node(node,
|
|
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO,
|
|
this_order);
|
|
if (page)
|
|
break;
|
|
if (!this_order--)
|
|
break;
|
|
if (order_to_size(this_order) < rq_size)
|
|
break;
|
|
} while (1);
|
|
|
|
if (!page)
|
|
goto fail;
|
|
|
|
page->private = this_order;
|
|
list_add_tail(&page->lru, &tags->page_list);
|
|
|
|
p = page_address(page);
|
|
/*
|
|
* Allow kmemleak to scan these pages as they contain pointers
|
|
* to additional allocations like via ops->init_request().
|
|
*/
|
|
kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO);
|
|
entries_per_page = order_to_size(this_order) / rq_size;
|
|
to_do = min(entries_per_page, depth - i);
|
|
left -= to_do * rq_size;
|
|
for (j = 0; j < to_do; j++) {
|
|
struct request *rq = p;
|
|
|
|
tags->static_rqs[i] = rq;
|
|
if (set->ops->init_request) {
|
|
if (set->ops->init_request(set, rq, hctx_idx,
|
|
node)) {
|
|
tags->static_rqs[i] = NULL;
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
p += rq_size;
|
|
i++;
|
|
}
|
|
}
|
|
return 0;
|
|
|
|
fail:
|
|
blk_mq_free_rqs(set, tags, hctx_idx);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* 'cpu' is going away. splice any existing rq_list entries from this
|
|
* software queue to the hw queue dispatch list, and ensure that it
|
|
* gets run.
|
|
*/
|
|
static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct blk_mq_ctx *ctx;
|
|
LIST_HEAD(tmp);
|
|
|
|
hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
|
|
ctx = __blk_mq_get_ctx(hctx->queue, cpu);
|
|
|
|
spin_lock(&ctx->lock);
|
|
if (!list_empty(&ctx->rq_list)) {
|
|
list_splice_init(&ctx->rq_list, &tmp);
|
|
blk_mq_hctx_clear_pending(hctx, ctx);
|
|
}
|
|
spin_unlock(&ctx->lock);
|
|
|
|
if (list_empty(&tmp))
|
|
return 0;
|
|
|
|
spin_lock(&hctx->lock);
|
|
list_splice_tail_init(&tmp, &hctx->dispatch);
|
|
spin_unlock(&hctx->lock);
|
|
|
|
blk_mq_run_hw_queue(hctx, true);
|
|
return 0;
|
|
}
|
|
|
|
static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD,
|
|
&hctx->cpuhp_dead);
|
|
}
|
|
|
|
/* hctx->ctxs will be freed in queue's release handler */
|
|
static void blk_mq_exit_hctx(struct request_queue *q,
|
|
struct blk_mq_tag_set *set,
|
|
struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
|
|
{
|
|
blk_mq_debugfs_unregister_hctx(hctx);
|
|
|
|
blk_mq_tag_idle(hctx);
|
|
|
|
if (set->ops->exit_request)
|
|
set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx);
|
|
|
|
blk_mq_sched_exit_hctx(q, hctx, hctx_idx);
|
|
|
|
if (set->ops->exit_hctx)
|
|
set->ops->exit_hctx(hctx, hctx_idx);
|
|
|
|
if (hctx->flags & BLK_MQ_F_BLOCKING)
|
|
cleanup_srcu_struct(hctx->queue_rq_srcu);
|
|
|
|
blk_mq_remove_cpuhp(hctx);
|
|
blk_free_flush_queue(hctx->fq);
|
|
sbitmap_free(&hctx->ctx_map);
|
|
}
|
|
|
|
static void blk_mq_exit_hw_queues(struct request_queue *q,
|
|
struct blk_mq_tag_set *set, int nr_queue)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
unsigned int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (i == nr_queue)
|
|
break;
|
|
blk_mq_exit_hctx(q, set, hctx, i);
|
|
}
|
|
}
|
|
|
|
static int blk_mq_init_hctx(struct request_queue *q,
|
|
struct blk_mq_tag_set *set,
|
|
struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
|
|
{
|
|
int node;
|
|
|
|
node = hctx->numa_node;
|
|
if (node == NUMA_NO_NODE)
|
|
node = hctx->numa_node = set->numa_node;
|
|
|
|
INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
|
|
spin_lock_init(&hctx->lock);
|
|
INIT_LIST_HEAD(&hctx->dispatch);
|
|
hctx->queue = q;
|
|
hctx->flags = set->flags & ~BLK_MQ_F_TAG_SHARED;
|
|
|
|
cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);
|
|
|
|
hctx->tags = set->tags[hctx_idx];
|
|
|
|
/*
|
|
* Allocate space for all possible cpus to avoid allocation at
|
|
* runtime
|
|
*/
|
|
hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *),
|
|
GFP_KERNEL, node);
|
|
if (!hctx->ctxs)
|
|
goto unregister_cpu_notifier;
|
|
|
|
if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8), GFP_KERNEL,
|
|
node))
|
|
goto free_ctxs;
|
|
|
|
hctx->nr_ctx = 0;
|
|
|
|
init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake);
|
|
INIT_LIST_HEAD(&hctx->dispatch_wait.entry);
|
|
|
|
if (set->ops->init_hctx &&
|
|
set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
|
|
goto free_bitmap;
|
|
|
|
if (blk_mq_sched_init_hctx(q, hctx, hctx_idx))
|
|
goto exit_hctx;
|
|
|
|
hctx->fq = blk_alloc_flush_queue(q, hctx->numa_node, set->cmd_size);
|
|
if (!hctx->fq)
|
|
goto sched_exit_hctx;
|
|
|
|
if (set->ops->init_request &&
|
|
set->ops->init_request(set, hctx->fq->flush_rq, hctx_idx,
|
|
node))
|
|
goto free_fq;
|
|
|
|
if (hctx->flags & BLK_MQ_F_BLOCKING)
|
|
init_srcu_struct(hctx->queue_rq_srcu);
|
|
|
|
blk_mq_debugfs_register_hctx(q, hctx);
|
|
|
|
return 0;
|
|
|
|
free_fq:
|
|
kfree(hctx->fq);
|
|
sched_exit_hctx:
|
|
blk_mq_sched_exit_hctx(q, hctx, hctx_idx);
|
|
exit_hctx:
|
|
if (set->ops->exit_hctx)
|
|
set->ops->exit_hctx(hctx, hctx_idx);
|
|
free_bitmap:
|
|
sbitmap_free(&hctx->ctx_map);
|
|
free_ctxs:
|
|
kfree(hctx->ctxs);
|
|
unregister_cpu_notifier:
|
|
blk_mq_remove_cpuhp(hctx);
|
|
return -1;
|
|
}
|
|
|
|
static void blk_mq_init_cpu_queues(struct request_queue *q,
|
|
unsigned int nr_hw_queues)
|
|
{
|
|
unsigned int i;
|
|
|
|
for_each_possible_cpu(i) {
|
|
struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
|
|
struct blk_mq_hw_ctx *hctx;
|
|
|
|
__ctx->cpu = i;
|
|
spin_lock_init(&__ctx->lock);
|
|
INIT_LIST_HEAD(&__ctx->rq_list);
|
|
__ctx->queue = q;
|
|
|
|
/* If the cpu isn't present, the cpu is mapped to first hctx */
|
|
if (!cpu_present(i))
|
|
continue;
|
|
|
|
hctx = blk_mq_map_queue(q, i);
|
|
|
|
/*
|
|
* Set local node, IFF we have more than one hw queue. If
|
|
* not, we remain on the home node of the device
|
|
*/
|
|
if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
|
|
hctx->numa_node = local_memory_node(cpu_to_node(i));
|
|
}
|
|
}
|
|
|
|
static bool __blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, int hctx_idx)
|
|
{
|
|
int ret = 0;
|
|
|
|
set->tags[hctx_idx] = blk_mq_alloc_rq_map(set, hctx_idx,
|
|
set->queue_depth, set->reserved_tags);
|
|
if (!set->tags[hctx_idx])
|
|
return false;
|
|
|
|
ret = blk_mq_alloc_rqs(set, set->tags[hctx_idx], hctx_idx,
|
|
set->queue_depth);
|
|
if (!ret)
|
|
return true;
|
|
|
|
blk_mq_free_rq_map(set->tags[hctx_idx]);
|
|
set->tags[hctx_idx] = NULL;
|
|
return false;
|
|
}
|
|
|
|
static void blk_mq_free_map_and_requests(struct blk_mq_tag_set *set,
|
|
unsigned int hctx_idx)
|
|
{
|
|
if (set->tags[hctx_idx]) {
|
|
blk_mq_free_rqs(set, set->tags[hctx_idx], hctx_idx);
|
|
blk_mq_free_rq_map(set->tags[hctx_idx]);
|
|
set->tags[hctx_idx] = NULL;
|
|
}
|
|
}
|
|
|
|
static void blk_mq_map_swqueue(struct request_queue *q)
|
|
{
|
|
unsigned int i, hctx_idx;
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct blk_mq_ctx *ctx;
|
|
struct blk_mq_tag_set *set = q->tag_set;
|
|
|
|
/*
|
|
* Avoid others reading imcomplete hctx->cpumask through sysfs
|
|
*/
|
|
mutex_lock(&q->sysfs_lock);
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
cpumask_clear(hctx->cpumask);
|
|
hctx->nr_ctx = 0;
|
|
}
|
|
|
|
/*
|
|
* Map software to hardware queues.
|
|
*
|
|
* If the cpu isn't present, the cpu is mapped to first hctx.
|
|
*/
|
|
for_each_present_cpu(i) {
|
|
hctx_idx = q->mq_map[i];
|
|
/* unmapped hw queue can be remapped after CPU topo changed */
|
|
if (!set->tags[hctx_idx] &&
|
|
!__blk_mq_alloc_rq_map(set, hctx_idx)) {
|
|
/*
|
|
* If tags initialization fail for some hctx,
|
|
* that hctx won't be brought online. In this
|
|
* case, remap the current ctx to hctx[0] which
|
|
* is guaranteed to always have tags allocated
|
|
*/
|
|
q->mq_map[i] = 0;
|
|
}
|
|
|
|
ctx = per_cpu_ptr(q->queue_ctx, i);
|
|
hctx = blk_mq_map_queue(q, i);
|
|
|
|
cpumask_set_cpu(i, hctx->cpumask);
|
|
ctx->index_hw = hctx->nr_ctx;
|
|
hctx->ctxs[hctx->nr_ctx++] = ctx;
|
|
}
|
|
|
|
mutex_unlock(&q->sysfs_lock);
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
/*
|
|
* If no software queues are mapped to this hardware queue,
|
|
* disable it and free the request entries.
|
|
*/
|
|
if (!hctx->nr_ctx) {
|
|
/* Never unmap queue 0. We need it as a
|
|
* fallback in case of a new remap fails
|
|
* allocation
|
|
*/
|
|
if (i && set->tags[i])
|
|
blk_mq_free_map_and_requests(set, i);
|
|
|
|
hctx->tags = NULL;
|
|
continue;
|
|
}
|
|
|
|
hctx->tags = set->tags[i];
|
|
WARN_ON(!hctx->tags);
|
|
|
|
/*
|
|
* Set the map size to the number of mapped software queues.
|
|
* This is more accurate and more efficient than looping
|
|
* over all possibly mapped software queues.
|
|
*/
|
|
sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
|
|
|
|
/*
|
|
* Initialize batch roundrobin counts
|
|
*/
|
|
hctx->next_cpu = cpumask_first(hctx->cpumask);
|
|
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Caller needs to ensure that we're either frozen/quiesced, or that
|
|
* the queue isn't live yet.
|
|
*/
|
|
static void queue_set_hctx_shared(struct request_queue *q, bool shared)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (shared) {
|
|
if (test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state))
|
|
atomic_inc(&q->shared_hctx_restart);
|
|
hctx->flags |= BLK_MQ_F_TAG_SHARED;
|
|
} else {
|
|
if (test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state))
|
|
atomic_dec(&q->shared_hctx_restart);
|
|
hctx->flags &= ~BLK_MQ_F_TAG_SHARED;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set,
|
|
bool shared)
|
|
{
|
|
struct request_queue *q;
|
|
|
|
lockdep_assert_held(&set->tag_list_lock);
|
|
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list) {
|
|
blk_mq_freeze_queue(q);
|
|
queue_set_hctx_shared(q, shared);
|
|
blk_mq_unfreeze_queue(q);
|
|
}
|
|
}
|
|
|
|
static void blk_mq_del_queue_tag_set(struct request_queue *q)
|
|
{
|
|
struct blk_mq_tag_set *set = q->tag_set;
|
|
|
|
mutex_lock(&set->tag_list_lock);
|
|
list_del_rcu(&q->tag_set_list);
|
|
INIT_LIST_HEAD(&q->tag_set_list);
|
|
if (list_is_singular(&set->tag_list)) {
|
|
/* just transitioned to unshared */
|
|
set->flags &= ~BLK_MQ_F_TAG_SHARED;
|
|
/* update existing queue */
|
|
blk_mq_update_tag_set_depth(set, false);
|
|
}
|
|
mutex_unlock(&set->tag_list_lock);
|
|
|
|
synchronize_rcu();
|
|
}
|
|
|
|
static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
|
|
struct request_queue *q)
|
|
{
|
|
q->tag_set = set;
|
|
|
|
mutex_lock(&set->tag_list_lock);
|
|
|
|
/*
|
|
* Check to see if we're transitioning to shared (from 1 to 2 queues).
|
|
*/
|
|
if (!list_empty(&set->tag_list) &&
|
|
!(set->flags & BLK_MQ_F_TAG_SHARED)) {
|
|
set->flags |= BLK_MQ_F_TAG_SHARED;
|
|
/* update existing queue */
|
|
blk_mq_update_tag_set_depth(set, true);
|
|
}
|
|
if (set->flags & BLK_MQ_F_TAG_SHARED)
|
|
queue_set_hctx_shared(q, true);
|
|
list_add_tail_rcu(&q->tag_set_list, &set->tag_list);
|
|
|
|
mutex_unlock(&set->tag_list_lock);
|
|
}
|
|
|
|
/*
|
|
* It is the actual release handler for mq, but we do it from
|
|
* request queue's release handler for avoiding use-after-free
|
|
* and headache because q->mq_kobj shouldn't have been introduced,
|
|
* but we can't group ctx/kctx kobj without it.
|
|
*/
|
|
void blk_mq_release(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
unsigned int i;
|
|
|
|
/* hctx kobj stays in hctx */
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (!hctx)
|
|
continue;
|
|
kobject_put(&hctx->kobj);
|
|
}
|
|
|
|
q->mq_map = NULL;
|
|
|
|
kfree(q->queue_hw_ctx);
|
|
|
|
/*
|
|
* release .mq_kobj and sw queue's kobject now because
|
|
* both share lifetime with request queue.
|
|
*/
|
|
blk_mq_sysfs_deinit(q);
|
|
|
|
free_percpu(q->queue_ctx);
|
|
}
|
|
|
|
struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
|
|
{
|
|
struct request_queue *uninit_q, *q;
|
|
|
|
uninit_q = blk_alloc_queue_node(GFP_KERNEL, set->numa_node);
|
|
if (!uninit_q)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
q = blk_mq_init_allocated_queue(set, uninit_q);
|
|
if (IS_ERR(q))
|
|
blk_cleanup_queue(uninit_q);
|
|
|
|
return q;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_init_queue);
|
|
|
|
static int blk_mq_hw_ctx_size(struct blk_mq_tag_set *tag_set)
|
|
{
|
|
int hw_ctx_size = sizeof(struct blk_mq_hw_ctx);
|
|
|
|
BUILD_BUG_ON(ALIGN(offsetof(struct blk_mq_hw_ctx, queue_rq_srcu),
|
|
__alignof__(struct blk_mq_hw_ctx)) !=
|
|
sizeof(struct blk_mq_hw_ctx));
|
|
|
|
if (tag_set->flags & BLK_MQ_F_BLOCKING)
|
|
hw_ctx_size += sizeof(struct srcu_struct);
|
|
|
|
return hw_ctx_size;
|
|
}
|
|
|
|
static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
|
|
struct request_queue *q)
|
|
{
|
|
int i, j;
|
|
struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
|
|
|
|
blk_mq_sysfs_unregister(q);
|
|
for (i = 0; i < set->nr_hw_queues; i++) {
|
|
int node;
|
|
|
|
if (hctxs[i])
|
|
continue;
|
|
|
|
node = blk_mq_hw_queue_to_node(q->mq_map, i);
|
|
hctxs[i] = kzalloc_node(blk_mq_hw_ctx_size(set),
|
|
GFP_KERNEL, node);
|
|
if (!hctxs[i])
|
|
break;
|
|
|
|
if (!zalloc_cpumask_var_node(&hctxs[i]->cpumask, GFP_KERNEL,
|
|
node)) {
|
|
kfree(hctxs[i]);
|
|
hctxs[i] = NULL;
|
|
break;
|
|
}
|
|
|
|
atomic_set(&hctxs[i]->nr_active, 0);
|
|
hctxs[i]->numa_node = node;
|
|
hctxs[i]->queue_num = i;
|
|
|
|
if (blk_mq_init_hctx(q, set, hctxs[i], i)) {
|
|
free_cpumask_var(hctxs[i]->cpumask);
|
|
kfree(hctxs[i]);
|
|
hctxs[i] = NULL;
|
|
break;
|
|
}
|
|
blk_mq_hctx_kobj_init(hctxs[i]);
|
|
}
|
|
for (j = i; j < q->nr_hw_queues; j++) {
|
|
struct blk_mq_hw_ctx *hctx = hctxs[j];
|
|
|
|
if (hctx) {
|
|
if (hctx->tags)
|
|
blk_mq_free_map_and_requests(set, j);
|
|
blk_mq_exit_hctx(q, set, hctx, j);
|
|
kobject_put(&hctx->kobj);
|
|
hctxs[j] = NULL;
|
|
|
|
}
|
|
}
|
|
q->nr_hw_queues = i;
|
|
blk_mq_sysfs_register(q);
|
|
}
|
|
|
|
struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
|
|
struct request_queue *q)
|
|
{
|
|
/* mark the queue as mq asap */
|
|
q->mq_ops = set->ops;
|
|
|
|
q->poll_cb = blk_stat_alloc_callback(blk_mq_poll_stats_fn,
|
|
blk_mq_poll_stats_bkt,
|
|
BLK_MQ_POLL_STATS_BKTS, q);
|
|
if (!q->poll_cb)
|
|
goto err_exit;
|
|
|
|
q->queue_ctx = alloc_percpu(struct blk_mq_ctx);
|
|
if (!q->queue_ctx)
|
|
goto err_exit;
|
|
|
|
/* init q->mq_kobj and sw queues' kobjects */
|
|
blk_mq_sysfs_init(q);
|
|
|
|
q->queue_hw_ctx = kzalloc_node(nr_cpu_ids * sizeof(*(q->queue_hw_ctx)),
|
|
GFP_KERNEL, set->numa_node);
|
|
if (!q->queue_hw_ctx)
|
|
goto err_percpu;
|
|
|
|
q->mq_map = set->mq_map;
|
|
|
|
blk_mq_realloc_hw_ctxs(set, q);
|
|
if (!q->nr_hw_queues)
|
|
goto err_hctxs;
|
|
|
|
INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
|
|
blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
|
|
|
|
q->nr_queues = nr_cpu_ids;
|
|
|
|
q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
|
|
|
|
if (!(set->flags & BLK_MQ_F_SG_MERGE))
|
|
q->queue_flags |= 1 << QUEUE_FLAG_NO_SG_MERGE;
|
|
|
|
q->sg_reserved_size = INT_MAX;
|
|
|
|
INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
|
|
INIT_LIST_HEAD(&q->requeue_list);
|
|
spin_lock_init(&q->requeue_lock);
|
|
|
|
blk_queue_make_request(q, blk_mq_make_request);
|
|
if (q->mq_ops->poll)
|
|
q->poll_fn = blk_mq_poll;
|
|
|
|
/*
|
|
* Do this after blk_queue_make_request() overrides it...
|
|
*/
|
|
q->nr_requests = set->queue_depth;
|
|
|
|
/*
|
|
* Default to classic polling
|
|
*/
|
|
q->poll_nsec = -1;
|
|
|
|
if (set->ops->complete)
|
|
blk_queue_softirq_done(q, set->ops->complete);
|
|
|
|
blk_mq_init_cpu_queues(q, set->nr_hw_queues);
|
|
blk_mq_add_queue_tag_set(set, q);
|
|
blk_mq_map_swqueue(q);
|
|
|
|
if (!(set->flags & BLK_MQ_F_NO_SCHED)) {
|
|
int ret;
|
|
|
|
ret = blk_mq_sched_init(q);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
return q;
|
|
|
|
err_hctxs:
|
|
kfree(q->queue_hw_ctx);
|
|
err_percpu:
|
|
free_percpu(q->queue_ctx);
|
|
err_exit:
|
|
q->mq_ops = NULL;
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_init_allocated_queue);
|
|
|
|
void blk_mq_free_queue(struct request_queue *q)
|
|
{
|
|
struct blk_mq_tag_set *set = q->tag_set;
|
|
|
|
blk_mq_del_queue_tag_set(q);
|
|
blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
|
|
}
|
|
|
|
/* Basically redo blk_mq_init_queue with queue frozen */
|
|
static void blk_mq_queue_reinit(struct request_queue *q)
|
|
{
|
|
WARN_ON_ONCE(!atomic_read(&q->mq_freeze_depth));
|
|
|
|
blk_mq_debugfs_unregister_hctxs(q);
|
|
blk_mq_sysfs_unregister(q);
|
|
|
|
/*
|
|
* redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
|
|
* we should change hctx numa_node according to the new topology (this
|
|
* involves freeing and re-allocating memory, worth doing?)
|
|
*/
|
|
blk_mq_map_swqueue(q);
|
|
|
|
blk_mq_sysfs_register(q);
|
|
blk_mq_debugfs_register_hctxs(q);
|
|
}
|
|
|
|
static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < set->nr_hw_queues; i++)
|
|
if (!__blk_mq_alloc_rq_map(set, i))
|
|
goto out_unwind;
|
|
|
|
return 0;
|
|
|
|
out_unwind:
|
|
while (--i >= 0)
|
|
blk_mq_free_rq_map(set->tags[i]);
|
|
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* Allocate the request maps associated with this tag_set. Note that this
|
|
* may reduce the depth asked for, if memory is tight. set->queue_depth
|
|
* will be updated to reflect the allocated depth.
|
|
*/
|
|
static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
|
|
{
|
|
unsigned int depth;
|
|
int err;
|
|
|
|
depth = set->queue_depth;
|
|
do {
|
|
err = __blk_mq_alloc_rq_maps(set);
|
|
if (!err)
|
|
break;
|
|
|
|
set->queue_depth >>= 1;
|
|
if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
|
|
err = -ENOMEM;
|
|
break;
|
|
}
|
|
} while (set->queue_depth);
|
|
|
|
if (!set->queue_depth || err) {
|
|
pr_err("blk-mq: failed to allocate request map\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
if (depth != set->queue_depth)
|
|
pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
|
|
depth, set->queue_depth);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int blk_mq_update_queue_map(struct blk_mq_tag_set *set)
|
|
{
|
|
if (set->ops->map_queues)
|
|
return set->ops->map_queues(set);
|
|
else
|
|
return blk_mq_map_queues(set);
|
|
}
|
|
|
|
/*
|
|
* Alloc a tag set to be associated with one or more request queues.
|
|
* May fail with EINVAL for various error conditions. May adjust the
|
|
* requested depth down, if if it too large. In that case, the set
|
|
* value will be stored in set->queue_depth.
|
|
*/
|
|
int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
|
|
{
|
|
int ret;
|
|
|
|
BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
|
|
|
|
if (!set->nr_hw_queues)
|
|
return -EINVAL;
|
|
if (!set->queue_depth)
|
|
return -EINVAL;
|
|
if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
|
|
return -EINVAL;
|
|
|
|
if (!set->ops->queue_rq)
|
|
return -EINVAL;
|
|
|
|
if (!set->ops->get_budget ^ !set->ops->put_budget)
|
|
return -EINVAL;
|
|
|
|
if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
|
|
pr_info("blk-mq: reduced tag depth to %u\n",
|
|
BLK_MQ_MAX_DEPTH);
|
|
set->queue_depth = BLK_MQ_MAX_DEPTH;
|
|
}
|
|
|
|
/*
|
|
* If a crashdump is active, then we are potentially in a very
|
|
* memory constrained environment. Limit us to 1 queue and
|
|
* 64 tags to prevent using too much memory.
|
|
*/
|
|
if (is_kdump_kernel()) {
|
|
set->nr_hw_queues = 1;
|
|
set->queue_depth = min(64U, set->queue_depth);
|
|
}
|
|
/*
|
|
* There is no use for more h/w queues than cpus.
|
|
*/
|
|
if (set->nr_hw_queues > nr_cpu_ids)
|
|
set->nr_hw_queues = nr_cpu_ids;
|
|
|
|
set->tags = kzalloc_node(nr_cpu_ids * sizeof(struct blk_mq_tags *),
|
|
GFP_KERNEL, set->numa_node);
|
|
if (!set->tags)
|
|
return -ENOMEM;
|
|
|
|
ret = -ENOMEM;
|
|
set->mq_map = kzalloc_node(sizeof(*set->mq_map) * nr_cpu_ids,
|
|
GFP_KERNEL, set->numa_node);
|
|
if (!set->mq_map)
|
|
goto out_free_tags;
|
|
|
|
ret = blk_mq_update_queue_map(set);
|
|
if (ret)
|
|
goto out_free_mq_map;
|
|
|
|
ret = blk_mq_alloc_rq_maps(set);
|
|
if (ret)
|
|
goto out_free_mq_map;
|
|
|
|
mutex_init(&set->tag_list_lock);
|
|
INIT_LIST_HEAD(&set->tag_list);
|
|
|
|
return 0;
|
|
|
|
out_free_mq_map:
|
|
kfree(set->mq_map);
|
|
set->mq_map = NULL;
|
|
out_free_tags:
|
|
kfree(set->tags);
|
|
set->tags = NULL;
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_alloc_tag_set);
|
|
|
|
void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < nr_cpu_ids; i++)
|
|
blk_mq_free_map_and_requests(set, i);
|
|
|
|
kfree(set->mq_map);
|
|
set->mq_map = NULL;
|
|
|
|
kfree(set->tags);
|
|
set->tags = NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_free_tag_set);
|
|
|
|
int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
|
|
{
|
|
struct blk_mq_tag_set *set = q->tag_set;
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i, ret;
|
|
|
|
if (!set)
|
|
return -EINVAL;
|
|
|
|
blk_mq_freeze_queue(q);
|
|
|
|
ret = 0;
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (!hctx->tags)
|
|
continue;
|
|
/*
|
|
* If we're using an MQ scheduler, just update the scheduler
|
|
* queue depth. This is similar to what the old code would do.
|
|
*/
|
|
if (!hctx->sched_tags) {
|
|
ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
|
|
false);
|
|
} else {
|
|
ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
|
|
nr, true);
|
|
}
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
if (!ret)
|
|
q->nr_requests = nr;
|
|
|
|
blk_mq_unfreeze_queue(q);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
|
|
int nr_hw_queues)
|
|
{
|
|
struct request_queue *q;
|
|
|
|
lockdep_assert_held(&set->tag_list_lock);
|
|
|
|
if (nr_hw_queues > nr_cpu_ids)
|
|
nr_hw_queues = nr_cpu_ids;
|
|
if (nr_hw_queues < 1 || nr_hw_queues == set->nr_hw_queues)
|
|
return;
|
|
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list)
|
|
blk_mq_freeze_queue(q);
|
|
|
|
set->nr_hw_queues = nr_hw_queues;
|
|
blk_mq_update_queue_map(set);
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list) {
|
|
blk_mq_realloc_hw_ctxs(set, q);
|
|
blk_mq_queue_reinit(q);
|
|
}
|
|
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list)
|
|
blk_mq_unfreeze_queue(q);
|
|
}
|
|
|
|
void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
|
|
{
|
|
mutex_lock(&set->tag_list_lock);
|
|
__blk_mq_update_nr_hw_queues(set, nr_hw_queues);
|
|
mutex_unlock(&set->tag_list_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
|
|
|
|
/* Enable polling stats and return whether they were already enabled. */
|
|
static bool blk_poll_stats_enable(struct request_queue *q)
|
|
{
|
|
if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) ||
|
|
test_and_set_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
|
|
return true;
|
|
blk_stat_add_callback(q, q->poll_cb);
|
|
return false;
|
|
}
|
|
|
|
static void blk_mq_poll_stats_start(struct request_queue *q)
|
|
{
|
|
/*
|
|
* We don't arm the callback if polling stats are not enabled or the
|
|
* callback is already active.
|
|
*/
|
|
if (!test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) ||
|
|
blk_stat_is_active(q->poll_cb))
|
|
return;
|
|
|
|
blk_stat_activate_msecs(q->poll_cb, 100);
|
|
}
|
|
|
|
static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb)
|
|
{
|
|
struct request_queue *q = cb->data;
|
|
int bucket;
|
|
|
|
for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS; bucket++) {
|
|
if (cb->stat[bucket].nr_samples)
|
|
q->poll_stat[bucket] = cb->stat[bucket];
|
|
}
|
|
}
|
|
|
|
static unsigned long blk_mq_poll_nsecs(struct request_queue *q,
|
|
struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq)
|
|
{
|
|
unsigned long ret = 0;
|
|
int bucket;
|
|
|
|
/*
|
|
* If stats collection isn't on, don't sleep but turn it on for
|
|
* future users
|
|
*/
|
|
if (!blk_poll_stats_enable(q))
|
|
return 0;
|
|
|
|
/*
|
|
* As an optimistic guess, use half of the mean service time
|
|
* for this type of request. We can (and should) make this smarter.
|
|
* For instance, if the completion latencies are tight, we can
|
|
* get closer than just half the mean. This is especially
|
|
* important on devices where the completion latencies are longer
|
|
* than ~10 usec. We do use the stats for the relevant IO size
|
|
* if available which does lead to better estimates.
|
|
*/
|
|
bucket = blk_mq_poll_stats_bkt(rq);
|
|
if (bucket < 0)
|
|
return ret;
|
|
|
|
if (q->poll_stat[bucket].nr_samples)
|
|
ret = (q->poll_stat[bucket].mean + 1) / 2;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static bool blk_mq_poll_hybrid_sleep(struct request_queue *q,
|
|
struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq)
|
|
{
|
|
struct hrtimer_sleeper hs;
|
|
enum hrtimer_mode mode;
|
|
unsigned int nsecs;
|
|
ktime_t kt;
|
|
|
|
if (test_bit(REQ_ATOM_POLL_SLEPT, &rq->atomic_flags))
|
|
return false;
|
|
|
|
/*
|
|
* poll_nsec can be:
|
|
*
|
|
* -1: don't ever hybrid sleep
|
|
* 0: use half of prev avg
|
|
* >0: use this specific value
|
|
*/
|
|
if (q->poll_nsec == -1)
|
|
return false;
|
|
else if (q->poll_nsec > 0)
|
|
nsecs = q->poll_nsec;
|
|
else
|
|
nsecs = blk_mq_poll_nsecs(q, hctx, rq);
|
|
|
|
if (!nsecs)
|
|
return false;
|
|
|
|
set_bit(REQ_ATOM_POLL_SLEPT, &rq->atomic_flags);
|
|
|
|
/*
|
|
* This will be replaced with the stats tracking code, using
|
|
* 'avg_completion_time / 2' as the pre-sleep target.
|
|
*/
|
|
kt = nsecs;
|
|
|
|
mode = HRTIMER_MODE_REL;
|
|
hrtimer_init_on_stack(&hs.timer, CLOCK_MONOTONIC, mode);
|
|
hrtimer_set_expires(&hs.timer, kt);
|
|
|
|
hrtimer_init_sleeper(&hs, current);
|
|
do {
|
|
if (test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags))
|
|
break;
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
hrtimer_start_expires(&hs.timer, mode);
|
|
if (hs.task)
|
|
io_schedule();
|
|
hrtimer_cancel(&hs.timer);
|
|
mode = HRTIMER_MODE_ABS;
|
|
} while (hs.task && !signal_pending(current));
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
destroy_hrtimer_on_stack(&hs.timer);
|
|
return true;
|
|
}
|
|
|
|
static bool __blk_mq_poll(struct blk_mq_hw_ctx *hctx, struct request *rq)
|
|
{
|
|
struct request_queue *q = hctx->queue;
|
|
long state;
|
|
|
|
/*
|
|
* If we sleep, have the caller restart the poll loop to reset
|
|
* the state. Like for the other success return cases, the
|
|
* caller is responsible for checking if the IO completed. If
|
|
* the IO isn't complete, we'll get called again and will go
|
|
* straight to the busy poll loop.
|
|
*/
|
|
if (blk_mq_poll_hybrid_sleep(q, hctx, rq))
|
|
return true;
|
|
|
|
hctx->poll_considered++;
|
|
|
|
state = current->state;
|
|
while (!need_resched()) {
|
|
int ret;
|
|
|
|
hctx->poll_invoked++;
|
|
|
|
ret = q->mq_ops->poll(hctx, rq->tag);
|
|
if (ret > 0) {
|
|
hctx->poll_success++;
|
|
set_current_state(TASK_RUNNING);
|
|
return true;
|
|
}
|
|
|
|
if (signal_pending_state(state, current))
|
|
set_current_state(TASK_RUNNING);
|
|
|
|
if (current->state == TASK_RUNNING)
|
|
return true;
|
|
if (ret < 0)
|
|
break;
|
|
cpu_relax();
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct request *rq;
|
|
|
|
if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
|
|
return false;
|
|
|
|
hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)];
|
|
if (!blk_qc_t_is_internal(cookie))
|
|
rq = blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(cookie));
|
|
else {
|
|
rq = blk_mq_tag_to_rq(hctx->sched_tags, blk_qc_t_to_tag(cookie));
|
|
/*
|
|
* With scheduling, if the request has completed, we'll
|
|
* get a NULL return here, as we clear the sched tag when
|
|
* that happens. The request still remains valid, like always,
|
|
* so we should be safe with just the NULL check.
|
|
*/
|
|
if (!rq)
|
|
return false;
|
|
}
|
|
|
|
return __blk_mq_poll(hctx, rq);
|
|
}
|
|
|
|
static int __init blk_mq_init(void)
|
|
{
|
|
/*
|
|
* See comment in block/blk.h rq_atomic_flags enum
|
|
*/
|
|
BUILD_BUG_ON((REQ_ATOM_STARTED / BITS_PER_BYTE) !=
|
|
(REQ_ATOM_COMPLETE / BITS_PER_BYTE));
|
|
|
|
cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
|
|
blk_mq_hctx_notify_dead);
|
|
return 0;
|
|
}
|
|
subsys_initcall(blk_mq_init);
|