From: Jens Axboe <axboe@kernel.dk>
Date: Wed, 3 Nov 2021 05:47:09 -0600
Subject: [PATCH] block: move queue enter logic into blk_mq_submit_bio()
Git-commit: 900e080752025f0016128f07c9ed4c50eba3654b
Patch-mainline: v5.16-rc1
References: jsc#PED-1183
Retain the old logic for the fops based submit, but for our internal
blk_mq_submit_bio(), move the queue entering logic into the core
function itself.
We need to be a bit careful if going into the scheduler, as a scheduler
or queue mappings can arbitrarily change before we have entered the queue.
Have the bio scheduler mapping do that separately, it's a very cheap
operation compared to actually doing merging locking and lookups.
Reviewed-by: Christoph Hellwig <hch@lst.de>
[axboe: update to check merge post submit_bio_checks() doing remap...]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
block/blk-core.c | 25 +++++++++---------
block/blk-mq-sched.c | 13 +++++++---
block/blk-mq.c | 60 ++++++++++++++++++++++++++++++--------------
block/blk.h | 1 +
4 files changed, 65 insertions(+), 34 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 9ca3ddd154d4..4366056e14c4 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -744,7 +744,7 @@ static inline blk_status_t blk_check_zone_append(struct request_queue *q,
return BLK_STS_OK;
}
-static noinline_for_stack bool submit_bio_checks(struct bio *bio)
+noinline_for_stack bool submit_bio_checks(struct bio *bio)
{
struct block_device *bdev = bio->bi_bdev;
struct request_queue *q = bdev_get_queue(bdev);
@@ -862,22 +862,23 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio)
return false;
}
-static void __submit_bio(struct bio *bio)
+static void __submit_bio_fops(struct gendisk *disk, struct bio *bio)
{
- struct gendisk *disk = bio->bi_bdev->bd_disk;
-
if (unlikely(bio_queue_enter(bio) != 0))
return;
+ if (submit_bio_checks(bio) && blk_crypto_bio_prep(&bio))
+ disk->fops->submit_bio(bio);
+ blk_queue_exit(disk->queue);
+}
- if (!submit_bio_checks(bio) || !blk_crypto_bio_prep(&bio))
- goto queue_exit;
- if (!disk->fops->submit_bio) {
+static void __submit_bio(struct bio *bio)
+{
+ struct gendisk *disk = bio->bi_bdev->bd_disk;
+
+ if (!disk->fops->submit_bio)
blk_mq_submit_bio(bio);
- return;
- }
- disk->fops->submit_bio(bio);
-queue_exit:
- blk_queue_exit(disk->queue);
+ else
+ __submit_bio_fops(disk, bio);
}
/*
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 4a6789e4398b..4be652fa38e7 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -370,15 +370,20 @@ bool blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio,
bool ret = false;
enum hctx_type type;
- if (e && e->type->ops.bio_merge)
- return e->type->ops.bio_merge(q, bio, nr_segs);
+ if (bio_queue_enter(bio))
+ return false;
+
+ if (e && e->type->ops.bio_merge) {
+ ret = e->type->ops.bio_merge(q, bio, nr_segs);
+ goto out_put;
+ }
ctx = blk_mq_get_ctx(q);
hctx = blk_mq_map_queue(q, bio->bi_opf, ctx);
type = hctx->type;
if (!(hctx->flags & BLK_MQ_F_SHOULD_MERGE) ||
list_empty_careful(&ctx->rq_lists[type]))
- return false;
+ goto out_put;
/* default per sw-queue merge */
spin_lock(&ctx->lock);
@@ -391,6 +396,8 @@ bool blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio,
ret = true;
spin_unlock(&ctx->lock);
+out_put:
+ blk_queue_exit(q);
return ret;
}
diff --git a/block/blk-mq.c b/block/blk-mq.c
index dcb413297a96..5fe40c85a308 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2478,9 +2478,23 @@ static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug)
return BLK_MAX_REQUEST_COUNT;
}
+static bool blk_attempt_bio_merge(struct request_queue *q, struct bio *bio,
+ unsigned int nr_segs, bool *same_queue_rq)
+{
+ if (!blk_queue_nomerges(q) && bio_mergeable(bio)) {
+ if (blk_attempt_plug_merge(q, bio, nr_segs, same_queue_rq))
+ return true;
+ if (blk_mq_sched_bio_merge(q, bio, nr_segs))
+ return true;
+ }
+ return false;
+}
+
static struct request *blk_mq_get_new_requests(struct request_queue *q,
struct blk_plug *plug,
- struct bio *bio)
+ struct bio *bio,
+ unsigned int nsegs,
+ bool *same_queue_rq)
{
struct blk_mq_alloc_data data = {
.q = q,
@@ -2489,6 +2503,15 @@ static struct request *blk_mq_get_new_requests(struct request_queue *q,
};
struct request *rq;
+ if (unlikely(bio_queue_enter(bio)))
+ return NULL;
+ if (unlikely(!submit_bio_checks(bio)))
+ goto put_exit;
+ if (blk_attempt_bio_merge(q, bio, nsegs, same_queue_rq))
+ goto put_exit;
+
+ rq_qos_throttle(q, bio);
+
if (plug) {
data.nr_tags = plug->nr_ios;
plug->nr_ios = 1;
@@ -2502,25 +2525,34 @@ static struct request *blk_mq_get_new_requests(struct request_queue *q,
rq_qos_cleanup(q, bio);
if (bio->bi_opf & REQ_NOWAIT)
bio_wouldblock_error(bio);
+put_exit:
+ blk_queue_exit(q);
return NULL;
}
static inline struct request *blk_mq_get_request(struct request_queue *q,
struct blk_plug *plug,
- struct bio *bio)
+ struct bio *bio,
+ unsigned int nsegs,
+ bool *same_queue_rq)
{
if (plug) {
struct request *rq;
rq = rq_list_peek(&plug->cached_rq);
if (rq) {
+ if (unlikely(!submit_bio_checks(bio)))
+ return NULL;
+ if (blk_attempt_bio_merge(q, bio, nsegs, same_queue_rq))
+ return NULL;
plug->cached_rq = rq_list_next(rq);
INIT_LIST_HEAD(&rq->queuelist);
+ rq_qos_throttle(q, bio);
return rq;
}
}
- return blk_mq_get_new_requests(q, plug, bio);
+ return blk_mq_get_new_requests(q, plug, bio, nsegs, same_queue_rq);
}
/**
@@ -2546,26 +2578,20 @@ void blk_mq_submit_bio(struct bio *bio)
unsigned int nr_segs = 1;
blk_status_t ret;
+ if (unlikely(!blk_crypto_bio_prep(&bio)))
+ return;
+
blk_queue_bounce(q, &bio);
if (blk_may_split(q, bio))
__blk_queue_split(q, &bio, &nr_segs);
if (!bio_integrity_prep(bio))
- goto queue_exit;
-
- if (!blk_queue_nomerges(q) && bio_mergeable(bio)) {
- if (blk_attempt_plug_merge(q, bio, nr_segs, &same_queue_rq))
- goto queue_exit;
- if (blk_mq_sched_bio_merge(q, bio, nr_segs))
- goto queue_exit;
- }
-
- rq_qos_throttle(q, bio);
+ return;
plug = blk_mq_plug(q, bio);
- rq = blk_mq_get_request(q, plug, bio);
+ rq = blk_mq_get_request(q, plug, bio, nr_segs, &same_queue_rq);
if (unlikely(!rq))
- goto queue_exit;
+ return;
trace_block_getrq(bio);
@@ -2646,10 +2672,6 @@ void blk_mq_submit_bio(struct bio *bio)
/* Default case. */
blk_mq_sched_insert_request(rq, false, true, true);
}
-
- return;
-queue_exit:
- blk_queue_exit(q);
}
static size_t order_to_size(unsigned int order)
diff --git a/block/blk.h b/block/blk.h
index 814d9632d43e..b4fed2033e48 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -56,6 +56,7 @@ void blk_freeze_queue(struct request_queue *q);
void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic);
void blk_queue_start_drain(struct request_queue *q);
int __bio_queue_enter(struct request_queue *q, struct bio *bio);
+bool submit_bio_checks(struct bio *bio);
static inline bool blk_try_enter_queue(struct request_queue *q, bool pm)
{
--
2.35.3