From: Jeff Moyer <jmo...@redhat.com>
Request queues with merging disabled will not flush the plug list after
BLK_MAX_REQUEST_COUNT requests have been queued, since the code relies
on blk_attempt_plug_merge to compute the request_count. Fix this by
computing the number of queued requests even for nomerge queues.
Signed-off-by: Jeff Moyer <jmo...@redhat.com>
---
block/blk-core.c | 32 +++++++++++++++++++++++++++++---
block/blk-mq.c | 9 ++++++---
block/blk.h | 1 +
3 files changed, 36 insertions(+), 6 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 0391206..4a45d00 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1594,6 +1594,30 @@ out:
return ret;
}
+unsigned int blk_plug_queued_count(struct request_queue *q)
+{
+ struct blk_plug *plug;
+ struct request *rq;
+ struct list_head *plug_list;
+ unsigned int ret = 0;
+
+ plug = current->plug;
+ if (!plug)
+ goto out;
+
+ if (q->mq_ops)
+ plug_list = &plug->mq_list;
+ else
+ plug_list = &plug->list;
+
+ list_for_each_entry(rq, plug_list, queuelist) {
+ if (rq->q == q)
+ ret++;
+ }
+out:
+ return ret;
+}
+
void init_request_from_bio(struct request *req, struct bio *bio)
{
req->cmd_type = REQ_TYPE_FS;
@@ -1641,9 +1665,11 @@ static void blk_queue_bio(struct request_queue *q,
struct bio *bio)
* Check if we can merge with the plugged list before grabbing
* any locks.
*/
- if (!blk_queue_nomerges(q) &&
- blk_attempt_plug_merge(q, bio, &request_count, NULL))
- return;
+ if (!blk_queue_nomerges(q)) {
+ if (blk_attempt_plug_merge(q, bio, &request_count, NULL))
+ return;
+ } else
+ request_count = blk_plug_queued_count(q);
spin_lock_irq(q->queue_lock);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 546b3b8..1796b31 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1268,9 +1268,12 @@ static void blk_mq_make_request(struct request_queue *q,
struct bio *bio)
blk_queue_split(q, &bio, q->bio_split);
- if (!is_flush_fua && !blk_queue_nomerges(q) &&
- blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq))
- return;
+ if (!is_flush_fua && !blk_queue_nomerges(q)) {
+ if (blk_attempt_plug_merge(q, bio, &request_count,
+ &same_queue_rq))
+ return;
+ } else
+ request_count = blk_plug_queued_count(q);
rq = blk_mq_map_request(q, bio, &data);
if (unlikely(!rq))
diff --git a/block/blk.h b/block/blk.h
index 98614ad..aa27d02 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -86,6 +86,7 @@ bool bio_attempt_back_merge(struct request_queue *q, struct
request *req,
bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
unsigned int *request_count,
struct request **same_queue_rq);
+unsigned int blk_plug_queued_count(struct request_queue *q);
void blk_account_io_start(struct request *req, bool new_io);
void blk_account_io_completion(struct request *req, unsigned int bytes);
--
1.9.1
--
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