lkml.org 
[lkml]   [2022]   [Sep]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 5.19 18/38] block: blk_queue_enter() / __bio_queue_enter() must return -EAGAIN for nowait
Date
From: Stefan Roesch <shr@fb.com>

[ Upstream commit 56f99b8d06ef1ed1c9730948f9f05ac2b930a20b ]

Today blk_queue_enter() and __bio_queue_enter() return -EBUSY for the
nowait code path. This is not correct: they should return -EAGAIN
instead.

This problem was detected by fio. The following command exposed the
above problem:

t/io_uring -p0 -d128 -b4096 -s32 -c32 -F1 -B0 -R0 -X1 -n24 -P1 -u1 -O0 /dev/ng0n1

By applying the patch, the retry case is handled correctly in the slow
path.

Signed-off-by: Stefan Roesch <shr@fb.com>
Fixes: bfd343aa1718 ("blk-mq: don't wait in blk_mq_queue_enter() if __GFP_WAIT isn't set")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/blk-core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 27fb1357ad4b..cc6fbcb6d252 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -338,7 +338,7 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)

while (!blk_try_enter_queue(q, pm)) {
if (flags & BLK_MQ_REQ_NOWAIT)
- return -EBUSY;
+ return -EAGAIN;

/*
* read pair of barrier in blk_freeze_queue_start(), we need to
@@ -368,7 +368,7 @@ int __bio_queue_enter(struct request_queue *q, struct bio *bio)
if (test_bit(GD_DEAD, &disk->state))
goto dead;
bio_wouldblock_error(bio);
- return -EBUSY;
+ return -EAGAIN;
}

/*
--
2.35.1


\
 
 \ /
  Last update: 2022-09-21 17:50    [W:0.126 / U:0.736 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site