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authorChristoph Hellwig <hch@lst.de>2015-09-27 21:01:50 +0200
committerJens Axboe <axboe@fb.com>2015-10-01 10:10:55 +0200
commitf4829a9b7a61e159367350008a608b062c4f6840 (patch)
treea2f488a95324e0c0b558273f48b18413ab2fa221 /block/blk-mq.c
parentblk-mq: fix deadlock when reading cpu_list (diff)
downloadlinux-f4829a9b7a61e159367350008a608b062c4f6840.tar.xz
linux-f4829a9b7a61e159367350008a608b062c4f6840.zip
blk-mq: fix racy updates of rq->errors
blk_mq_complete_request may be a no-op if the request has already been completed by others means (e.g. a timeout or cancellation), but currently drivers have to set rq->errors before calling blk_mq_complete_request, which might leave us with the wrong error value. Add an error parameter to blk_mq_complete_request so that we can defer setting rq->errors until we known we won the race to complete the request. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-mq.c')
-rw-r--r--block/blk-mq.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 31c0c6259c4c..2306330530e8 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -393,14 +393,16 @@ void __blk_mq_complete_request(struct request *rq)
* 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)
+void blk_mq_complete_request(struct request *rq, int error)
{
struct request_queue *q = rq->q;
if (unlikely(blk_should_fake_timeout(q)))
return;
- if (!blk_mark_rq_complete(rq))
+ if (!blk_mark_rq_complete(rq)) {
+ rq->errors = error;
__blk_mq_complete_request(rq);
+ }
}
EXPORT_SYMBOL(blk_mq_complete_request);
@@ -616,10 +618,8 @@ static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
* If a request wasn't started before the queue was
* marked dying, kill it here or it'll go unnoticed.
*/
- if (unlikely(blk_queue_dying(rq->q))) {
- rq->errors = -EIO;
- blk_mq_complete_request(rq);
- }
+ if (unlikely(blk_queue_dying(rq->q)))
+ blk_mq_complete_request(rq, -EIO);
return;
}
if (rq->cmd_flags & REQ_NO_TIMEOUT)