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| author | Jens Axboe <axboe@fb.com> | 2014-04-24 08:51:47 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-04-24 08:51:47 -0600 |
| commit | 87ee7b112193bd081ba1a171fa5f6f39c429ef56 (patch) | |
| tree | fbf88d2de279209467dee4d6cd9007f5daa8a678 /block/blk-timeout.c | |
| parent | 70ab0b2d51f84fc7d9eb6ed81c3986595efaa33d (diff) | |
| download | lwn-87ee7b112193bd081ba1a171fa5f6f39c429ef56.tar.gz lwn-87ee7b112193bd081ba1a171fa5f6f39c429ef56.zip | |
blk-mq: fix race with timeouts and requeue events
If a requeue event races with a timeout, we can get into the
situation where we attempt to complete a request from the
timeout handler when it's not start anymore. This causes a crash.
So have the timeout handler check that REQ_ATOM_STARTED is still
set on the request - if not, we ignore the event. If this happens,
the request has now been marked as complete. As a consequence, we
need to ensure to clear REQ_ATOM_COMPLETE in blk_mq_start_request(),
as to maintain proper request state.
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-timeout.c')
| -rw-r--r-- | block/blk-timeout.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/block/blk-timeout.c b/block/blk-timeout.c index a09e8af8186c..49988a3ca85c 100644 --- a/block/blk-timeout.c +++ b/block/blk-timeout.c @@ -96,11 +96,7 @@ static void blk_rq_timed_out(struct request *req) __blk_complete_request(req); break; case BLK_EH_RESET_TIMER: - if (q->mq_ops) - blk_mq_add_timer(req); - else - blk_add_timer(req); - + blk_add_timer(req); blk_clear_rq_complete(req); break; case BLK_EH_NOT_HANDLED: @@ -170,7 +166,8 @@ void blk_abort_request(struct request *req) } EXPORT_SYMBOL_GPL(blk_abort_request); -void __blk_add_timer(struct request *req, struct list_head *timeout_list) +static void __blk_add_timer(struct request *req, + struct list_head *timeout_list) { struct request_queue *q = req->q; unsigned long expiry; @@ -225,6 +222,11 @@ void __blk_add_timer(struct request *req, struct list_head *timeout_list) */ void blk_add_timer(struct request *req) { - __blk_add_timer(req, &req->q->timeout_list); + struct request_queue *q = req->q; + + if (q->mq_ops) + __blk_add_timer(req, NULL); + else + __blk_add_timer(req, &req->q->timeout_list); } |