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authorJens Axboe <axboe@fb.com>2014-04-24 08:51:47 -0600
committerJens Axboe <axboe@fb.com>2014-04-24 08:51:47 -0600
commit87ee7b112193bd081ba1a171fa5f6f39c429ef56 (patch)
treefbf88d2de279209467dee4d6cd9007f5daa8a678 /block/blk-timeout.c
parent70ab0b2d51f84fc7d9eb6ed81c3986595efaa33d (diff)
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.c16
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);
}