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>
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index a295b98..1c9e4fe 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -289,7 +289,7 @@
case NULL_IRQ_SOFTIRQ:
switch (queue_mode) {
case NULL_Q_MQ:
- blk_mq_complete_request(cmd->rq);
+ blk_mq_complete_request(cmd->rq, cmd->rq->errors);
break;
case NULL_Q_RQ:
blk_complete_request(cmd->rq);