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authorMing Lei <ming.lei@redhat.com>2019-04-09 06:31:21 +0800
committerJens Axboe <axboe@kernel.dk>2019-04-10 09:57:33 -0600
commit1b8f21b74c3c9c82fce5a751d7aefb7cc0b8d33d (patch)
treeb6e8eac9fe39c7d114587047c6addc7728009bbd /block
parent1978f30a87732d4d9072a20abeded9fe17884f1b (diff)
downloadlwn-1b8f21b74c3c9c82fce5a751d7aefb7cc0b8d33d.tar.gz
lwn-1b8f21b74c3c9c82fce5a751d7aefb7cc0b8d33d.zip
blk-mq: introduce blk_mq_complete_request_sync()
In NVMe's error handler, follows the typical steps of tearing down hardware for recovering controller: 1) stop blk_mq hw queues 2) stop the real hw queues 3) cancel in-flight requests via blk_mq_tagset_busy_iter(tags, cancel_request, ...) cancel_request(): mark the request as abort blk_mq_complete_request(req); 4) destroy real hw queues However, there may be race between #3 and #4, because blk_mq_complete_request() may run q->mq_ops->complete(rq) remotelly and asynchronously, and ->complete(rq) may be run after #4. This patch introduces blk_mq_complete_request_sync() for fixing the above race. Cc: Sagi Grimberg <sagi@grimberg.me> Cc: Bart Van Assche <bvanassche@acm.org> Cc: James Smart <james.smart@broadcom.com> Cc: linux-nvme@lists.infradead.org Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index a9354835cf51..9516304a38ee 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -654,6 +654,13 @@ bool blk_mq_complete_request(struct request *rq)
}
EXPORT_SYMBOL(blk_mq_complete_request);
+void blk_mq_complete_request_sync(struct request *rq)
+{
+ WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
+ rq->q->mq_ops->complete(rq);
+}
+EXPORT_SYMBOL_GPL(blk_mq_complete_request_sync);
+
int blk_mq_request_started(struct request *rq)
{
return blk_mq_rq_state(rq) != MQ_RQ_IDLE;