blk-mq: when polling for IO, look for any completion

If we want to support async IO polling, then we have to allow finding
completions that aren't just for the one we are looking for. Always pass
in -1 to the mq_ops->poll() helper, and have that return how many events
were found in this poll loop.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 11 insertions, 2 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 04f5be473638..03c4202b69bf 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1273,10 +1273,19 @@ blk_qc_t submit_bio(struct bio *bio)
 }
 EXPORT_SYMBOL(submit_bio);
 
-bool blk_poll(struct request_queue *q, blk_qc_t cookie)
+/**
+ * blk_poll - poll for IO completions
+ * @q:  the queue
+ * @cookie: cookie passed back at IO submission time
+ *
+ * Description:
+ *    Poll for completions on the passed in queue. Returns number of
+ *    completed entries found.
+ */
+int blk_poll(struct request_queue *q, blk_qc_t cookie)
 {
 	if (!q->poll_fn || !blk_qc_t_valid(cookie))
-		return false;
+		return 0;
 
 	if (current->plug)
 		blk_flush_plug_list(current->plug, false);