[PATCHv2 1/5] block: support polling through blk_execute_rq

[Keith Busch]

Poll for completions if the request's hctx is a polling type.

Signed-off-by: Keith Busch <kbusch at kernel.org>
---
 block/blk-exec.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/block/blk-exec.c b/block/blk-exec.c
index beae70a0e5e5..b960ad187ba5 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -63,6 +63,11 @@ void blk_execute_rq_nowait(struct gendisk *bd_disk, struct request *rq,
 }
 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
 
+static bool blk_rq_is_poll(struct request *rq)
+{
+	return rq->mq_hctx && rq->mq_hctx->type == HCTX_TYPE_POLL;
+}
+
 /**
  * blk_execute_rq - insert a request into queue for execution
  * @bd_disk:	matching gendisk
@@ -83,7 +88,12 @@ void blk_execute_rq(struct gendisk *bd_disk, struct request *rq, int at_head)
 
 	/* Prevent hang_check timer from firing at us during very long I/O */
 	hang_check = sysctl_hung_task_timeout_secs;
-	if (hang_check)
+	if (blk_rq_is_poll(rq)) {
+		do {
+			blk_poll(rq->q, request_to_qc_t(rq->mq_hctx, rq), true);
+			cond_resched();
+		} while (!completion_done(&wait));
+	} else if (hang_check)
 		while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
 	else
 		wait_for_completion_io(&wait);
-- 
2.25.4