block: support polling through blk_execute_rq

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

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210610214437.641245-2-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-exec.c b/block/blk-exec.c
index beae70a0e5e5033a6a1684a481b44783fc874f2a..38f88552aa317dada200a8dc7488765476f46d28 100644 (file)
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -63,6 +63,19 @@ 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;
+}
+
+static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
+{
+       do {
+               blk_poll(rq->q, request_to_qc_t(rq->mq_hctx, rq), true);
+               cond_resched();
+       } while (!completion_done(wait));
+}
+
 /**
  * blk_execute_rq - insert a request into queue for execution
  * @bd_disk:   matching gendisk
@@ -83,7 +96,10 @@ 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))
+               blk_rq_poll_completion(rq, &wait);
+       else if (hang_check)
                while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
        else
                wait_for_completion_io(&wait);