[PATCH 5/6] blk-mq: ensure mq_ops ->poll() is entered at least once

[Jens Axboe]

Right now we immediately bail if need_resched() is true, but
we need to do at least one loop in case we have entries waiting.
So just invert the need_resched() check, putting it at the
bottom of the loop.

Reviewed-by: Christoph Hellwig <h...@lst.de>
Signed-off-by: Jens Axboe <ax...@kernel.dk>
---
 block/blk-mq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index c2751f0a3ccc..ba3c7b6476b7 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3375,7 +3375,7 @@ static int blk_mq_poll(struct request_queue *q, blk_qc_t 
cookie, bool spin)
        hctx->poll_considered++;
 
        state = current->state;
-       while (!need_resched()) {
+       do {
                int ret;
 
                hctx->poll_invoked++;
@@ -3395,7 +3395,7 @@ static int blk_mq_poll(struct request_queue *q, blk_qc_t 
cookie, bool spin)
                if (ret < 0 || !spin)
                        break;
                cpu_relax();
-       }
+       } while (!need_resched());
 
        __set_current_state(TASK_RUNNING);
        return 0;
-- 
2.17.1