blk-mq: Micro-optimize bt_get()

Remove a superfluous finish_wait() call. Convert the two bt_wait_ptr()
calls into a single call.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Robert Elliott <elliott@hp.com>
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 1 insertions, 3 deletions

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index e47c4c75fd33..1b7229f9354a 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -248,8 +248,8 @@ static int bt_get(struct blk_mq_alloc_data *data,
         if (!(data->gfp & __GFP_WAIT))
                 return -1;
 
-        bs = bt_wait_ptr(bt, hctx);
         do {
+                bs = bt_wait_ptr(bt, hctx);
                 prepare_to_wait(&bs->wait, &wait, TASK_UNINTERRUPTIBLE);
 
                 tag = __bt_get(hctx, bt, last_tag);
@@ -285,8 +285,6 @@ static int bt_get(struct blk_mq_alloc_data *data,
                         hctx = data->hctx;
                         bt = &hctx->tags->bitmap_tags;
                 }
-                finish_wait(&bs->wait, &wait);
-                bs = bt_wait_ptr(bt, hctx);
         } while (1);
 
         finish_wait(&bs->wait, &wait);