block: use an on-stack bio in blkdev_issue_flush

There is no point in allocating memory for a synchronous flush.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 6 insertions, 11 deletions

diff --git a/block/blk-flush.c b/block/blk-flush.c
index 76c1624cb06c..7942ca6ed321 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -432,23 +432,18 @@ void blk_insert_flush(struct request *rq)
 /**
  * blkdev_issue_flush - queue a flush
  * @bdev:	blockdev to issue flush for
- * @gfp_mask:	memory allocation flags (for bio_alloc)
  *
  * Description:
  *    Issue a flush for the block device in question.
  */
-int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask)
+int blkdev_issue_flush(struct block_device *bdev)
 {
-	struct bio *bio;
-	int ret = 0;
+	struct bio bio;
 
-	bio = bio_alloc(gfp_mask, 0);
-	bio_set_dev(bio, bdev);
-	bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
-
-	ret = submit_bio_wait(bio);
-	bio_put(bio);
-	return ret;
+	bio_init(&bio, NULL, 0);
+	bio_set_dev(&bio, bdev);
+	bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
+	return submit_bio_wait(&bio);
 }
 EXPORT_SYMBOL(blkdev_issue_flush);