md: remove md_bio_alloc_sync

md_bio_alloc_sync is never called with a NULL mddev, and ->sync_set is
initialized in md_run, so it always must be initialized as well.  Just
open code the remaining call to bio_alloc_bioset.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NSong Liu <song@kernel.org>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: NDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

drivers/md/md.c

@@ -340,14 +340,6 @@ static int start_readonly;
  */
 static bool create_on_open = true;
 
-static struct bio *md_bio_alloc_sync(struct mddev *mddev)
-{
-	if (!mddev || !bioset_initialized(&mddev->sync_set))
-		return bio_alloc(GFP_NOIO, 1);
-
-	return bio_alloc_bioset(GFP_NOIO, 1, &mddev->sync_set);
-}
-
 /*
  * We have a system wide 'event count' that is incremented
  * on any 'interesting' event, and readers of /proc/mdstat
@@ -989,7 +981,7 @@ void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
 	if (test_bit(Faulty, &rdev->flags))
 		return;
 
-	bio = md_bio_alloc_sync(mddev);
+	bio = bio_alloc_bioset(GFP_NOIO, 1, &mddev->sync_set);
 
 	atomic_inc(&rdev->nr_pending);