block: Remove code handling bio_alloc failure with __GFP_WAIT

Remove code handling bio_alloc failure with __GFP_WAIT.
GFP_KERNEL implies __GFP_WAIT.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index f7dae57..20b4111 100644
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -319,9 +319,6 @@
 		return -ENXIO;
 
 	bio = bio_alloc(GFP_KERNEL, 0);
-	if (!bio)
-		return -ENOMEM;
-
 	bio->bi_end_io = bio_end_empty_barrier;
 	bio->bi_private = &wait;
 	bio->bi_bdev = bdev;
diff --git a/block/ioctl.c b/block/ioctl.c
index 0f22e62..ad474d4 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -146,8 +146,6 @@
 		struct bio *bio;
 
 		bio = bio_alloc(GFP_KERNEL, 0);
-		if (!bio)
-			return -ENOMEM;
 
 		bio->bi_end_io = blk_ioc_discard_endio;
 		bio->bi_bdev = bdev;