From 31e34732656a1263e3426d0479aca88bda87451d Mon Sep 17 00:00:00 2001
From: Shaohua Li <shli@kernel.org>
Date: Fri, 28 Sep 2012 10:38:48 +0200
Subject: [PATCH] --- yaml --- r: 333263 b: refs/heads/master c:
 02f3939e1a9357b7c370a4a69717cf9c02452737 h: refs/heads/master i:   333261:
 631c53453bce0343163fcd1da58f99bf270fe6e3   333259:
 ae01aef2e4eb0bdcec324a1fdfda54d58a007d72   333255:
 d610329cf17917197355757f5cbc756f068eaa6e   333247:
 385c10f5f856958010f52f15825c47f170e627df v: v3

---
 [refs]         |  2 +-
 trunk/fs/bio.c | 26 ++++++++++++++------------
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/[refs] b/[refs]
index 164b51ec29fc..01982b3376b0 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 232f1b51062553b7cf49f99719fbd1b8a8d80f29
+refs/heads/master: 02f3939e1a9357b7c370a4a69717cf9c02452737
diff --git a/trunk/fs/bio.c b/trunk/fs/bio.c
index f855e0e1869c..9298c65ad9c7 100644
--- a/trunk/fs/bio.c
+++ b/trunk/fs/bio.c
@@ -1475,7 +1475,7 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors)
 	trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
 				bi->bi_sector + first_sectors);
 
-	BUG_ON(bi->bi_vcnt != 1);
+	BUG_ON(bi->bi_vcnt != 1 && bi->bi_vcnt != 0);
 	BUG_ON(bi->bi_idx != 0);
 	atomic_set(&bp->cnt, 3);
 	bp->error = 0;
@@ -1485,20 +1485,22 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors)
 	bp->bio2.bi_size -= first_sectors << 9;
 	bp->bio1.bi_size = first_sectors << 9;
 
-	bp->bv1 = bi->bi_io_vec[0];
-	bp->bv2 = bi->bi_io_vec[0];
+	if (bi->bi_vcnt != 0) {
+		bp->bv1 = bi->bi_io_vec[0];
+		bp->bv2 = bi->bi_io_vec[0];
 
-	if (bio_is_rw(bi)) {
-		bp->bv2.bv_offset += first_sectors << 9;
-		bp->bv2.bv_len -= first_sectors << 9;
-		bp->bv1.bv_len = first_sectors << 9;
-	}
+		if (bio_is_rw(bi)) {
+			bp->bv2.bv_offset += first_sectors << 9;
+			bp->bv2.bv_len -= first_sectors << 9;
+			bp->bv1.bv_len = first_sectors << 9;
+		}
 
-	bp->bio1.bi_io_vec = &bp->bv1;
-	bp->bio2.bi_io_vec = &bp->bv2;
+		bp->bio1.bi_io_vec = &bp->bv1;
+		bp->bio2.bi_io_vec = &bp->bv2;
 
-	bp->bio1.bi_max_vecs = 1;
-	bp->bio2.bi_max_vecs = 1;
+		bp->bio1.bi_max_vecs = 1;
+		bp->bio2.bi_max_vecs = 1;
+	}
 
 	bp->bio1.bi_end_io = bio_pair_end_1;
 	bp->bio2.bi_end_io = bio_pair_end_2;