From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shaohua Li Subject: [patch 1/7 v2] block: makes bio_split support bio without data Date: Fri, 10 Aug 2012 10:51:14 +0800 Message-ID: <20120810025206.336740696@kernel.org> References: <20120810025113.050392766@kernel.org> Return-path: Content-Disposition: inline; filename=bio_split-fix.patch Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org Cc: neilb@suse.de, axboe@kernel.dk, shli@kernel.org List-Id: linux-raid.ids discard bio hasn't data attached. We hit a BUG_ON with such bio. This makes bio_split works for such bio. Signed-off-by: Shaohua Li --- fs/bio.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) Index: linux/fs/bio.c =================================================================== --- linux.orig/fs/bio.c 2012-06-01 10:10:31.626395215 +0800 +++ linux/fs/bio.c 2012-06-04 16:45:17.175941457 +0800 @@ -1500,7 +1500,7 @@ struct bio_pair *bio_split(struct bio *b 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; @@ -1510,17 +1510,19 @@ struct bio_pair *bio_split(struct bio *b 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]; - bp->bv2.bv_offset += first_sectors << 9; - bp->bv2.bv_len -= first_sectors << 9; - bp->bv1.bv_len = first_sectors << 9; + if (bi->bi_vcnt != 0) { + bp->bv1 = bi->bi_io_vec[0]; + bp->bv2 = bi->bi_io_vec[0]; + 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;