From: Christoph Hellwig <hch@lst.de>
Date: Wed, 3 Jul 2019 12:24:35 +0000 (-0700)
Subject: block: nr_phys_segments needs to be zero for REQ_OP_WRITE_ZEROES
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=d665e12aa713e598a1100a320e5679c3f73823ed;p=openwrt%2Fstaging%2Fblogic.git

block: nr_phys_segments needs to be zero for REQ_OP_WRITE_ZEROES

Fix a regression introduced when removing bi_phys_segments for Write Zeroes
requests, which need to have a segment count of zero, as they don't have a
payload.

Fixes: 14ccb66b3f58 ("block: remove the bi_phys_segments field in struct bio")
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/block/blk-merge.c b/block/blk-merge.c
index ca45eb51c669..57f7990b342d 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -105,7 +105,7 @@ static struct bio *blk_bio_discard_split(struct request_queue *q,
 static struct bio *blk_bio_write_zeroes_split(struct request_queue *q,
 		struct bio *bio, struct bio_set *bs, unsigned *nsegs)
 {
-	*nsegs = 1;
+	*nsegs = 0;
 
 	if (!q->limits.max_write_zeroes_sectors)
 		return NULL;