From: Christoph Hellwig <hch@lst.de>
Date: Mon, 12 Aug 2019 17:39:56 +0200
Subject: [PATCH] block: improve the gap check in __bio_add_pc_page
References: bsc#1156419,jsc#SLE-8281
Git-commit: 320ea869a12cec206756207c6ca5f817ec45c7f2
Patch-mainline: v5.4-rc1
If we can add more data into an existing segment we do not create a gap
per definition, so move the check for a gap after the attempt to merge
into the segment.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
block/bio.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index da7545382881..b699098d54f3 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -710,18 +710,18 @@ static int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
goto done;
}
- /*
- * If the queue doesn't support SG gaps and adding this
- * offset would create a gap, disallow it.
- */
- if (bvec_gap_to_prev(q, bvec, offset))
- return 0;
-
if (page_is_mergeable(bvec, page, len, offset, &same_page) &&
can_add_page_to_seg(q, bvec, page, len, offset)) {
bvec->bv_len += len;
goto done;
}
+
+ /*
+ * If the queue doesn't support SG gaps and adding this segment
+ * would create a gap, disallow it.
+ */
+ if (bvec_gap_to_prev(q, bvec, offset))
+ return 0;
}
if (bio_full(bio, len))
--
2.16.4