From: Mike Snitzer <snitzer@redhat.com>
Date: Fri, 4 Dec 2020 22:21:03 +0000 (-0500)
Subject: block: fix incorrect branching in blk_max_size_offset()
X-Git-Tag: baikal/aarch64/sdk6.1~7800^2
X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=527c95e306f36d11bf2bd73b1008e9449fb90741;p=kernel.git

block: fix incorrect branching in blk_max_size_offset()

If non-zero 'chunk_sectors' is passed in to blk_max_size_offset() that
override will be incorrectly ignored.

Old blk_max_size_offset() branching, prior to commit 32c714605572,
must be used only if passed 'chunk_sectors' override is zero.

Fixes: 32c714605572 ("dm: fix IO splitting")
Cc: stable@vger.kernel.org # 5.9
Reported-by: John Dorminy <jdorminy@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 24ae504cf77dd..033eb5f73b654 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1076,10 +1076,12 @@ static inline unsigned int blk_max_size_offset(struct request_queue *q,
 					       sector_t offset,
 					       unsigned int chunk_sectors)
 {
-	if (!chunk_sectors && q->limits.chunk_sectors)
-		chunk_sectors = q->limits.chunk_sectors;
-	else
-		return q->limits.max_sectors;
+	if (!chunk_sectors) {
+		if (q->limits.chunk_sectors)
+			chunk_sectors = q->limits.chunk_sectors;
+		else
+			return q->limits.max_sectors;
+	}
 
 	if (likely(is_power_of_2(chunk_sectors)))
 		chunk_sectors -= offset & (chunk_sectors - 1);