From bc9e9cf0401f18e33b78d4c8a518661b8346baf7 Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@redhat.com>
Date: Fri, 10 Aug 2018 11:23:56 -0400
Subject: [PATCH] dm crypt: don't decrease device limits
Git-commit: bc9e9cf0401f18e33b78d4c8a518661b8346baf7
References: bsc#1111974
Patch-mainline: v4.19-rc1

dm-crypt should only increase device limits, it should not decrease them.

This fixes a bug where the user could creates a crypt device with 1024
sector size on the top of scsi device that had 4096 logical block size.
The limit 4096 would be lost and the user could incorrectly send
1024-I/Os to the crypt device.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Coly Li <colyli@suse.de>

---
 drivers/md/dm-crypt.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index d412bd4b911c..f266c81f396f 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -3061,11 +3061,11 @@ static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits)
 	 */
 	limits->max_segment_size = PAGE_SIZE;
 
-	if (cc->sector_size != (1 << SECTOR_SHIFT)) {
-		limits->logical_block_size = cc->sector_size;
-		limits->physical_block_size = cc->sector_size;
-		blk_limits_io_min(limits, cc->sector_size);
-	}
+	limits->logical_block_size =
+		max_t(unsigned short, limits->logical_block_size, cc->sector_size);
+	limits->physical_block_size =
+		max_t(unsigned, limits->physical_block_size, cc->sector_size);
+	limits->io_min = max_t(unsigned, limits->io_min, cc->sector_size);
 }
 
 static struct target_type crypt_target = {
-- 
2.19.0