[PATCH] badblocks: Fix a nonsense WARN_ON() which checks whether a u64 variable < 0

[colyli@kernel.org]

From: Coly Li <colyli@kernel.org>

In _badblocks_check(), there are lines of code like this,
1246         sectors -= len;
[snipped]
1251         WARN_ON(sectors < 0);

The WARN_ON() at line 1257 doesn't make sense because sectors is
unsigned long long type and never to be <0.

Fix it by checking directly checking whether sectors is less than len.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Coly Li <colyli@kernel.org>
---
 block/badblocks.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/badblocks.c b/block/badblocks.c
index 673ef068423a..ece64e76fe8f 100644
--- a/block/badblocks.c
+++ b/block/badblocks.c
@@ -1242,14 +1242,15 @@ static int _badblocks_check(struct badblocks *bb, sector_t s, sector_t sectors,
 	len = sectors;
 
 update_sectors:
+	/* This situation should never happen */
+	WARN_ON(sectors < len);
+
 	s += len;
 	sectors -= len;
 
 	if (sectors > 0)
 		goto re_check;
 
-	WARN_ON(sectors < 0);
-
 	if (unacked_badblocks > 0)
 		rv = -1;
 	else if (acked_badblocks > 0)
-- 
2.47.2