[PATCH] loop: fix passing zero to 'PTR_ERR' warning

[Ding Xiang <dingxiang@xxxxxxxxxxxxxxxxxxxx>]

Fix a static code checker warning:
    drivers/block/loop.c:798 loop_attr_backing_file_show()
    warn: passing zero to 'PTR_ERR'

Signed-off-by: Ding Xiang <dingxiang@xxxxxxxxxxxxxxxxxxxx>
---
 drivers/block/loop.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 475e1a7..bcada87 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -795,7 +795,7 @@ static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf)
 	spin_unlock_irq(&lo->lo_lock);
 
 	if (IS_ERR_OR_NULL(p))
-		ret = PTR_ERR(p);
+		ret = PTR_ERR_OR_ZERO(p);
 	else {
 		ret = strlen(p);
 		memmove(buf, p, ret);
-- 
2.7.4