From: Arnd Bergmann <arnd@xxxxxxxx>
The -Wrestrict warning (disabled by default) points out undefined
behavior calling snprintf():
drivers/block/rnbd/rnbd-clt-sysfs.c: In function 'rnbd_clt_get_path_name':
drivers/block/rnbd/rnbd-clt-sysfs.c:486:8: error: 'snprintf' argument 4 overlaps destination object 'buf' [-Werror=restrict]
486 | ret = snprintf(buf, len, "%s@%s", buf, dev->sess->sessname);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/block/rnbd/rnbd-clt-sysfs.c:472:67: note: destination object referenced by 'restrict'-qualified argument 1 was declared here
472 | static int rnbd_clt_get_path_name(struct rnbd_clt_dev *dev, char *buf,
| ~~~~~~^~~
This can be simplified by using a single snprintf() to print the
whole buffer, avoiding the undefined behavior.
Fixes: 91f4acb2801c ("block/rnbd-clt: support mapping two devices with the same name from different servers")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/block/rnbd/rnbd-clt-sysfs.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/drivers/block/rnbd/rnbd-clt-sysfs.c b/drivers/block/rnbd/rnbd-clt-sysfs.c
index d4aa6bfc9555..38251b749664 100644
--- a/drivers/block/rnbd/rnbd-clt-sysfs.c
+++ b/drivers/block/rnbd/rnbd-clt-sysfs.c
@@ -479,11 +479,7 @@ static int rnbd_clt_get_path_name(struct rnbd_clt_dev *dev, char *buf,
while ((s = strchr(pathname, '/')))
s[0] = '!';
- ret = snprintf(buf, len, "%s", pathname);
- if (ret >= len)
- return -ENAMETOOLONG;
-
- ret = snprintf(buf, len, "%s@%s", buf, dev->sess->sessname);
+ ret = snprintf(buf, len, "%s@%s", pathname, dev->sess->sessname);
if (ret >= len)
return -ENAMETOOLONG;
--
2.29.2
