[PATCH 4/4] drbd: Add check for error pointer

[Ethan Tidmore]

The function find_cfg_context_attr() can return an error pointer or NULL
in its error path.

Change NULL check to IS_ERR_OR_NULL().

Detected by Smatch:
drivers/block/drbd/drbd_nl.c:6571 drbd_adm_dump_paths() error:
'resource_filter' dereferencing possible ERR_PTR()

Fixes: 626c95b0e2a23 ("drbd: rework netlink interface for DRBD 9 multi-peer config")
Signed-off-by: Ethan Tidmore <ethantidmore06 at gmail.com>
---
 drivers/block/drbd/drbd_nl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index c5e253820ccf..1f458eb972e9 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -6566,7 +6566,7 @@ static int drbd_adm_dump_paths(struct sk_buff *skb, struct netlink_callback *cb)
 	resource = (struct drbd_resource *)cb->args[0];
 	if (!cb->args[0]) {
 		resource_filter = find_cfg_context_attr(cb->nlh, T_ctx_resource_name);
-		if (resource_filter) {
+		if (!IS_ERR_OR_NULL(resource_filter)) {
 			retcode = ERR_RES_NOT_KNOWN;
 			resource = drbd_find_resource(nla_data(resource_filter));
 			if (!resource)
-- 
2.53.0