include/net/genetlink.h: Allow genlmsg_cancel to accept a NULL argument

nlmsg_cancel can accept NULL as its second argument, so for similarity,
this patch extends genlmsg_cancel to be able to accept a NULL second
argument as well.

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index 8a64b811a39a..b4c7c1cbcf40 100644
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -195,7 +195,8 @@ static inline int genlmsg_end(struct sk_buff *skb, void *hdr)
  */
 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
 {
-        nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
+        if (hdr)
+                nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
 }
 
 /**