netlink: Improve returned error codes

Make nlmsg_trim(), nlmsg_cancel(), genlmsg_cancel(), and
nla_nest_cancel() void functions.

Return -EMSGSIZE instead of -1 if the provided message buffer is not
big enough.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 10 insertions, 8 deletions

diff --git a/net/netlink/attr.c b/net/netlink/attr.c
index feb326f4a752..47bbf45ae5d7 100644
--- a/net/netlink/attr.c
+++ b/net/netlink/attr.c
@@ -400,13 +400,13 @@ void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
  * @attrlen: length of attribute payload
  * @data: head of attribute payload
  *
- * Returns -1 if the tailroom of the skb is insufficient to store
+ * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
  * the attribute header and payload.
  */
 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
 {
         if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
-                return -1;
+                return -EMSGSIZE;
 
         __nla_put(skb, attrtype, attrlen, data);
         return 0;
@@ -418,13 +418,13 @@ int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
  * @attrlen: length of attribute payload
  * @data: head of attribute payload
  *
- * Returns -1 if the tailroom of the skb is insufficient to store
+ * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
  * the attribute payload.
  */
 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
 {
         if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
-                return -1;
+                return -EMSGSIZE;
 
         __nla_put_nohdr(skb, attrlen, data);
         return 0;
@@ -436,13 +436,13 @@ int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
  * @attrlen: length of attribute payload
  * @data: head of attribute payload
  *
- * Returns -1 if the tailroom of the skb is insufficient to store
+ * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
  * the attribute payload.
  */
 int nla_append(struct sk_buff *skb, int attrlen, const void *data)
 {
         if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
-                return -1;
+                return -EMSGSIZE;
 
         memcpy(skb_put(skb, attrlen), data, attrlen);
         return 0;
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index d16929c9b4bc..f5aa23c3e886 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -554,7 +554,8 @@ static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
         return genlmsg_end(skb, hdr);
 
 nla_put_failure:
-        return genlmsg_cancel(skb, hdr);
+        genlmsg_cancel(skb, hdr);
+        return -EMSGSIZE;
 }
 
 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
@@ -590,7 +591,8 @@ static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
         return genlmsg_end(skb, hdr);
 
 nla_put_failure:
-        return genlmsg_cancel(skb, hdr);
+        genlmsg_cancel(skb, hdr);
+        return -EMSGSIZE;
 }
 
 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)