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 <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/genetlink.h

···
  * @skb: socket buffer the message is stored in
  * @hdr: generic netlink message header
  */
-static inline int genlmsg_cancel(struct sk_buff *skb, void *hdr)
+static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
 {
-	return nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
+	nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
 }
 
 /**

include/net/netlink.h

···
  * @skb: socket buffer the message is stored in
  * @mark: mark to trim to
  *
- * Trims the message to the provided mark. Returns -1.
+ * Trims the message to the provided mark.
  */
-static inline int nlmsg_trim(struct sk_buff *skb, const void *mark)
+static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
 {
 	if (mark)
 		skb_trim(skb, (unsigned char *) mark - skb->data);
-
-	return -1;
 }
 
 /**
···
  * @nlh: netlink message header
  *
  * Removes the complete netlink message including all
- * attributes from the socket buffer again. Returns -1.
+ * attributes from the socket buffer again.
  */
-static inline int nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
+static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
-	return nlmsg_trim(skb, nlh);
+	nlmsg_trim(skb, nlh);
 }
 
 /**
···
 	int nested_len = nla_len(nla) - NLA_ALIGN(len);
 
 	if (nested_len < 0)
-		return -1;
+		return -EINVAL;
 	if (nested_len >= nla_attr_size(0))
 		return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len),
 				 nested_len, policy);
···
  * @start: container attribute
  *
  * Removes the container attribute and including all nested
- * attributes. Returns -1.
+ * attributes. Returns -EMSGSIZE
  */
-static inline int nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
+static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
 {
-	return nlmsg_trim(skb, start);
+	nlmsg_trim(skb, start);
 }
 
 /**

net/core/neighbour.c

···
 	return nla_nest_end(skb, nest);
 
 nla_put_failure:
-	return nla_nest_cancel(skb, nest);
+	nla_nest_cancel(skb, nest);
+	return -EMSGSIZE;
 }
 
 static int neightbl_fill_info(struct sk_buff *skb, struct neigh_table *tbl,

net/core/rtnetlink.c

···
 	return nla_nest_end(skb, mx);
 
 nla_put_failure:
-	return nla_nest_cancel(skb, mx);
+	nla_nest_cancel(skb, mx);
+	return -EMSGSIZE;
 }
 
 int rtnl_put_cacheinfo(struct sk_buff *skb, struct dst_entry *dst, u32 id,

net/netlink/attr.c

···
  * @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;
···
  * @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;
···
  * @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;

net/netlink/genetlink.c

···
 	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,
···
 	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)

net/sched/sch_dsmark.c

···
 	return nla_nest_end(skb, opts);
 
 nla_put_failure:
-	return nla_nest_cancel(skb, opts);
+	nla_nest_cancel(skb, opts);
+	return -EMSGSIZE;
 }
 
 static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
···
 	return nla_nest_end(skb, opts);
 
 nla_put_failure:
-	return nla_nest_cancel(skb, opts);
+	nla_nest_cancel(skb, opts);
+	return -EMSGSIZE;
 }
 
 static const struct Qdisc_class_ops dsmark_class_ops = {

net/sched/sch_gred.c

···
 	return nla_nest_end(skb, opts);
 
 nla_put_failure:
-	return nla_nest_cancel(skb, opts);
+	nla_nest_cancel(skb, opts);
+	return -EMSGSIZE;
 }
 
 static void gred_destroy(struct Qdisc *sch)

net/sched/sch_hfsc.c

···
 
  nla_put_failure:
 	nla_nest_cancel(skb, nest);
-	return -1;
+	return -EMSGSIZE;
 }
 
 static int

net/sched/sch_red.c

···
 	return nla_nest_end(skb, opts);
 
 nla_put_failure:
-	return nla_nest_cancel(skb, opts);
+	nla_nest_cancel(skb, opts);
+	return -EMSGSIZE;
 }
 
 static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)

net/wireless/nl80211.c

···
 	return genlmsg_end(msg, hdr);
 
  nla_put_failure:
-	return genlmsg_cancel(msg, hdr);
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
 }
 
 static int nl80211_dump_wiphy(struct sk_buff *skb, struct netlink_callback *cb)
···
 	return genlmsg_end(msg, hdr);
 
  nla_put_failure:
-	return genlmsg_cancel(msg, hdr);
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
 }
 
 static int nl80211_dump_interface(struct sk_buff *skb, struct netlink_callback *cb)
···
 	return genlmsg_end(msg, hdr);
 
  nla_put_failure:
-	return genlmsg_cancel(msg, hdr);
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
 }
 
 static int nl80211_dump_station(struct sk_buff *skb,
···
 	return genlmsg_end(msg, hdr);
 
  nla_put_failure:
-	return genlmsg_cancel(msg, hdr);
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
 }
 
 static int nl80211_dump_mpath(struct sk_buff *skb,