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>

9 files changed, 31 insertions, 19 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 3896de7..65f01f7 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1714,7 +1714,8 @@ static int neightbl_fill_parms(struct sk_buff *skb, struct neigh_parms *parms)
 	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,
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index cf857c4..a9a7721 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -498,7 +498,8 @@ int rtnetlink_put_metrics(struct sk_buff *skb, u32 *metrics)
 	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,
diff --git a/net/netlink/attr.c b/net/netlink/attr.c
index feb326f..47bbf45 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 d16929c..f5aa23c 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)
diff --git a/net/sched/sch_dsmark.c b/net/sched/sch_dsmark.c
index 0df911f..64465ba 100644
--- a/net/sched/sch_dsmark.c
+++ b/net/sched/sch_dsmark.c
@@ -444,7 +444,8 @@ static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
 	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)
@@ -466,7 +467,8 @@ 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 = {
diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c
index 3a9d226..c89fba5 100644
--- a/net/sched/sch_gred.c
+++ b/net/sched/sch_gred.c
@@ -582,7 +582,8 @@ append_opt:
 	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)
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 87293d0..fdfaa3f 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1360,7 +1360,7 @@ hfsc_dump_class(struct Qdisc *sch, unsigned long arg, struct sk_buff *skb,
 
  nla_put_failure:
 	nla_nest_cancel(skb, nest);
-	return -1;
+	return -EMSGSIZE;
 }
 
 static int
diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
index 3dcd493..5c56985 100644
--- a/net/sched/sch_red.c
+++ b/net/sched/sch_red.c
@@ -281,7 +281,8 @@ static int red_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 int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 2bdd4dd..fb75f26 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -187,7 +187,8 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
 	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)
@@ -273,7 +274,8 @@ static int nl80211_send_iface(struct sk_buff *msg, u32 pid, u32 seq, int flags,
 	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)
@@ -928,7 +930,8 @@ static int nl80211_send_station(struct sk_buff *msg, u32 pid, u32 seq,
 	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,
@@ -1267,7 +1270,8 @@ static int nl80211_send_mpath(struct sk_buff *msg, u32 pid, u32 seq,
 	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,