cfg80211: add netlink channel put helper

This adds a netlink channel put helper, nl80211_msg_put_channel(),
which we will also make use of later for the beacon hints events.
Acked-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NLuis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

net/wireless/nl80211.c

@@ -156,6 +156,30 @@ static inline void *nl80211hdr_put(struct sk_buff *skb, u32 pid, u32 seq,
 	return genlmsg_put(skb, pid, seq, &nl80211_fam, flags, cmd);
 }
 
+static int nl80211_msg_put_channel(struct sk_buff *msg,
+				   struct ieee80211_channel *chan)
+{
+	NLA_PUT_U32(msg, NL80211_FREQUENCY_ATTR_FREQ,
+		    chan->center_freq);
+
+	if (chan->flags & IEEE80211_CHAN_DISABLED)
+		NLA_PUT_FLAG(msg, NL80211_FREQUENCY_ATTR_DISABLED);
+	if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
+		NLA_PUT_FLAG(msg, NL80211_FREQUENCY_ATTR_PASSIVE_SCAN);
+	if (chan->flags & IEEE80211_CHAN_NO_IBSS)
+		NLA_PUT_FLAG(msg, NL80211_FREQUENCY_ATTR_NO_IBSS);
+	if (chan->flags & IEEE80211_CHAN_RADAR)
+		NLA_PUT_FLAG(msg, NL80211_FREQUENCY_ATTR_RADAR);
+
+	NLA_PUT_U32(msg, NL80211_FREQUENCY_ATTR_MAX_TX_POWER,
+		    DBM_TO_MBM(chan->max_power));
+
+	return 0;
+
+ nla_put_failure:
+	return -ENOBUFS;
+}
+
 /* netlink command implementations */
 
 static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
@@ -234,20 +258,9 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
 				goto nla_put_failure;
 
 			chan = &dev->wiphy.bands[band]->channels[i];
-			NLA_PUT_U32(msg, NL80211_FREQUENCY_ATTR_FREQ,
-				    chan->center_freq);
-
-			if (chan->flags & IEEE80211_CHAN_DISABLED)
-				NLA_PUT_FLAG(msg, NL80211_FREQUENCY_ATTR_DISABLED);
-			if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
-				NLA_PUT_FLAG(msg, NL80211_FREQUENCY_ATTR_PASSIVE_SCAN);
-			if (chan->flags & IEEE80211_CHAN_NO_IBSS)
-				NLA_PUT_FLAG(msg, NL80211_FREQUENCY_ATTR_NO_IBSS);
-			if (chan->flags & IEEE80211_CHAN_RADAR)
-				NLA_PUT_FLAG(msg, NL80211_FREQUENCY_ATTR_RADAR);
-
-			NLA_PUT_U32(msg, NL80211_FREQUENCY_ATTR_MAX_TX_POWER,
-				    DBM_TO_MBM(chan->max_power));
+
+			if (nl80211_msg_put_channel(msg, chan))
+				goto nla_put_failure;
 
 			nla_nest_end(msg, nl_freq);
 		}