[MAC80211]: add interface index to key debugfs

Add a new file 'ifindex' to each key's debugfs dir to
allow finding which interface the key was configured on.
This isn't done as a symlink because of possible netdev
name changes.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mac80211/debugfs_key.c b/net/mac80211/debugfs_key.c
index 36e7812..8e4a1bc 100644
--- a/net/mac80211/debugfs_key.c
+++ b/net/mac80211/debugfs_key.c
@@ -56,6 +56,8 @@
 KEY_CONF_FILE(hw_key_idx, D);
 KEY_FILE(flags, X);
 KEY_FILE(tx_rx_count, D);
+KEY_READ(ifindex, sdata->dev->ifindex, 20, "%d\n");
+KEY_OPS(ifindex);
 
 static ssize_t key_algorithm_read(struct file *file,
 				  char __user *userbuf,
@@ -209,6 +211,7 @@
 	DEBUGFS_ADD(rx_spec);
 	DEBUGFS_ADD(replays);
 	DEBUGFS_ADD(key);
+	DEBUGFS_ADD(ifindex);
 };
 
 #define DEBUGFS_DEL(name) \
@@ -229,6 +232,7 @@
 	DEBUGFS_DEL(rx_spec);
 	DEBUGFS_DEL(replays);
 	DEBUGFS_DEL(key);
+	DEBUGFS_DEL(ifindex);
 
 	debugfs_remove(key->debugfs.stalink);
 	key->debugfs.stalink = NULL;
diff --git a/net/mac80211/ieee80211_key.h b/net/mac80211/ieee80211_key.h
index a4e5fbb..ae49418 100644
--- a/net/mac80211/ieee80211_key.h
+++ b/net/mac80211/ieee80211_key.h
@@ -101,6 +101,7 @@
 		struct dentry *rx_spec;
 		struct dentry *replays;
 		struct dentry *key;
+		struct dentry *ifindex;
 	} debugfs;
 #endif