mac80211: skip unnecessary pskb_expand_head calls

If the skb is not cloned and we don't need any extra headroom, there
is no point in reallocating the skb head.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 8d01d21dff1e..90ee23550033 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1546,8 +1546,10 @@ static int ieee80211_skb_resize(struct ieee80211_local *local,
 
         if (skb_header_cloned(skb))
                 I802_DEBUG_INC(local->tx_expand_skb_head_cloned);
-        else
+        else if (head_need || tail_need)
                 I802_DEBUG_INC(local->tx_expand_skb_head);
+        else
+                return 0;
 
         if (pskb_expand_head(skb, head_need, tail_need, GFP_ATOMIC)) {
                 wiphy_debug(local->hw.wiphy,