batman-adv: avoid skb_linearise() if not needed

Whenever we want to access headers only, we do not need to linearise the whole
packet. Instead we can use pskb_may_pull()

Signed-off-by: Antonio Quartulli <ordex@autistici.org>

diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 7ed9d8f..4c6467d 100644 (file)
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -916,8 +916,9 @@ static int check_unicast_ttvn(struct bat_priv *bat_priv,
 
        /* Check whether I have to reroute the packet */
        if (seq_before(unicast_packet->ttvn, curr_ttvn) || tt_poss_change) {
-               /* Linearize the skb before accessing it */
-               if (skb_linearize(skb) < 0)
+               /* check if there is enough data before accessing it */
+               if (pskb_may_pull(skb, sizeof(struct unicast_packet) +
+                                 ETH_HLEN) < 0)
                        return 0;
 
                ethhdr = (struct ethhdr *)(skb->data +