6lowpan: Use skb_cow in IPHC decompression.
Currently there are potentially 2 skb_copy_expand calls in IPHC
decompression. This patch replaces this with one call to
skb_cow which will check to see if there is enough headroom
first to ensure it's only done if necessary and will handle
alignment issues for cache.
As skb_cow uses pskb_expand_head we ensure the skb isn't shared from
bluetooth and ieee802.15.4 code that use the IPHC decompression.
Signed-off-by: Martin Townsend <martin.townsend@xsilon.com>
Acked-by: Alexander Aring <alex.aring@gmail.com>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 9b5c89b..6c5c2ef 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -309,6 +309,10 @@
if (dev->type != ARPHRD_6LOWPAN)
goto drop;
+ skb = skb_share_check(skb, GFP_ATOMIC);
+ if (!skb)
+ goto drop;
+
/* check that it's our buffer */
if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
/* Copy the packet so that the IPv6 header is