net: skb_segment() provides list head and tail
Its unfortunate we have to walk again skb list to find the tail
after segmentation, even if data is probably hot in cpu caches.
skb_segment() can store the tail of the list into segs->prev,
and validate_xmit_skb_list() can immediately get the tail.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 9a423e2..7b3df0d 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3083,6 +3083,11 @@
}
} while ((offset += len) < head_skb->len);
+ /* Some callers want to get the end of the list.
+ * Put it in segs->prev to avoid walking the list.
+ * (see validate_xmit_skb_list() for example)
+ */
+ segs->prev = tail;
return segs;
err: