Merge branch 'dropcount'

Eyal Birger says:

====================
net: move skb->dropcount to skb->cb[]

Commit 977750076d98 ("af_packet: add interframe drop cmsg (v6)")
unionized skb->mark and skb->dropcount in order to allow recording
of the socket drop count while maintaining struct sk_buff size.

skb->dropcount was introduced since there was no available room
in skb->cb[] in packet sockets. However, its introduction led to
the inability to export skb->mark to userspace.

It was considered to alias skb->priority instead of skb->mark.
However, that would lead to the inabilty to export skb->priority
to userspace if desired. Such change may also lead to hard-to-find
issues as skb->priority is assumed to be alias free, and, as noted
by Shmulik Ladkani, is not 'naturally orthogonal' with other skb
fields.

This patch series follows the suggestions made by Eric Dumazet moving
the dropcount metric to skb->cb[], eliminating this problem
at the expense of 4 bytes less in skb->cb[] for protocol families
using it.

The patch series include compactization of bluetooth and packet
use of skb->cb[] as well as the infrastructure for placing dropcount
in skb->cb[].
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 2 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 9d72a0fcd928..4b57ea8dabc7 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3005,12 +3005,11 @@ static void __init tcp_init_mem(void)
 
 void __init tcp_init(void)
 {
-	struct sk_buff *skb = NULL;
 	unsigned long limit;
 	int max_rshare, max_wshare, cnt;
 	unsigned int i;
 
-	BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
+	sock_skb_cb_check_size(sizeof(struct tcp_skb_cb));
 
 	percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
 	percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);