[PATCH 04/11] netlink: add netlink_skb_set_owner_r()
From: Patrick McHardy <hidden>
Date: 2012-08-20 06:18:45
Also in:
netfilter-devel
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
For mmap'ed I/O a netlink specific skb destructor needs to be invoked after the final kfree_skb() to clean up state. This doesn't work currently since the skb's ownership is transfered to the receiving socket using skb_set_owner_r(), which orphans the skb, thereby invoking the destructor prematurely. Since netlink doesn't account skbs to the originating socket, there's no need to orphan the skb. Add a netlink specific skb_set_owner_r() variant that does not orphan the skb and use a netlink specific destructor to call sock_rfree(). Signed-off-by: Patrick McHardy <redacted> --- net/netlink/af_netlink.c | 18 ++++++++++++++++-- 1 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 3233601..e2d0177 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c@@ -166,6 +166,20 @@ static void netlink_consume_callback(struct netlink_callback *cb) kfree(cb); } +static void netlink_skb_destructor(struct sk_buff *skb) +{ + sock_rfree(skb); +} + +static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk) +{ + WARN_ON(skb->sk != NULL); + skb->sk = sk; + skb->destructor = netlink_skb_destructor; + atomic_add(skb->truesize, &sk->sk_rmem_alloc); + sk_mem_charge(sk, skb->truesize); +} + static void netlink_sock_destruct(struct sock *sk) { struct netlink_sock *nlk = nlk_sk(sk);
@@ -855,7 +869,7 @@ int netlink_attachskb(struct sock *sk, struct sk_buff *skb, } return 1; } - skb_set_owner_r(skb, sk); + netlink_skb_set_owner_r(skb, sk); return 0; }
@@ -924,7 +938,7 @@ static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb) ret = -ECONNREFUSED; if (nlk->netlink_rcv != NULL) { ret = skb->len; - skb_set_owner_r(skb, sk); + netlink_skb_set_owner_r(skb, sk); nlk->netlink_rcv(skb); consume_skb(skb); } else {
--
1.7.7.6