Revert "netlink: netlink_recvmsg() fix"
David S. Miller [Mon, 16 Aug 2010 06:21:50 +0000 (23:21 -0700)]
This reverts commit 1235f504aaba2ebeabc863fdb3ceac764a317d47.

It causes regressions worse than the problem it was trying
to fix.  Eric will try to solve the problem another way.

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

net/netlink/af_netlink.c

index 2cbf380..8648a99 100644 (file)
@@ -1406,7 +1406,7 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
        struct netlink_sock *nlk = nlk_sk(sk);
        int noblock = flags&MSG_DONTWAIT;
        size_t copied;
-       struct sk_buff *skb;
+       struct sk_buff *skb, *frag __maybe_unused = NULL;
        int err;
 
        if (flags&MSG_OOB)
@@ -1441,21 +1441,7 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
                        kfree_skb(skb);
                        skb = compskb;
                } else {
-                       /*
-                        * Before setting frag_list to NULL, we must get a
-                        * private copy of skb if shared (because of MSG_PEEK)
-                        */
-                       if (skb_shared(skb)) {
-                               struct sk_buff *nskb;
-
-                               nskb = pskb_copy(skb, GFP_KERNEL);
-                               kfree_skb(skb);
-                               skb = nskb;
-                               err = -ENOMEM;
-                               if (!skb)
-                                       goto out;
-                       }
-                       kfree_skb(skb_shinfo(skb)->frag_list);
+                       frag = skb_shinfo(skb)->frag_list;
                        skb_shinfo(skb)->frag_list = NULL;
                }
        }
@@ -1492,6 +1478,10 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
        if (flags & MSG_TRUNC)
                copied = skb->len;
 
+#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
+       skb_shinfo(skb)->frag_list = frag;
+#endif
+
        skb_free_datagram(sk, skb);
 
        if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)