Revert "netlink: netlink_recvmsg() fix"

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>

1 files changed, 6 insertions, 16 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 2cbf380377d5..8648a9922aab 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -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)