net-timestamp: Make the clone operation stand-alone from phy timestamping

The phy timestamping takes a different path than the regular timestamping
does in that it will create a clone first so that the packets needing to be
timestamped can be placed in a queue, or the context block could be used.

In order to support these use cases I am pulling the core of the code out
so it can be used in other drivers beyond just phy devices.

In addition I have added a destructor named sock_efree which is meant to
provide a simple way for dropping the reference to skb exceptions that
aren't part of either the receive or send windows for the socket, and I
have removed some duplication in spots where this destructor could be used
in place of sock_edemux.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 11 deletions

diff --git a/net/core/timestamping.c b/net/core/timestamping.c
index f48a59fd8f39..43d3dd62fcc8 100644
--- a/net/core/timestamping.c
+++ b/net/core/timestamping.c
@@ -36,10 +36,9 @@ void skb_clone_tx_timestamp(struct sk_buff *skb)
 {
         struct phy_device *phydev;
         struct sk_buff *clone;
-        struct sock *sk = skb->sk;
         unsigned int type;
 
-        if (!sk)
+        if (!skb->sk)
                 return;
 
         type = classify(skb);
@@ -48,16 +47,9 @@ void skb_clone_tx_timestamp(struct sk_buff *skb)
 
         phydev = skb->dev->phydev;
         if (likely(phydev->drv->txtstamp)) {
-                if (!atomic_inc_not_zero(&sk->sk_refcnt))
+                clone = skb_clone_sk(skb);
+                if (!clone)
                         return;
-
-                clone = skb_clone(skb, GFP_ATOMIC);
-                if (!clone) {
-                        sock_put(sk);
-                        return;
-                }
-
-                clone->sk = sk;
                 phydev->drv->txtstamp(phydev, clone, type);
         }
 }