skb: Add documentation for skb_clone_sk

This change adds some documentation to the call skb_clone_sk.  This is
meant to help clarify the purpose of the function for other developers.

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

1 files changed, 13 insertions, 0 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index a18dfb02d944..c9da77a95e2d 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3511,6 +3511,19 @@ struct sk_buff *sock_dequeue_err_skb(struct sock *sk)
 }
 EXPORT_SYMBOL(sock_dequeue_err_skb);
 
+/**
+ * skb_clone_sk - create clone of skb, and take reference to socket
+ * @skb: the skb to clone
+ *
+ * This function creates a clone of a buffer that holds a reference on
+ * sk_refcnt.  Buffers created via this function are meant to be
+ * returned using sock_queue_err_skb, or free via kfree_skb.
+ *
+ * When passing buffers allocated with this function to sock_queue_err_skb
+ * it is necessary to wrap the call with sock_hold/sock_put in order to
+ * prevent the socket from being released prior to being enqueued on
+ * the sk_error_queue.
+ */
 struct sk_buff *skb_clone_sk(struct sk_buff *skb)
 {
         struct sock *sk = skb->sk;