1 files changed, 36 insertions, 0 deletions

diff --git a/net/core/datagram.c b/net/core/datagram.c
index 1bcfef51ac58..f8d322e1ea92 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -47,6 +47,7 @@
 #include <linux/rtnetlink.h>
 #include <linux/poll.h>
 #include <linux/highmem.h>
+#include <linux/spinlock.h>
 
 #include <net/protocol.h>
 #include <linux/skbuff.h>
@@ -200,6 +201,41 @@ void skb_free_datagram(struct sock *sk, struct sk_buff *skb)
 }
 
 /**
+ *      skb_kill_datagram - Free a datagram skbuff forcibly
+ *      @sk: socket
+ *      @skb: datagram skbuff
+ *      @flags: MSG_ flags
+ *
+ *      This function frees a datagram skbuff that was received by
+ *      skb_recv_datagram.  The flags argument must match the one
+ *      used for skb_recv_datagram.
+ *
+ *      If the MSG_PEEK flag is set, and the packet is still on the
+ *      receive queue of the socket, it will be taken off the queue
+ *      before it is freed.
+ *
+ *      This function currently only disables BH when acquiring the
+ *      sk_receive_queue lock.  Therefore it must not be used in a
+ *      context where that lock is acquired in an IRQ context.
+ */
+
+void skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags)
+{
+        if (flags & MSG_PEEK) {
+                spin_lock_bh(&sk->sk_receive_queue.lock);
+                if (skb == skb_peek(&sk->sk_receive_queue)) {
+                        __skb_unlink(skb, &sk->sk_receive_queue);
+                        atomic_dec(&skb->users);
+                }
+                spin_unlock_bh(&sk->sk_receive_queue.lock);
+        }
+
+        kfree_skb(skb);
+}
+
+EXPORT_SYMBOL(skb_kill_datagram);
+
+/**
  *      skb_copy_datagram_iovec - Copy a datagram to an iovec.
  *      @skb: buffer to copy
  *      @offset: offset in the buffer to start copying from