net: Add and use skb_copy_datagram_msg() helper.

This encapsulates all of the skb_copy_datagram_iovec() callers
with call argument signature "skb, offset, msghdr->msg_iov, length".

When we move to iov_iters in the networking, the iov_iter object will
sit in the msghdr.

Having a helper like this means there will be less places to touch
during that transformation.

Based upon descriptions and patch from Al Viro.

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

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 74ed34413969..39ec7530ae27 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -21,6 +21,7 @@
 #include <linux/bug.h>
 #include <linux/cache.h>
 #include <linux/rbtree.h>
+#include <linux/socket.h>
 
 #include <linux/atomic.h>
 #include <asm/types.h>
@@ -2639,6 +2640,11 @@ unsigned int datagram_poll(struct file *file, struct socket *sock,
 			   struct poll_table_struct *wait);
 int skb_copy_datagram_iovec(const struct sk_buff *from, int offset,
 			    struct iovec *to, int size);
+static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
+					struct msghdr *msg, int size)
+{
+	return skb_copy_datagram_iovec(from, offset, msg->msg_iov, size);
+}
 int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, int hlen,
 				     struct iovec *iov);
 int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset,