networking: introduce and use skb_put_data()

A common pattern with skb_put() is to just want to memcpy()
some data into the new space, introduce skb_put_data() for
this.

An spatch similar to the one for skb_put_zero() converts many
of the places using it:

    @@
    identifier p, p2;
    expression len, skb, data;
    type t, t2;
    @@
    (
    -p = skb_put(skb, len);
    +p = skb_put_data(skb, data, len);
    |
    -p = (t)skb_put(skb, len);
    +p = skb_put_data(skb, data, len);
    )
    (
    p2 = (t2)p;
    -memcpy(p2, data, len);
    |
    -memcpy(p, data, len);
    )

    @@
    type t, t2;
    identifier p, p2;
    expression skb, data;
    @@
    t *p;
    ...
    (
    -p = skb_put(skb, sizeof(t));
    +p = skb_put_data(skb, data, sizeof(t));
    |
    -p = (t *)skb_put(skb, sizeof(t));
    +p = skb_put_data(skb, data, sizeof(t));
    )
    (
    p2 = (t2)p;
    -memcpy(p2, data, sizeof(*p));
    |
    -memcpy(p, data, sizeof(*p));
    )

    @@
    expression skb, len, data;
    @@
    -memcpy(skb_put(skb, len), data, len);
    +skb_put_data(skb, data, len);

(again, manually post-processed to retain some comments)

Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 4 deletions

diff --git a/net/ieee802154/6lowpan/tx.c b/net/ieee802154/6lowpan/tx.c
index dbb476d7d38f..e6ff5128e61a 100644
--- a/net/ieee802154/6lowpan/tx.c
+++ b/net/ieee802154/6lowpan/tx.c
@@ -121,8 +121,7 @@ lowpan_alloc_frag(struct sk_buff *skb, int size,
 		*mac_cb(frag) = *mac_cb(skb);
 
 		if (frag1) {
-			memcpy(skb_put(frag, skb->mac_len),
-			       skb_mac_header(skb), skb->mac_len);
+			skb_put_data(frag, skb_mac_header(skb), skb->mac_len);
 		} else {
 			rc = wpan_dev_hard_header(frag, wdev,
 						  &master_hdr->dest,
@@ -152,8 +151,8 @@ lowpan_xmit_fragment(struct sk_buff *skb, const struct ieee802154_hdr *wpan_hdr,
 	if (IS_ERR(frag))
 		return PTR_ERR(frag);
 
-	memcpy(skb_put(frag, frag_hdrlen), frag_hdr, frag_hdrlen);
-	memcpy(skb_put(frag, len), skb_network_header(skb) + offset, len);
+	skb_put_data(frag, frag_hdr, frag_hdrlen);
+	skb_put_data(frag, skb_network_header(skb) + offset, len);
 
 	raw_dump_table(__func__, " fragment dump", frag->data, frag->len);