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>
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index e45c8d9..861697f 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -345,7 +345,7 @@ int mesh_add_vendor_ies(struct ieee80211_sub_if_data *sdata,
 		data = ifmsh->ie + offset;
 		if (skb_tailroom(skb) < len)
 			return -ENOMEM;
-		memcpy(skb_put(skb, len), data, len);
+		skb_put_data(skb, data, len);
 	}
 
 	return 0;
@@ -369,7 +369,7 @@ int mesh_add_rsn_ie(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 
 	if (skb_tailroom(skb) < len)
 		return -ENOMEM;
-	memcpy(skb_put(skb, len), data, len);
+	skb_put_data(skb, data, len);
 
 	return 0;
 }
@@ -1125,8 +1125,8 @@ ieee80211_mesh_rx_probe_req(struct ieee80211_sub_if_data *sdata,
 		goto out;
 
 	skb_reserve(presp, local->tx_headroom);
-	memcpy(skb_put(presp, bcn->head_len), bcn->head, bcn->head_len);
-	memcpy(skb_put(presp, bcn->tail_len), bcn->tail, bcn->tail_len);
+	skb_put_data(presp, bcn->head, bcn->head_len);
+	skb_put_data(presp, bcn->tail, bcn->tail_len);
 	hdr = (struct ieee80211_mgmt *) presp->data;
 	hdr->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 					 IEEE80211_STYPE_PROBE_RESP);