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, 8 insertions, 13 deletions

diff --git a/net/x25/x25_subr.c b/net/x25/x25_subr.c
index 6b5af65f491f..eb466ece1730 100644
--- a/net/x25/x25_subr.c
+++ b/net/x25/x25_subr.c
@@ -188,17 +188,14 @@ void x25_write_internal(struct sock *sk, int frametype)
                         *dptr++ = X25_CALL_REQUEST;
                         len     = x25_addr_aton(addresses, &x25->dest_addr,
                                                 &x25->source_addr);
-                        dptr    = skb_put(skb, len);
-                        memcpy(dptr, addresses, len);
+                        dptr = skb_put_data(skb, addresses, len);
                         len     = x25_create_facilities(facilities,
                                         &x25->facilities,
                                         &x25->dte_facilities,
                                         x25->neighbour->global_facil_mask);
-                        dptr    = skb_put(skb, len);
-                        memcpy(dptr, facilities, len);
-                        dptr = skb_put(skb, x25->calluserdata.cudlength);
-                        memcpy(dptr, x25->calluserdata.cuddata,
-                               x25->calluserdata.cudlength);
+                        dptr = skb_put_data(skb, facilities, len);
+                        dptr = skb_put_data(skb, x25->calluserdata.cuddata,
+                                            x25->calluserdata.cudlength);
                         x25->calluserdata.cudlength = 0;
                         break;
 
@@ -210,17 +207,15 @@ void x25_write_internal(struct sock *sk, int frametype)
                                                         &x25->facilities,
                                                         &x25->dte_facilities,
                                                         x25->vc_facil_mask);
-                        dptr    = skb_put(skb, len);
-                        memcpy(dptr, facilities, len);
+                        dptr = skb_put_data(skb, facilities, len);
 
                         /* fast select with no restriction on response
                                 allows call user data. Userland must
                                 ensure it is ours and not theirs */
                         if(x25->facilities.reverse & 0x80) {
-                                dptr = skb_put(skb,
-                                        x25->calluserdata.cudlength);
-                                memcpy(dptr, x25->calluserdata.cuddata,
-                                       x25->calluserdata.cudlength);
+                                dptr = skb_put_data(skb,
+                                                    x25->calluserdata.cuddata,
+                                                    x25->calluserdata.cudlength);
                         }
                         x25->calluserdata.cudlength = 0;
                         break;