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, 5 insertions, 6 deletions

diff --git a/drivers/usb/gadget/function/f_ncm.c b/drivers/usb/gadget/function/f_ncm.c
index 2882c6d..630616a 100644
--- a/drivers/usb/gadget/function/f_ncm.c
+++ b/drivers/usb/gadget/function/f_ncm.c
@@ -1007,8 +1007,8 @@ static struct sk_buff *package_for_tx(struct f_ncm *ncm)
 	ntb_iter = skb_put_zero(skb2, ndp_pad);
 
 	/* Copy NTB across. */
-	ntb_iter = (void *) skb_put(skb2, ncm->skb_tx_ndp->len);
-	memcpy(ntb_iter, ncm->skb_tx_ndp->data, ncm->skb_tx_ndp->len);
+	ntb_iter = skb_put_data(skb2, ncm->skb_tx_ndp->data,
+				ncm->skb_tx_ndp->len);
 	dev_consume_skb_any(ncm->skb_tx_ndp);
 	ncm->skb_tx_ndp = NULL;
 
@@ -1129,8 +1129,7 @@ static struct sk_buff *ncm_wrap_ntb(struct gether *port,
 
 		/* Add the new data to the skb */
 		ntb_data = skb_put_zero(ncm->skb_tx_data, dgram_pad);
-		ntb_data = (void *) skb_put(ncm->skb_tx_data, skb->len);
-		memcpy(ntb_data, skb->data, skb->len);
+		ntb_data = skb_put_data(ncm->skb_tx_data, skb->data, skb->len);
 		dev_consume_skb_any(skb);
 		skb = NULL;
 
@@ -1313,8 +1312,8 @@ static int ncm_unwrap_ntb(struct gether *port,
 							 dg_len - crc_len);
 			if (skb2 == NULL)
 				goto err;
-			memcpy(skb_put(skb2, dg_len - crc_len),
-			       skb->data + index, dg_len - crc_len);
+			skb_put_data(skb2, skb->data + index,
+				     dg_len - crc_len);
 
 			skb_queue_tail(list, skb2);