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, 3 deletions

diff --git a/net/can/bcm.c b/net/can/bcm.c
index 6543263..47a8748d 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -282,7 +282,7 @@ static void bcm_can_tx(struct bcm_op *op)
 	can_skb_prv(skb)->ifindex = dev->ifindex;
 	can_skb_prv(skb)->skbcnt = 0;
 
-	memcpy(skb_put(skb, op->cfsiz), cf, op->cfsiz);
+	skb_put_data(skb, cf, op->cfsiz);
 
 	/* send with loopback */
 	skb->dev = dev;
@@ -318,13 +318,13 @@ static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
 	if (!skb)
 		return;
 
-	memcpy(skb_put(skb, sizeof(*head)), head, sizeof(*head));
+	skb_put_data(skb, head, sizeof(*head));
 
 	if (head->nframes) {
 		/* CAN frames starting here */
 		firstframe = (struct canfd_frame *)skb_tail_pointer(skb);
 
-		memcpy(skb_put(skb, datalen), frames, datalen);
+		skb_put_data(skb, frames, datalen);
 
 		/*
 		 * the BCM uses the flags-element of the canfd_frame