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>

drivers/nfc/s3fwrn5/firmware.c

@@ -76,9 +76,9 @@ static int s3fwrn5_fw_prep_msg(struct s3fwrn5_fw_info *fw_info,
 	if (!skb)
 		return -ENOMEM;
 
-	memcpy(skb_put(skb, S3FWRN5_FW_HDR_SIZE), &hdr, S3FWRN5_FW_HDR_SIZE);
+	skb_put_data(skb, &hdr, S3FWRN5_FW_HDR_SIZE);
 	if (len)
-		memcpy(skb_put(skb, len), data, len);
+		skb_put_data(skb, data, len);
 
 	*msg = skb;
 

drivers/nfc/s3fwrn5/i2c.c

@@ -157,7 +157,7 @@ static int s3fwrn5_i2c_read(struct s3fwrn5_i2c_phy *phy)
 	if (!skb)
 		return -ENOMEM;
 
-	memcpy(skb_put(skb, hdr_size), hdr, hdr_size);
+	skb_put_data(skb, hdr, hdr_size);
 
 	if (data_len == 0)
 		goto out;