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, 7 insertions, 8 deletions

diff --git a/net/nfc/llcp_commands.c b/net/nfc/llcp_commands.c
index c5959ce503e6..367d8c027101 100644
--- a/net/nfc/llcp_commands.c
+++ b/net/nfc/llcp_commands.c
@@ -298,7 +298,7 @@ static struct sk_buff *llcp_add_header(struct sk_buff *pdu,
 
 	pr_debug("header 0x%x 0x%x\n", header[0], header[1]);
 
-	memcpy(skb_put(pdu, LLCP_HEADER_SIZE), header, LLCP_HEADER_SIZE);
+	skb_put_data(pdu, header, LLCP_HEADER_SIZE);
 
 	return pdu;
 }
@@ -311,7 +311,7 @@ static struct sk_buff *llcp_add_tlv(struct sk_buff *pdu, u8 *tlv,
 	if (tlv == NULL)
 		return NULL;
 
-	memcpy(skb_put(pdu, tlv_length), tlv, tlv_length);
+	skb_put_data(pdu, tlv, tlv_length);
 
 	return pdu;
 }
@@ -549,7 +549,7 @@ int nfc_llcp_send_snl_sdres(struct nfc_llcp_local *local,
 		return PTR_ERR(skb);
 
 	hlist_for_each_entry_safe(sdp, n, tlv_list, node) {
-		memcpy(skb_put(skb, sdp->tlv_len), sdp->tlv, sdp->tlv_len);
+		skb_put_data(skb, sdp->tlv, sdp->tlv_len);
 
 		hlist_del(&sdp->node);
 
@@ -581,8 +581,7 @@ int nfc_llcp_send_snl_sdreq(struct nfc_llcp_local *local,
 	hlist_for_each_entry_safe(sdreq, n, tlv_list, node) {
 		pr_debug("tid %d for %s\n", sdreq->tid, sdreq->uri);
 
-		memcpy(skb_put(skb, sdreq->tlv_len), sdreq->tlv,
-		       sdreq->tlv_len);
+		skb_put_data(skb, sdreq->tlv, sdreq->tlv_len);
 
 		hlist_del(&sdreq->node);
 
@@ -622,7 +621,7 @@ int nfc_llcp_send_dm(struct nfc_llcp_local *local, u8 ssap, u8 dsap, u8 reason)
 
 	skb = llcp_add_header(skb, dsap, ssap, LLCP_PDU_DM);
 
-	memcpy(skb_put(skb, 1), &reason, 1);
+	skb_put_data(skb, &reason, 1);
 
 	skb_queue_head(&local->tx_queue, skb);
 
@@ -693,7 +692,7 @@ int nfc_llcp_send_i_frame(struct nfc_llcp_sock *sock,
 		skb_put(pdu, LLCP_SEQUENCE_SIZE);
 
 		if (likely(frag_len > 0))
-			memcpy(skb_put(pdu, frag_len), msg_ptr, frag_len);
+			skb_put_data(pdu, msg_ptr, frag_len);
 
 		skb_queue_tail(&sock->tx_queue, pdu);
 
@@ -759,7 +758,7 @@ int nfc_llcp_send_ui_frame(struct nfc_llcp_sock *sock, u8 ssap, u8 dsap,
 		pdu = llcp_add_header(pdu, dsap, ssap, LLCP_PDU_UI);
 
 		if (likely(frag_len > 0))
-			memcpy(skb_put(pdu, frag_len), msg_ptr, frag_len);
+			skb_put_data(pdu, msg_ptr, frag_len);
 
 		/* No need to check for the peer RW for UI frames */
 		skb_queue_tail(&local->tx_queue, pdu);