[SK_BUFF]: Introduce skb_copy_from_linear_data{_offset}

To clearly state the intent of copying from linear sk_buffs, _offset being a
overly long variant but interesting for the sake of saving some bytes.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/drivers/infiniband/hw/cxgb3/iwch_cm.c b/drivers/infiniband/hw/cxgb3/iwch_cm.c
index e842c65..3b4b0ac 100644
--- a/drivers/infiniband/hw/cxgb3/iwch_cm.c
+++ b/drivers/infiniband/hw/cxgb3/iwch_cm.c
@@ -821,7 +821,8 @@
 	/*
 	 * copy the new data into our accumulation buffer.
 	 */
-	memcpy(&(ep->mpa_pkt[ep->mpa_pkt_len]), skb->data, skb->len);
+	skb_copy_from_linear_data(skb, &(ep->mpa_pkt[ep->mpa_pkt_len]),
+				  skb->len);
 	ep->mpa_pkt_len += skb->len;
 
 	/*
@@ -940,7 +941,8 @@
 	/*
 	 * Copy the new data into our accumulation buffer.
 	 */
-	memcpy(&(ep->mpa_pkt[ep->mpa_pkt_len]), skb->data, skb->len);
+	skb_copy_from_linear_data(skb, &(ep->mpa_pkt[ep->mpa_pkt_len]),
+				  skb->len);
 	ep->mpa_pkt_len += skb->len;
 
 	/*
@@ -1619,7 +1621,8 @@
 	PDBG("%s ep %p\n", __FUNCTION__, ep);
 	skb_pull(skb, sizeof(struct cpl_rdma_terminate));
 	PDBG("%s saving %d bytes of term msg\n", __FUNCTION__, skb->len);
-	memcpy(ep->com.qp->attr.terminate_buffer, skb->data, skb->len);
+	skb_copy_from_linear_data(skb, ep->com.qp->attr.terminate_buffer,
+				  skb->len);
 	ep->com.qp->attr.terminate_msg_len = skb->len;
 	ep->com.qp->attr.is_terminate_local = 0;
 	return CPL_RET_BUF_DONE;