[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/net/wireless/atmel.c b/drivers/net/wireless/atmel.c
index 1c17cbe..51a7db5 100644
--- a/drivers/net/wireless/atmel.c
+++ b/drivers/net/wireless/atmel.c
@@ -827,14 +827,14 @@
 	if (priv->wep_is_on)
 		frame_ctl |= IEEE80211_FCTL_PROTECTED;
 	if (priv->operating_mode == IW_MODE_ADHOC) {
-		memcpy(&header.addr1, skb->data, 6);
+		skb_copy_from_linear_data(skb, &header.addr1, 6);
 		memcpy(&header.addr2, dev->dev_addr, 6);
 		memcpy(&header.addr3, priv->BSSID, 6);
 	} else {
 		frame_ctl |= IEEE80211_FCTL_TODS;
 		memcpy(&header.addr1, priv->CurrentBSSID, 6);
 		memcpy(&header.addr2, dev->dev_addr, 6);
-		memcpy(&header.addr3, skb->data, 6);
+		skb_copy_from_linear_data(skb, &header.addr3, 6);
 	}
 
 	if (priv->use_wpa)
diff --git a/drivers/net/wireless/bcm43xx/bcm43xx_dma.c b/drivers/net/wireless/bcm43xx/bcm43xx_dma.c
index 6e0dc76..e3d2e61 100644
--- a/drivers/net/wireless/bcm43xx/bcm43xx_dma.c
+++ b/drivers/net/wireless/bcm43xx/bcm43xx_dma.c
@@ -998,7 +998,8 @@
 			assert(0);
 			return;
 		}
-		memcpy(skb_put(bounce_skb, skb->len), skb->data, skb->len);
+		skb_copy_from_linear_data(skb, skb_put(bounce_skb, skb->len),
+					  skb->len);
 		dev_kfree_skb_any(skb);
 		skb = bounce_skb;
 	}
diff --git a/drivers/net/wireless/hostap/hostap_80211_rx.c b/drivers/net/wireless/hostap/hostap_80211_rx.c
index 35a3a50..cbedc9e 100644
--- a/drivers/net/wireless/hostap/hostap_80211_rx.c
+++ b/drivers/net/wireless/hostap/hostap_80211_rx.c
@@ -933,12 +933,14 @@
 		if (frag == 0) {
 			/* copy first fragment (including full headers) into
 			 * beginning of the fragment cache skb */
-			memcpy(skb_put(frag_skb, flen), skb->data, flen);
+			skb_copy_from_linear_data(skb, skb_put(frag_skb, flen),
+						  flen);
 		} else {
 			/* append frame payload to the end of the fragment
 			 * cache skb */
-			memcpy(skb_put(frag_skb, flen), skb->data + hdrlen,
-			       flen);
+			skb_copy_from_linear_data_offset(skb, hdrlen,
+							 skb_put(frag_skb,
+								 flen), flen);
 		}
 		dev_kfree_skb(skb);
 		skb = NULL;
@@ -1044,8 +1046,9 @@
 	    skb->len >= ETH_HLEN + ETH_ALEN) {
 		/* Non-standard frame: get addr4 from its bogus location after
 		 * the payload */
-		memcpy(skb->data + ETH_ALEN,
-		       skb->data + skb->len - ETH_ALEN, ETH_ALEN);
+		skb_copy_from_linear_data_offset(skb, skb->len - ETH_ALEN,
+						 skb->data + ETH_ALEN,
+						 ETH_ALEN);
 		skb_trim(skb, skb->len - ETH_ALEN);
 	}
 
diff --git a/drivers/net/wireless/hostap/hostap_80211_tx.c b/drivers/net/wireless/hostap/hostap_80211_tx.c
index 159baef..246fac0 100644
--- a/drivers/net/wireless/hostap/hostap_80211_tx.c
+++ b/drivers/net/wireless/hostap/hostap_80211_tx.c
@@ -146,7 +146,8 @@
 			fc |= IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS;
 			/* From&To DS: Addr1 = RA, Addr2 = TA, Addr3 = DA,
 			 * Addr4 = SA */
-			memcpy(&hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
+			skb_copy_from_linear_data_offset(skb, ETH_ALEN,
+							 &hdr.addr4, ETH_ALEN);
 			hdr_len += ETH_ALEN;
 		} else {
 			/* bogus 4-addr format to workaround Prism2 station
@@ -159,7 +160,8 @@
 			/* SA from skb->data + ETH_ALEN will be added after
 			 * frame payload; use hdr.addr4 as a temporary buffer
 			 */
-			memcpy(&hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
+			skb_copy_from_linear_data_offset(skb, ETH_ALEN,
+							 &hdr.addr4, ETH_ALEN);
 			need_tailroom += ETH_ALEN;
 		}
 
@@ -174,24 +176,27 @@
 		else
 			memcpy(&hdr.addr1, local->bssid, ETH_ALEN);
 		memcpy(&hdr.addr2, dev->dev_addr, ETH_ALEN);
-		memcpy(&hdr.addr3, skb->data, ETH_ALEN);
+		skb_copy_from_linear_data(skb, &hdr.addr3, ETH_ALEN);
 	} else if (local->iw_mode == IW_MODE_MASTER && !to_assoc_ap) {
 		fc |= IEEE80211_FCTL_FROMDS;
 		/* From DS: Addr1 = DA, Addr2 = BSSID, Addr3 = SA */
-		memcpy(&hdr.addr1, skb->data, ETH_ALEN);
+		skb_copy_from_linear_data(skb, &hdr.addr1, ETH_ALEN);
 		memcpy(&hdr.addr2, dev->dev_addr, ETH_ALEN);
-		memcpy(&hdr.addr3, skb->data + ETH_ALEN, ETH_ALEN);
+		skb_copy_from_linear_data_offset(skb, ETH_ALEN, &hdr.addr3,
+						 ETH_ALEN);
 	} else if (local->iw_mode == IW_MODE_INFRA || to_assoc_ap) {
 		fc |= IEEE80211_FCTL_TODS;
 		/* To DS: Addr1 = BSSID, Addr2 = SA, Addr3 = DA */
 		memcpy(&hdr.addr1, to_assoc_ap ?
 		       local->assoc_ap_addr : local->bssid, ETH_ALEN);
-		memcpy(&hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
-		memcpy(&hdr.addr3, skb->data, ETH_ALEN);
+		skb_copy_from_linear_data_offset(skb, ETH_ALEN, &hdr.addr2,
+						 ETH_ALEN);
+		skb_copy_from_linear_data(skb, &hdr.addr3, ETH_ALEN);
 	} else if (local->iw_mode == IW_MODE_ADHOC) {
 		/* not From/To DS: Addr1 = DA, Addr2 = SA, Addr3 = BSSID */
-		memcpy(&hdr.addr1, skb->data, ETH_ALEN);
-		memcpy(&hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
+		skb_copy_from_linear_data(skb, &hdr.addr1, ETH_ALEN);
+		skb_copy_from_linear_data_offset(skb, ETH_ALEN, &hdr.addr2,
+						 ETH_ALEN);
 		memcpy(&hdr.addr3, local->bssid, ETH_ALEN);
 	}
 
diff --git a/drivers/net/wireless/hostap/hostap_ap.c b/drivers/net/wireless/hostap/hostap_ap.c
index 797d950..4ca8a27 100644
--- a/drivers/net/wireless/hostap/hostap_ap.c
+++ b/drivers/net/wireless/hostap/hostap_ap.c
@@ -1277,8 +1277,8 @@
 		return NULL;
 	}
 
-	memcpy(tmpbuf, skb->data + ap->crypt->extra_mpdu_prefix_len,
-	       WLAN_AUTH_CHALLENGE_LEN);
+	skb_copy_from_linear_data_offset(skb, ap->crypt->extra_mpdu_prefix_len,
+					 tmpbuf, WLAN_AUTH_CHALLENGE_LEN);
 	dev_kfree_skb(skb);
 
 	return tmpbuf;
diff --git a/drivers/net/wireless/hostap/hostap_hw.c b/drivers/net/wireless/hostap/hostap_hw.c
index 9003ff7..fb01fb9 100644
--- a/drivers/net/wireless/hostap/hostap_hw.c
+++ b/drivers/net/wireless/hostap/hostap_hw.c
@@ -1838,13 +1838,14 @@
 
 	/* skb->data starts with txdesc->frame_control */
 	hdr_len = 24;
-	memcpy(&txdesc.frame_control, skb->data, hdr_len);
+	skb_copy_from_linear_data(skb, &txdesc.frame_control, hdr_len);
  	fc = le16_to_cpu(txdesc.frame_control);
 	if (WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA &&
 	    (fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS) &&
 	    skb->len >= 30) {
 		/* Addr4 */
-		memcpy(txdesc.addr4, skb->data + hdr_len, ETH_ALEN);
+		skb_copy_from_linear_data_offset(skb, hdr_len, txdesc.addr4,
+						 ETH_ALEN);
 		hdr_len += ETH_ALEN;
 	}
 
diff --git a/drivers/net/wireless/ipw2100.c b/drivers/net/wireless/ipw2100.c
index ad6e4a4..9137a4d 100644
--- a/drivers/net/wireless/ipw2100.c
+++ b/drivers/net/wireless/ipw2100.c
@@ -2416,8 +2416,9 @@
 #ifdef IPW2100_RX_DEBUG
 	/* Make a copy of the frame so we can dump it to the logs if
 	 * ieee80211_rx fails */
-	memcpy(packet_data, packet->skb->data,
-	       min_t(u32, status->frame_size, IPW_RX_NIC_BUFFER_LENGTH));
+	skb_copy_from_linear_data(packet->skb, packet_data,
+				  min_t(u32, status->frame_size,
+					     IPW_RX_NIC_BUFFER_LENGTH));
 #endif
 
 	if (!ieee80211_rx(priv->ieee, packet->skb, stats)) {
diff --git a/drivers/net/wireless/ipw2200.c b/drivers/net/wireless/ipw2200.c
index b04c56a..4839a45 100644
--- a/drivers/net/wireless/ipw2200.c
+++ b/drivers/net/wireless/ipw2200.c
@@ -10355,7 +10355,7 @@
 
 		rt_hdr->it_len = dst->len;
 
-		memcpy(skb_put(dst, len), src->data, len);
+		skb_copy_from_linear_data(src, skb_put(dst, len), len);
 
 		if (!ieee80211_rx(priv->prom_priv->ieee, dst, &dummystats))
 			dev_kfree_skb_any(dst);
diff --git a/drivers/net/wireless/prism54/islpci_eth.c b/drivers/net/wireless/prism54/islpci_eth.c
index 6ebfff0..7d8bff1 100644
--- a/drivers/net/wireless/prism54/islpci_eth.c
+++ b/drivers/net/wireless/prism54/islpci_eth.c
@@ -162,13 +162,16 @@
 
 			skb_put(newskb, init_wds ? skb->len + 6 : skb->len);
 			if (init_wds) {
-				memcpy(newskb->data + 6, skb->data, skb->len);
+				skb_copy_from_linear_data(skb,
+							  newskb->data + 6,
+							  skb->len);
 				memcpy(newskb->data, wds_mac, 6);
 #ifdef ISLPCI_ETH_DEBUG
 				printk("islpci_eth_transmit:wds_mac\n");
 #endif
 			} else
-				memcpy(newskb->data, skb->data, skb->len);
+				skb_copy_from_linear_data(skb, newskb->data,
+							  skb->len);
 
 #if VERBOSE > SHOW_ERROR_MESSAGES
 			DEBUG(SHOW_TRACING, "memcpy %p %p %i wds %i\n",
@@ -394,8 +397,10 @@
 			/* Update spy records */
 			wireless_spy_update(ndev, annex->addr2, &wstats);
 
-			memcpy(skb->data + sizeof (struct rfmon_header),
-			       skb->data, 2 * ETH_ALEN);
+			skb_copy_from_linear_data(skb,
+						  (skb->data +
+						   sizeof(struct rfmon_header)),
+						  2 * ETH_ALEN);
 			skb_pull(skb, sizeof (struct rfmon_header));
 		}
 		skb->protocol = eth_type_trans(skb, ndev);
diff --git a/drivers/net/wireless/ray_cs.c b/drivers/net/wireless/ray_cs.c
index 9633b04..3be6242 100644
--- a/drivers/net/wireless/ray_cs.c
+++ b/drivers/net/wireless/ray_cs.c
@@ -2242,7 +2242,8 @@
     rx_ptr += copy_from_rx_buff(local, rx_ptr, pkt_addr & RX_BUFF_END, rx_len);
     /* Get source address */
 #ifdef WIRELESS_SPY
-    memcpy(linksrcaddr, ((struct mac_header *)skb->data)->addr_2, ETH_ALEN);
+    skb_copy_from_linear_data_offset(skb, offsetof(struct mac_header, addr_2),
+				     linksrcaddr, ETH_ALEN);
 #endif
     /* Now, deal with encapsulation/translation/sniffer */
     if (!sniffer) {
diff --git a/drivers/net/wireless/wavelan.c b/drivers/net/wireless/wavelan.c
index 2bf77b1..1cf090d6 100644
--- a/drivers/net/wireless/wavelan.c
+++ b/drivers/net/wireless/wavelan.c
@@ -2938,7 +2938,7 @@
 	 * need to pad. Jean II */
 	if (skb->len < ETH_ZLEN) {
 		memset(data, 0, ETH_ZLEN);
-		memcpy(data, skb->data, skb->len);
+		skb_copy_from_linear_data(skb, data, skb->len);
 		/* Write packet on the card */
 		if(wv_packet_write(dev, data, ETH_ZLEN))
 			return 1;	/* We failed */
diff --git a/drivers/net/wireless/zd1201.c b/drivers/net/wireless/zd1201.c
index 1fe013a..935b144 100644
--- a/drivers/net/wireless/zd1201.c
+++ b/drivers/net/wireless/zd1201.c
@@ -807,10 +807,10 @@
 	txbuf[4] = 0x00;
 	txbuf[5] = 0x00;
 
-	memcpy(txbuf+6, skb->data+12, skb->len-12);
+	skb_copy_from_linear_data_offset(skb, 12, txbuf + 6, skb->len - 12);
 	if (pad)
 		txbuf[skb->len-12+6]=0;
-	memcpy(txbuf+skb->len-12+6+pad, skb->data, 12);
+	skb_copy_from_linear_data(skb, txbuf + skb->len - 12 + 6 + pad, 12);
 	*(__be16*)&txbuf[skb->len+6+pad] = htons(skb->len-12+6);
 	txbuf[txbuflen-1] = 0;