[NET]: Remove gratuitous use of skb->tail in network drivers.

Many drivers use skb->tail unnecessarily.

In these situations, the code roughly looks like:

	dev = dev_alloc_skb(...);

	[optional] skb_reserve(skb, ...);

	... skb->tail ...

But even if the skb_reserve() happens, skb->data equals
skb->tail.  So it doesn't make any sense to use anything
other than skb->data in these cases.

Another case was the s2io.c driver directly mucking with
the skb->data and skb->tail pointers.  It really just wanted
to do an skb_reserve(), so that's what the code was changed
to do instead.

Another reason I'm making this change as it allows some SKB
cleanups I have planned simpler to merge.  In those cleanups,
skb->head, skb->tail, and skb->end pointers are removed, and
replaced with skb->head_room and skb->tail_room integers.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Jeff Garzik <jgarzik@pobox.com>

6 files changed, 19 insertions, 19 deletions

diff --git a/drivers/net/tulip/de2104x.c b/drivers/net/tulip/de2104x.c
index dd357dd8c370..fc353e348f9a 100644
--- a/drivers/net/tulip/de2104x.c
+++ b/drivers/net/tulip/de2104x.c
@@ -446,13 +446,13 @@ static void de_rx (struct de_private *de)
 
                         mapping =
                         de->rx_skb[rx_tail].mapping =
-                                pci_map_single(de->pdev, copy_skb->tail,
+                                pci_map_single(de->pdev, copy_skb->data,
                                                buflen, PCI_DMA_FROMDEVICE);
                         de->rx_skb[rx_tail].skb = copy_skb;
                 } else {
                         pci_dma_sync_single_for_cpu(de->pdev, mapping, len, PCI_DMA_FROMDEVICE);
                         skb_reserve(copy_skb, RX_OFFSET);
-                        memcpy(skb_put(copy_skb, len), skb->tail, len);
+                        memcpy(skb_put(copy_skb, len), skb->data, len);
 
                         pci_dma_sync_single_for_device(de->pdev, mapping, len, PCI_DMA_FROMDEVICE);
 
@@ -1269,7 +1269,7 @@ static int de_refill_rx (struct de_private *de)
                 skb->dev = de->dev;
 
                 de->rx_skb[i].mapping = pci_map_single(de->pdev,
-                        skb->tail, de->rx_buf_sz, PCI_DMA_FROMDEVICE);
+                        skb->data, de->rx_buf_sz, PCI_DMA_FROMDEVICE);
                 de->rx_skb[i].skb = skb;
 
                 de->rx_ring[i].opts1 = cpu_to_le32(DescOwn);
diff --git a/drivers/net/tulip/dmfe.c b/drivers/net/tulip/dmfe.c
index 7b899702ceb9..74e9075d9c48 100644
--- a/drivers/net/tulip/dmfe.c
+++ b/drivers/net/tulip/dmfe.c
@@ -945,8 +945,8 @@ static void dmfe_rx_packet(struct DEVICE *dev, struct dmfe_board_info * db)
 
                                 /* Received Packet CRC check need or not */
                                 if ( (db->dm910x_chk_mode & 1) &&
-                                        (cal_CRC(skb->tail, rxlen, 1) !=
-                                        (*(u32 *) (skb->tail+rxlen) ))) { /* FIXME (?) */
+                                        (cal_CRC(skb->data, rxlen, 1) !=
+                                        (*(u32 *) (skb->data+rxlen) ))) { /* FIXME (?) */
                                         /* Found a error received packet */
                                         dmfe_reuse_skb(db, rxptr->rx_skb_ptr);
                                         db->dm910x_chk_mode = 3;
@@ -959,7 +959,7 @@ static void dmfe_rx_packet(struct DEVICE *dev, struct dmfe_board_info * db)
                                                 /* size less than COPY_SIZE, allocate a rxlen SKB */
                                                 skb->dev = dev;
                                                 skb_reserve(skb, 2); /* 16byte align */
-                                                memcpy(skb_put(skb, rxlen), rxptr->rx_skb_ptr->tail, rxlen);
+                                                memcpy(skb_put(skb, rxlen), rxptr->rx_skb_ptr->data, rxlen);
                                                 dmfe_reuse_skb(db, rxptr->rx_skb_ptr);
                                         } else {
                                                 skb->dev = dev;
@@ -1252,7 +1252,7 @@ static void dmfe_reuse_skb(struct dmfe_board_info *db, struct sk_buff * skb)
 
         if (!(rxptr->rdes0 & cpu_to_le32(0x80000000))) {
                 rxptr->rx_skb_ptr = skb;
-                rxptr->rdes2 = cpu_to_le32( pci_map_single(db->pdev, skb->tail, RX_ALLOC_SIZE, PCI_DMA_FROMDEVICE) );
+                rxptr->rdes2 = cpu_to_le32( pci_map_single(db->pdev, skb->data, RX_ALLOC_SIZE, PCI_DMA_FROMDEVICE) );
                 wmb();
                 rxptr->rdes0 = cpu_to_le32(0x80000000);
                 db->rx_avail_cnt++;
@@ -1463,7 +1463,7 @@ static void allocate_rx_buffer(struct dmfe_board_info *db)
                 if ( ( skb = dev_alloc_skb(RX_ALLOC_SIZE) ) == NULL )
                         break;
                 rxptr->rx_skb_ptr = skb; /* FIXME (?) */
-                rxptr->rdes2 = cpu_to_le32( pci_map_single(db->pdev, skb->tail, RX_ALLOC_SIZE, PCI_DMA_FROMDEVICE) );
+                rxptr->rdes2 = cpu_to_le32( pci_map_single(db->pdev, skb->data, RX_ALLOC_SIZE, PCI_DMA_FROMDEVICE) );
                 wmb();
                 rxptr->rdes0 = cpu_to_le32(0x80000000);
                 rxptr = rxptr->next_rx_desc;
diff --git a/drivers/net/tulip/interrupt.c b/drivers/net/tulip/interrupt.c
index afb5cda9d8e1..bb3558164a5b 100644
--- a/drivers/net/tulip/interrupt.c
+++ b/drivers/net/tulip/interrupt.c
@@ -78,7 +78,7 @@ int tulip_refill_rx(struct net_device *dev)
                         if (skb == NULL)
                                 break;
 
-                        mapping = pci_map_single(tp->pdev, skb->tail, PKT_BUF_SZ,
+                        mapping = pci_map_single(tp->pdev, skb->data, PKT_BUF_SZ,
                                                  PCI_DMA_FROMDEVICE);
                         tp->rx_buffers[entry].mapping = mapping;
 
@@ -199,12 +199,12 @@ int tulip_poll(struct net_device *dev, int *budget)
                                                                    tp->rx_buffers[entry].mapping,
                                                                    pkt_len, PCI_DMA_FROMDEVICE);
 #if ! defined(__alpha__)
-                                       eth_copy_and_sum(skb, tp->rx_buffers[entry].skb->tail,
+                                       eth_copy_and_sum(skb, tp->rx_buffers[entry].skb->data,
                                                         pkt_len, 0);
                                        skb_put(skb, pkt_len);
 #else
                                        memcpy(skb_put(skb, pkt_len),
-                                              tp->rx_buffers[entry].skb->tail,
+                                              tp->rx_buffers[entry].skb->data,
                                               pkt_len);
 #endif
                                        pci_dma_sync_single_for_device(tp->pdev,
@@ -423,12 +423,12 @@ static int tulip_rx(struct net_device *dev)
                                                             tp->rx_buffers[entry].mapping,
                                                             pkt_len, PCI_DMA_FROMDEVICE);
 #if ! defined(__alpha__)
-                                eth_copy_and_sum(skb, tp->rx_buffers[entry].skb->tail,
+                                eth_copy_and_sum(skb, tp->rx_buffers[entry].skb->data,
                                                  pkt_len, 0);
                                 skb_put(skb, pkt_len);
 #else
                                 memcpy(skb_put(skb, pkt_len),
-                                       tp->rx_buffers[entry].skb->tail,
+                                       tp->rx_buffers[entry].skb->data,
                                        pkt_len);
 #endif
                                 pci_dma_sync_single_for_device(tp->pdev,
diff --git a/drivers/net/tulip/tulip_core.c b/drivers/net/tulip/tulip_core.c
index 08e0f80f89d5..d45d8f56e5b4 100644
--- a/drivers/net/tulip/tulip_core.c
+++ b/drivers/net/tulip/tulip_core.c
@@ -625,7 +625,7 @@ static void tulip_init_ring(struct net_device *dev)
                 tp->rx_buffers[i].skb = skb;
                 if (skb == NULL)
                         break;
-                mapping = pci_map_single(tp->pdev, skb->tail,
+                mapping = pci_map_single(tp->pdev, skb->data,
                                          PKT_BUF_SZ, PCI_DMA_FROMDEVICE);
                 tp->rx_buffers[i].mapping = mapping;
                 skb->dev = dev;                 /* Mark as being used by this device. */
diff --git a/drivers/net/tulip/winbond-840.c b/drivers/net/tulip/winbond-840.c
index db4b32c2369a..5b1af3986abf 100644
--- a/drivers/net/tulip/winbond-840.c
+++ b/drivers/net/tulip/winbond-840.c
@@ -849,7 +849,7 @@ static void init_rxtx_rings(struct net_device *dev)
                 if (skb == NULL)
                         break;
                 skb->dev = dev;                 /* Mark as being used by this device. */
-                np->rx_addr[i] = pci_map_single(np->pci_dev,skb->tail,
+                np->rx_addr[i] = pci_map_single(np->pci_dev,skb->data,
                                         skb->len,PCI_DMA_FROMDEVICE);
 
                 np->rx_ring[i].buffer1 = np->rx_addr[i];
@@ -1269,7 +1269,7 @@ static int netdev_rx(struct net_device *dev)
                                 pci_dma_sync_single_for_cpu(np->pci_dev,np->rx_addr[entry],
                                                             np->rx_skbuff[entry]->len,
                                                             PCI_DMA_FROMDEVICE);
-                                eth_copy_and_sum(skb, np->rx_skbuff[entry]->tail, pkt_len, 0);
+                                eth_copy_and_sum(skb, np->rx_skbuff[entry]->data, pkt_len, 0);
                                 skb_put(skb, pkt_len);
                                 pci_dma_sync_single_for_device(np->pci_dev,np->rx_addr[entry],
                                                                np->rx_skbuff[entry]->len,
@@ -1315,7 +1315,7 @@ static int netdev_rx(struct net_device *dev)
                                 break;                  /* Better luck next round. */
                         skb->dev = dev;                 /* Mark as being used by this device. */
                         np->rx_addr[entry] = pci_map_single(np->pci_dev,
-                                                        skb->tail,
+                                                        skb->data,
                                                         skb->len, PCI_DMA_FROMDEVICE);
                         np->rx_ring[entry].buffer1 = np->rx_addr[entry];
                 }
diff --git a/drivers/net/tulip/xircom_tulip_cb.c b/drivers/net/tulip/xircom_tulip_cb.c
index b8a9b395c5ea..887d7245fe7b 100644
--- a/drivers/net/tulip/xircom_tulip_cb.c
+++ b/drivers/net/tulip/xircom_tulip_cb.c
@@ -899,7 +899,7 @@ static void xircom_init_ring(struct net_device *dev)
                         break;
                 skb->dev = dev;                 /* Mark as being used by this device. */
                 tp->rx_ring[i].status = Rx0DescOwned;   /* Owned by Xircom chip */
-                tp->rx_ring[i].buffer1 = virt_to_bus(skb->tail);
+                tp->rx_ring[i].buffer1 = virt_to_bus(skb->data);
         }
         tp->dirty_rx = (unsigned int)(i - RX_RING_SIZE);
 
@@ -1291,7 +1291,7 @@ xircom_rx(struct net_device *dev)
                         if (skb == NULL)
                                 break;
                         skb->dev = dev;                 /* Mark as being used by this device. */
-                        tp->rx_ring[entry].buffer1 = virt_to_bus(skb->tail);
+                        tp->rx_ring[entry].buffer1 = virt_to_bus(skb->data);
                         work_done++;
                 }
                 tp->rx_ring[entry].status = Rx0DescOwned;