[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>
diff --git a/drivers/net/yellowfin.c b/drivers/net/yellowfin.c
index 9da9254..1c25065 100644
--- a/drivers/net/yellowfin.c
+++ b/drivers/net/yellowfin.c
@@ -786,7 +786,7 @@
skb->dev = dev; /* Mark as being used by this device. */
skb_reserve(skb, 2); /* 16 byte align the IP header. */
yp->rx_ring[i].addr = cpu_to_le32(pci_map_single(yp->pci_dev,
- skb->tail, yp->rx_buf_sz, PCI_DMA_FROMDEVICE));
+ skb->data, yp->rx_buf_sz, PCI_DMA_FROMDEVICE));
}
yp->rx_ring[i-1].dbdma_cmd = cpu_to_le32(CMD_STOP);
yp->dirty_rx = (unsigned int)(i - RX_RING_SIZE);
@@ -1111,7 +1111,7 @@
pci_dma_sync_single_for_cpu(yp->pci_dev, desc->addr,
yp->rx_buf_sz, PCI_DMA_FROMDEVICE);
desc_status = le32_to_cpu(desc->result_status) >> 16;
- buf_addr = rx_skb->tail;
+ buf_addr = rx_skb->data;
data_size = (le32_to_cpu(desc->dbdma_cmd) -
le32_to_cpu(desc->result_status)) & 0xffff;
frame_status = le16_to_cpu(get_unaligned((s16*)&(buf_addr[data_size - 2])));
@@ -1185,7 +1185,7 @@
break;
skb->dev = dev;
skb_reserve(skb, 2); /* 16 byte align the IP header */
- eth_copy_and_sum(skb, rx_skb->tail, pkt_len, 0);
+ eth_copy_and_sum(skb, rx_skb->data, pkt_len, 0);
skb_put(skb, pkt_len);
pci_dma_sync_single_for_device(yp->pci_dev, desc->addr,
yp->rx_buf_sz,
@@ -1211,7 +1211,7 @@
skb->dev = dev; /* Mark as being used by this device. */
skb_reserve(skb, 2); /* Align IP on 16 byte boundaries */
yp->rx_ring[entry].addr = cpu_to_le32(pci_map_single(yp->pci_dev,
- skb->tail, yp->rx_buf_sz, PCI_DMA_FROMDEVICE));
+ skb->data, yp->rx_buf_sz, PCI_DMA_FROMDEVICE));
}
yp->rx_ring[entry].dbdma_cmd = cpu_to_le32(CMD_STOP);
yp->rx_ring[entry].result_status = 0; /* Clear complete bit. */
