Polite device drivers pad short packets to 60 bytes,
so that mean-spirited users don't accidentally DOS
some other OS that can't handle short packets.
Signed-off-by: Linas Vepstas <[EMAIL PROTECTED]>
Cc: James K Lewis <[EMAIL PROTECTED]>
Cc: Arnd Bergmann <[EMAIL PROTECTED]>
----
drivers/net/spider_net.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
Index: linux-2.6.18-mm2/drivers/net/spider_net.c
===================================================================
--- linux-2.6.18-mm2.orig/drivers/net/spider_net.c 2006-10-10
12:22:49.000000000 -0500
+++ linux-2.6.18-mm2/drivers/net/spider_net.c 2006-10-10 12:43:51.000000000
-0500
@@ -648,18 +648,26 @@ spider_net_prepare_tx_descr(struct spide
{
struct spider_net_descr *descr = card->tx_chain.head;
dma_addr_t buf;
+ int length;
- buf = pci_map_single(card->pdev, skb->data, skb->len, PCI_DMA_TODEVICE);
+ length = skb->len;
+ if (length < ETH_ZLEN) {
+ if (skb_pad(skb, ETH_ZLEN-length))
+ return 0;
+ length = ETH_ZLEN;
+ }
+
+ buf = pci_map_single(card->pdev, skb->data, length, PCI_DMA_TODEVICE);
if (pci_dma_mapping_error(buf)) {
if (netif_msg_tx_err(card) && net_ratelimit())
pr_err("could not iommu-map packet (%p, %i). "
- "Dropping packet\n", skb->data, skb->len);
+ "Dropping packet\n", skb->data, length);
card->spider_stats.tx_iommu_map_error++;
return -ENOMEM;
}
descr->buf_addr = buf;
- descr->buf_size = skb->len;
+ descr->buf_size = length;
descr->next_descr_addr = 0;
descr->skb = skb;
descr->data_status = 0;
@@ -693,6 +701,7 @@ spider_net_release_tx_descr(struct spide
{
struct spider_net_descr *descr = card->tx_chain.tail;
struct sk_buff *skb;
+ unsigned int len;
card->tx_chain.tail = card->tx_chain.tail->next;
descr->dmac_cmd_status |= SPIDER_NET_DESCR_NOT_IN_USE;
@@ -701,7 +710,8 @@ spider_net_release_tx_descr(struct spide
skb = descr->skb;
if (!skb)
return;
- pci_unmap_single(card->pdev, descr->buf_addr, skb->len,
+ len = skb->len < ETH_ZLEN ? ETH_ZLEN : skb->len;
+ pci_unmap_single(card->pdev, descr->buf_addr, len,
PCI_DMA_TODEVICE);
dev_kfree_skb_any(skb);
}
-
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