On Tue, 9 Jan 2007 09:42:03 +0100
Ingo Oeser <[EMAIL PROTECTED]> wrote:
> Hi Stephen,
>
> Stephen Hemminger schrieb:
> > --- netdev-2.6.orig/drivers/net/chelsio/sge.c
> > +++ netdev-2.6/drivers/net/chelsio/sge.c
> [...]
> > @@ -1043,45 +1046,42 @@ static void recycle_fl_buf(struct freelQ
> > * be copied but there is no memory for the copy.
> > */
> > static inline struct sk_buff *get_packet(struct pci_dev *pdev,
> > - struct freelQ *fl, unsigned int len,
> > - int dma_pad, int skb_pad,
> > - unsigned int copy_thres,
> > - unsigned int drop_thres)
> > + struct freelQ *fl, unsigned int len)
> > {
> > struct sk_buff *skb;
> > - struct freelQ_ce *ce = &fl->centries[fl->cidx];
> > + const struct freelQ_ce *ce = &fl->centries[fl->cidx];
> >
> > - if (len < copy_thres) {
> > - skb = alloc_skb(len + skb_pad, GFP_ATOMIC);
> > - if (likely(skb != NULL)) {
> > - skb_reserve(skb, skb_pad);
> > - skb_put(skb, len);
> > - pci_dma_sync_single_for_cpu(pdev,
> > - pci_unmap_addr(ce, dma_addr),
> > - pci_unmap_len(ce, dma_len),
> > - PCI_DMA_FROMDEVICE);
> > - memcpy(skb->data, ce->skb->data + dma_pad, len);
> > - pci_dma_sync_single_for_device(pdev,
> > + if (len < copybreak) {
> > + skb = alloc_skb(len + 2, GFP_ATOMIC);
> > + if (!skb)
> > + goto use_orig_buf;
> > +
> > + skb_reserve(skb, 2); /* align IP header */
>
> Please use NET_IP_ALIGN here:
Wrong, NET_IP_ALIGN is intended to deal with platforms where alignment of DMA
is more
important of alignment of structures. Therefore if data is copied, it should
always be 2.
>
> + skb = alloc_skb(len + NET_IP_ALIGN, GFP_ATOMIC);
> + if (!skb)
> + goto use_orig_buf;
> +
> + skb_reserve(skb, NET_IP_ALIGN);
>
> > + skb_put(skb, len);
> > + pci_dma_sync_single_for_cpu(pdev,
> > pci_unmap_addr(ce, dma_addr),
> > pci_unmap_len(ce, dma_len),
> > PCI_DMA_FROMDEVICE);
> > - } else if (!drop_thres)
> > - goto use_orig_buf;
> > -
> > + memcpy(skb->data, ce->skb->data, len);
> > + pci_dma_sync_single_for_device(pdev,
> > + pci_unmap_addr(ce, dma_addr),
> > + pci_unmap_len(ce, dma_len),
> > + PCI_DMA_FROMDEVICE);
> > recycle_fl_buf(fl, fl->cidx);
> > return skb;
> > }
> >
> > - if (fl->credits < drop_thres) {
> > +use_orig_buf:
> > + if (fl->credits < 2) {
>
> Why 2? What does this magic number mean?
No idea, it was there in the original. (as a parameter).
--
Stephen Hemminger <[EMAIL PROTECTED]>
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