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    SubjectRe: [PATCH] e100: Do pci_dma_sync after skb_alloc for proper operation on ixp4xx
    Kevin Hao wrote:
    > Hi,
    > The E100 device can't work on current kernel (2.6.26-rc6) and will cause
    > kernel corruption on intel ixdp4xx. This patch fix this regression.
    Hello, this is pretty much the same patch that Anders Grafström sent on
    6/18. I think it looks good; I am sorry I missed this. I think this
    can be ok'ed if folks can test it on a few different ARM platforms and
    of course x86.

    I am getting sinus surgery this Monday but I should be back in the
    office within a week. I will give it a try then. I will test it on an
    ixp425 board and an PXA255 board. Just so you know, I found the
    in-kernel packet generator to be a good test. I also found using the
    board as a router between wired and wireless devices to catch issues
    that led me to posting patches for this driver in the first place.


    > ---
    > commit c1f24812b9de182a4272724a2e84ea1ae5dd4659
    > Author: Kevin Hao <>
    > Date: Sat Jun 21 16:50:50 2008 +0800
    > e100: Do pci_dma_sync after skb_alloc for proper operation on ixp4xx
    > Do a DMA sync after we've allocated a new skb and link it with the previous
    > RFD. Otherwise the previous RFD may reference the previously freed skb
    > and cause kernel corruption.
    > Previously there was such a DMA sync at this place, but it was removed
    > by commit 7734f6e6bcd7ba78b00e93e74a4ddafd9886cdea.
    > Restoring this sync operation eliminates the regression.
    > Signed-off-by: Kevin Hao <>
    > diff --git a/drivers/net/e100.c b/drivers/net/e100.c
    > index f3cba5e..1037b13 100644
    > --- a/drivers/net/e100.c
    > +++ b/drivers/net/e100.c
    > @@ -1803,6 +1803,8 @@ static int e100_rx_alloc_skb(struct nic *nic, struct rx *rx)
    > if (rx->prev->skb) {
    > struct rfd *prev_rfd = (struct rfd *)rx->prev->skb->data;
    > put_unaligned_le32(rx->dma_addr, &prev_rfd->link);
    > + pci_dma_sync_single_for_device(nic->pdev, rx->prev->dma_addr,
    > + sizeof(struct rfd), PCI_DMA_TODEVICE);
    > }
    > return 0;
    > ---
    > Best Regards,
    > Kevin

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