[PATCH] e100: Do pci_dma_sync after skb_alloc for proper operation on ixp4xx

[Kevin Hao <kexin.hao@windriver.com>]

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.

---
commit c1f24812b9de182a4272724a2e84ea1ae5dd4659
Author: Kevin Hao <kexin.hao@windriver.com>
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 <kexin.hao@windriver.com>

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