Messages in this thread Patch in this message | | | Date | Wed, 20 Jan 2010 09:41:03 +0000 | From | Jarek Poplawski <> | Subject | [PATCH] sky2: Fix WARNING: at lib/dma-debug.c:902 check_sync |
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[ previously: Re: [PATCH] af_packet: Don't use skb after dev_queue_xmit() ] On Tue, Jan 19, 2010 at 05:10:13PM -0800, Stephen Hemminger wrote: > On Tue, 19 Jan 2010 20:01:10 -0500 > Michael Breuer <mbreuer@majjas.com> wrote: > > > On 1/19/2010 5:45 PM, Jarek Poplawski wrote: > > > On Tue, Jan 19, 2010 at 03:06:01PM -0500, Michael Breuer wrote: > > > > > >> On 1/19/2010 2:59 PM, Jarek Poplawski wrote: > > >> > > >>> On Tue, Jan 19, 2010 at 10:47:27AM -0500, Michael Breuer wrote: > > >>> ... > > >>> > > >>>> Still get the warning... but now 60 bytes. > > >>>> Jan 19 10:43:50 mail kernel: ------------[ cut here ]------------ > > >>>> Jan 19 10:43:50 mail kernel: WARNING: at lib/dma-debug.c:902 ... > > That not only compiled, but it cleared the error as well. Additionally, > > I used to see a bit of a delay receiving the login prompt when first > > connecting to the box by ssh. That delay is gone with this patch. I'd > > guess that the warning wasn't quite as innocuous as I thought. > > Note: tested on 2.6.32.4. I'll leave this up for a bit before > > attempting to move back to head. > > Seems like an underlying bug in the DMA api. Maybe it just can't > handle operations on partial mapping. > > Other drivers with same problem: > bnx2, cassini, pcnet32, r8169, rrunner, skge, sungem, tg3,
It seems using the same length (even without pci_unmap_len()) is crucial here, but I hope maintainers (added to CC) will take care.
Btw, it's not tested yet, but it might affect CONFIG_DMAR problems.
Thanks, Jarek P. ----------------------->
Using pci_unmap_len(), with the same length as pci_map_single(), with pci_dma_sync_single_for_cpu()/_device() fixes this warning (2.6.32.4):
> Jan 19 10:43:50 mail kernel: WARNING: at lib/dma-debug.c:902 > check_sync+0xc1/0x43f() > Jan 19 10:43:50 mail kernel: Hardware name: System Product Name > Jan 19 10:43:50 mail kernel: sky2 0000:04:00.0: DMA-API: device driver > tries to sync DMA memory it has not allocated [device > address=0x0000000320a0b022] [size=60 bytes]
Reported-by: Michael Breuer <mbreuer@majjas.com> Tested-by: Michael Breuer <mbreuer@majjas.com> Signed-off-by: Jarek Poplawski <jarkao2@gmail.com> ---
drivers/net/sky2.c | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c index 7650f73..cdebdd3 100644 --- a/drivers/net/sky2.c +++ b/drivers/net/sky2.c @@ -2252,12 +2252,14 @@ static struct sk_buff *receive_copy(struct sky2_port *sky2, skb = netdev_alloc_skb_ip_align(sky2->netdev, length); if (likely(skb)) { pci_dma_sync_single_for_cpu(sky2->hw->pdev, re->data_addr, - length, PCI_DMA_FROMDEVICE); + pci_unmap_len(re, data_size), + PCI_DMA_FROMDEVICE); skb_copy_from_linear_data(re->skb, skb->data, length); skb->ip_summed = re->skb->ip_summed; skb->csum = re->skb->csum; pci_dma_sync_single_for_device(sky2->hw->pdev, re->data_addr, - length, PCI_DMA_FROMDEVICE); + pci_unmap_len(re, data_size), + PCI_DMA_FROMDEVICE); re->skb->ip_summed = CHECKSUM_NONE; skb_put(skb, length); }
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