Re: [PATCH] dma-debug: hash_bucket_find needs to allow for offsetswithin an entry (v2)

From: Neil Horman
Date: Wed Aug 10 2011 - 10:47:39 EST

On Wed, Aug 10, 2011 at 03:31:59PM +0200, Roedel, Joerg wrote:
> On Mon, Aug 08, 2011 at 03:13:54PM -0400, Neil Horman wrote:
> > dma-debug: hash_bucket_find needs to allow for offsets within an entry (v2)
> >
> > Summary:
> > Users of the pci_dma_sync_single_* api allow users to sync address ranges within
> > the range of a mapped entry (i.e. you can dma map address X to dma_addr_t A and
> > then pci_dma_sync_single on dma_addr_t A+1. The dma-debug library however
> > assume dma syncs will always occur using the base address of a mapped region,
> > and uses that assumption to find entries in its hash table. Since thats often
> > (but not always the case), the dma debug library can give us false errors about
> > missing entries, which are reported as syncing of memory not allocated by the
> > driver. This was noted in the cxgb3 driver as this error:
> Hi Neil,
> thanks for your patch. Im out-of-office this week and traveling next
> week. So it may take a couple of days until I can take an in-depth look
> at it. But I get to it as soon as I can :-)
> Regards,
> Joerg
No worries, don't rush. Thank you for letting me know.

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