Re: [Bug 487894] New: sky2 0000:06:00.0: DMA-API: device driverfrees DMA memory with different size

[Joerg Roedel]

On Thu, Apr 02, 2009 at 08:08:06AM -0700, Stephen Hemminger wrote:
> On Thu, 2 Apr 2009 16:31:42 +0200
> Joerg Roedel <joerg.roedel@xxxxxxx> wrote:
> > Author: Joerg Roedel <joerg.roedel@xxxxxxx>
> > Date:   Thu Apr 2 15:55:55 2009 +0200
> > 
> >     x86/dma: unify definition of pci_unmap_addr* and pci_unmap_len macros
> >     
> >     Impact: unification of pci-dma macros and pci_32h removal
> >     
> >     This patch unifies the definition of the pci_unmap_addr*, pci_unmap_len*
> >     and DECLARE_PCI_UNMAP* macros. This makes sense because the pci_unmap
> >     functions are no longer no-ops anymore when the kernel runs with
> >     CONFIG_DMA_API_DEBUG. This also simplifies the port of x86_64 iommu
> >     drivers to 32 bit x86 and let us get rid of pci_32.h.
> >     
> >     Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
> 
> Would also like some more comments to explain to the kernel neophytes why
> the 32 bit version is no-op.  Do other arch have same issue?
> 
> 
> Acked-by: Stephen Hemminger <shemminger@xxxxxxxxxx>

Ok, changed the patch description to

x86/dma: unify definition of pci_unmap_addr* and pci_unmap_len macros

Impact: unification of pci-dma macros and pci_32.h removal

This patch unifies the definition of the pci_unmap_addr*, pci_unmap_len*
and DECLARE_PCI_UNMAP* macros. This makes sense because the pci_unmap
functions are no longer no-ops anymore when the kernel runs with
CONFIG_DMA_API_DEBUG. Without an iommu or DMA_API_DEBUG it is a no-op on 32 bit
because the dma mapping path returns a physical address and therefore the
dma-api implementation has no internal state which needs to be destroyed with
an unmap call.
This unification also simplifies the port of x86_64 iommu drivers to 32 bit x86
and let us get rid of pci_32.h.

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
Acked-by: Stephen Hemminger <shemminger@xxxxxxxxxx>


Joerg


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