Re: [PATCH RFT RESEND linux-next] mips: dma-mapping: support debug_dma_mapping_error

Shuah Khan
2012-10-26T17:06:49Z

On Fri, 2012-10-26 at 09:45 -0700, David Daney wrote:
> On 10/26/2012 09:01 AM, Shuah Khan wrote:
> > Add support for debug_dma_mapping_error() call to avoid warning from
> > debug_dma_unmap() interface when it checks for mapping error checked
> > status. Without this patch, device driver failed to check map error
> > warning is generated.
> >
> > Signed-off-by: Shuah Khan <shuah.khan@hp.com>
> > ---
> > arch/mips/include/asm/dma-mapping.h | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/arch/mips/include/asm/dma-mapping.h b/arch/mips/include/asm/dma-mapping.h
> > index be39a12..006b43e 100644
> > --- a/arch/mips/include/asm/dma-mapping.h
> > +++ b/arch/mips/include/asm/dma-mapping.h
> > @@ -40,6 +40,8 @@ static inline int dma_supported(struct device *dev, u64 mask)
> > static inline int dma_mapping_error(struct device *dev, u64 mask)
> > {
> > struct dma_map_ops *ops = get_dma_ops(dev);
> > +
> > + debug_dma_mapping_error(dev, mask);
> > return ops->mapping_error(dev, mask);
> > }
> >
> >
>
> Although this is a start, I don't think it is sufficient.
>
> As far as I can tell, there are many missing calls to debug_dma_*() in
> the various MIPS commone and sub-architecture DMA code.
>
> Really you (or someone) needs to look at *all* the functions in
> arch/mips/asm/dma-mapping.h, and arch/mips/mm/dma-default.c and find
> places missing a debug_dma_*().

Is it correct to assume that this patch is not needed on MIPS until
debug_dma interfaces get added to MIPS common and sub-architecture DMA
code.

When I didn't see dma_map_page() in arch/mips/include/asm/dma-mapping.h
defined, and just an extern, I incorrectly assumed, it is getting picked
up from <asm-generic/dma-mapping-common.h>, hence the need for this
patch in the first place.

-- Shuah