Re: [PATCH] ARM: DMA: Fix kzalloc flags in __iommu_alloc_buffer()

[Marek Szyprowski]

Hello,

On 2015-01-13 09:45, Alexandre Courbot wrote:
> Ping? This patch still seems to be needed as of today...

Arnd, could you take this patch together with your other pending 
dma-mapping.h changes?

> On Thu, Dec 11, 2014 at 8:12 PM, Marek Szyprowski
> <m.szyprowski@xxxxxxxxxxx> wrote:
> > On 2014-12-08 09:39, Alexandre Courbot wrote:
> > > There doesn't seem to be any valid reason to allocate the pages array
> > > with the same flags as the buffer itself. Doing so can eventually lead
> > > to the following safeguard in mm/slab.c to be hit:
> > >
> > > BUG_ON(flags & GFP_SLAB_BUG_MASK);
> > >
> > > This happens when buffers are allocated with __GFP_DMA32 or
> > > __GFP_HIGHMEM.
> > >
> > > Fix this by allocating the pages array with GFP_KERNEL to follow what is
> > > done elsewhere in this file. Using GFP_KERNEL in __iommu_alloc_buffer()
> > > is safe because atomic allocations are handled by __iommu_alloc_atomic().
> > >
> > > Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
> > > Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
> > > Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> > > Cc: Arnd Bergmann <arnd@xxxxxxxx>
> > > Cc: Thierry Reding <treding@xxxxxxxxxx>
> > > Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> > Acked-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> >
> > > ---
> > >    arch/arm/mm/dma-mapping.c | 2 +-
> > >    1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> > > index e8907117861e..bc495354c802 100644
> > > --- a/arch/arm/mm/dma-mapping.c
> > > +++ b/arch/arm/mm/dma-mapping.c
> > > @@ -1106,7 +1106,7 @@ static struct page **__iommu_alloc_buffer(struct
> > > device *dev, size_t size,
> > >          int i = 0;
> > >          if (array_size <= PAGE_SIZE)
> > > -               pages = kzalloc(array_size, gfp);
> > > +               pages = kzalloc(array_size, GFP_KERNEL);
> > >          else
> > >                  pages = vzalloc(array_size);
> > >          if (!pages)

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/