On Wed, 11 Jul 2007, Ivan Kokshaysky wrote:
> On Tue, Jul 10, 2007 at 09:25:50PM +0100, Hugh Dickins wrote:
> > On Mon, 9 Jul 2007, Bob Tracy wrote:
> > > That seems to have done the trick. Normally, I get the "bad page"
> > > errors on the second NX session, but I'm on the third session of the
> > > day (thus far), and everything seems to be ok as far as I can tell.
> >
> > Thanks a lot for the feedback, that tells us we've made the right
> > guesses, and my __GFP_COMP patch should be a good bandaid for you;
> > but for the right patch, let's wait to hear from Ivan.
>
> Here it is. Bob, can you test this one?
>
> ---
>
> Take care of DMA flags passed to dma_alloc_coherent().
> Particularly ALSA needs that.
>
> Signed-off-by: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Yes, I agree that's the right way to go. Aside from fixing Bob's
crash, it also liberates ALSA from needing GFP_ATOMIC there on Alpha.
Couple of GFP_ notes below.
Hugh
>
> Ivan.
>
> --- 2.6.22/arch/alpha/kernel/pci_iommu.c Mon Jul 9 03:32:17 2007
> +++ linux/arch/alpha/kernel/pci_iommu.c Wed Jul 11 14:40:37 2007
> @@ -398,11 +398,13 @@ EXPORT_SYMBOL(pci_unmap_page);
> else DMA_ADDRP is undefined. */
>
> void *
> -pci_alloc_consistent(struct pci_dev *pdev, size_t size, dma_addr_t *dma_addrp)
> +__pci_alloc_consistent(struct pci_dev *pdev, size_t size,
> + dma_addr_t *dma_addrp, gfp_t gfp)
> {
> void *cpu_addr;
> long order = get_order(size);
> - gfp_t gfp = GFP_ATOMIC;
> +
> + gfp &= ~GFP_DMA;
The canonical form for this masking, even on arches without HIGHMEM,
appears to be:
gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
But I guess that won't make any actual difference.
>
> try_again:
> cpu_addr = (void *)__get_free_pages(gfp, order);
> @@ -432,7 +434,7 @@ try_again:
>
> return cpu_addr;
> }
> -EXPORT_SYMBOL(pci_alloc_consistent);
> +EXPORT_SYMBOL(__pci_alloc_consistent);
>
> /* Free and unmap a consistent DMA buffer. CPU_ADDR and DMA_ADDR must
> be values that were returned from pci_alloc_consistent. SIZE must
> --- 2.6.22/include/asm-alpha/pci.h Mon Jul 9 03:32:17 2007
> +++ linux/include/asm-alpha/pci.h Wed Jul 11 14:40:37 2007
> @@ -75,7 +75,13 @@ extern inline void pcibios_penalize_isa_
> successful and sets *DMA_ADDRP to the pci side dma address as well,
> else DMA_ADDRP is undefined. */
>
> -extern void *pci_alloc_consistent(struct pci_dev *, size_t, dma_addr_t *);
> +extern void *__pci_alloc_consistent(struct pci_dev *, size_t,
> + dma_addr_t *, gfp_t);
> +static inline void *
> +pci_alloc_consistent(struct pci_dev *dev, size_t size, dma_addr_t *dma)
> +{
> + return __pci_alloc_consistent(dev, size, dma, GFP_ATOMIC);
I was going to ask you why that needs to be GFP_ATOMIC on Alpha.
But find you're following the example of asm-generic and others.
So really should be asking Sparc how it gets away with GFP_KERNEL.
> +}
>
> /* Free and unmap a consistent DMA buffer. CPU_ADDR and DMA_ADDR must
> be values that were returned from pci_alloc_consistent. SIZE must
> --- 2.6.22/include/asm-alpha/dma-mapping.h Mon Jul 9 03:32:17 2007
> +++ linux/include/asm-alpha/dma-mapping.h Wed Jul 11 14:40:37 2007
> @@ -11,7 +11,7 @@
> #define dma_unmap_single(dev, addr, size, dir) \
> pci_unmap_single(alpha_gendev_to_pci(dev), addr, size, dir)
> #define dma_alloc_coherent(dev, size, addr, gfp) \
> - pci_alloc_consistent(alpha_gendev_to_pci(dev), size, addr)
> + __pci_alloc_consistent(alpha_gendev_to_pci(dev), size, addr, gfp)
> #define dma_free_coherent(dev, size, va, addr) \
> pci_free_consistent(alpha_gendev_to_pci(dev), size, va, addr)
> #define dma_map_page(dev, page, off, size, dir) \
-
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