On Thu, Jun 20, 2013 at 10:35:11PM +0800, Hiroshi Doyu wrote: > Richard Zhao <linuxzsc@xxxxxxxxx> wrote @ Thu, 20 Jun 2013 15:40:50 +0200: > > > >> + /* > > >> + * Following is a work-around (a.k.a. hack) to prevent pages > > >> + * with __GFP_COMP being passed to split_page() which cannot > > >> + * handle them. The real problem is that this flag probably > > >> + * should be 0 on ARM as it is not supported on this > > >> + * platform; see CONFIG_HUGETLBFS. > > >> + */ > > >> + gfp &= ~(__GFP_COMP); > > > > > > > > > Hm, what exactly is the sense you meant in using ()? > > > > It's copy/paste from elsewhere in this file. At least it's consistent? :) > > I almost sent the exact same one, actually it was under internal reivew;) Ah, sorry I didn't search internal mails but only arm mail list for related fix, since I thought it's not specific to tegra. Why not give it a Reviewed-by or Tested-by? > > This patch is similar but is the iommu version of: Exactly. Thanks Richard > > > commit ea2e7057c0234cfb8b09467d8f137760d371fc72 > Author: Sumit Bhattacharya <sumitb@xxxxxxxxxx> > Date: Thu Nov 24 00:47:12 2011 +0100 > > ARM: 7172/1: dma: Drop GFP_COMP for DMA memory allocations > > dma_alloc_coherent wants to split pages after allocation in order to > reduce the memory footprint. This does not work well with GFP_COMP > pages, so drop this flag before allocation. > > This patch is ported from arch/avr32 > (commit 3611553ef985ef7c5863c8a94641738addd04cff). > > [swarren: s/HUGETLB_PAGE/HUGETLBFS/ in comment, minor comment cleanup] > > Signed-off-by: Sumit Bhattacharya <sumitb@xxxxxxxxxx> > Tested-by: Varun Colbert <vcolbert@xxxxxxxxxx> > Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx> > Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > index ab58456..1aa664a 100644 > --- a/arch/arm/mm/dma-mapping.c > +++ b/arch/arm/mm/dma-mapping.c > @@ -332,6 +332,15 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, > struct page *page; > void *addr; > > + /* > + * Following is a work-around (a.k.a. hack) to prevent pages > + * with __GFP_COMP being passed to split_page() which cannot > + * handle them. The real problem is that this flag probably > + * should be 0 on ARM as it is not supported on this > + * platform; see CONFIG_HUGETLBFS. > + */ > + gfp &= ~(__GFP_COMP); > + > *handle = ~0; > size = PAGE_ALIGN(size); -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
