Messages in this thread Patch in this message |  | | Date | Wed, 16 Jan 2013 23:14:01 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [PATCH v2 1/1] block: blk-merge: don't merge the pages with non-contiguous descriptors |
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On Wed, Jan 16, 2013 at 10:32:35AM +0000, James Bottomley wrote: > On Wed, 2013-01-16 at 12:07 +0530, Subhash Jadavani wrote: > > > Now consider this call stack from MMC block driver (this is on the ARmv7 > > based board): > > [ 98.918174] [<c001b50c>] (v7_dma_inv_range+0x30/0x48) from > > [<c0017b8c>] (dma_cache_maint_page+0x1c4/0x24c) > > [ 98.927819] [<c0017b8c>] (dma_cache_maint_page+0x1c4/0x24c) from > > [<c0017c28>] (___dma_page_cpu_to_dev+0x14/0x1c) > > [ 98.937982] [<c0017c28>] (___dma_page_cpu_to_dev+0x14/0x1c) from > > [<c0017ff8>] (dma_map_sg+0x3c/0x114) > > OK, so this is showing that ARM itself is making the assumption that the > pages are contiguous in the page offset map. > > Fix this by doing the increment via the pfn, which will do the right > thing whatever the memory model. > > Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Ok. What would you like the patch summary line for this to be - the existing one seems to be a little wrong given the content of this patch...
> > --- > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > index 6b2fb87..ab88c5b 100644 > --- a/arch/arm/mm/dma-mapping.c > +++ b/arch/arm/mm/dma-mapping.c > @@ -809,7 +809,7 @@ static void dma_cache_maint_page(struct page *page, unsigned long offset, > op(vaddr, len, dir); > } > offset = 0; > - page++; > + page = pfn_to_page(page_to_pfn(page) + 1); > left -= len; > } while (left); > } > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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