Messages in this thread |  | | Date | Wed, 16 Jan 2013 18:09:14 +0530 | From | Subhash Jadavani <> | Subject | Re: [PATCH v2 1/1] block: blk-merge: don't merge the pages with non-contiguous descriptors |
| |
On 1/16/2013 4:02 PM, 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>
Thanks James. Yes, it make sense to fix the ARM code itself if it is the only one giving this trouble. I have tried your change below and it also fixes this issue (without having my blk-merge patch). I will forward your change to Russel King to see what he thinks about it.
Regards, Subhash > > --- > > 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); > } > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
|  |