ARM DMA: Fix in dma_cache_maint_page
From: Subhash Jadavani <hidden>
Date: 2013-01-16 12:47:08
Also in:
linux-arm-msm
Hi Russell, Is it possible to pick up James patch below? Thread here: http://comments.gmane.org/gmane.linux.kernel.mmc/18670, have the details on the motivation behind this fix. Regards, Subhash -------- Original Message -------- Subject: Re: [PATCH v2 1/1] block: blk-merge: don't merge the pages with non-contiguous descriptors Date: Wed, 16 Jan 2013 18:09:14 +0530 From: Subhash Jadavani <redacted> To: James Bottomley <James.Bottomley@HansenPartnership.com> CC: linux-kernel at vger.kernel.org, linux-scsi at vger.kernel.org, linux-mmc at vger.kernel.org, linux-arm-msm at vger.kernel.org, martin.petersen at oracle.com, asias at redhat.com, tj at kernel.org, linux-arm-kernel at lists.infradead.org, Russell King [off-list ref] On 1/16/2013 4:02 PM, James Bottomley wrote:
On Wed, 2013-01-16 at 12:07 +0530, Subhash Jadavani wrote:quoted
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 <redacted>
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
quoted hunk ↗ jump to hunk
---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 at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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