| Message ID | 1358332355.2384.11.camel@dabdike.int.hansenpartnership.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Jan 16, 2013 at 10:32:35AM +0000, James Bottomley wrote: > 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); Probably page = nth_page(page, 1) is the better form. Thanks.
On Wed, 2013-01-16 at 23:14 +0000, Russell King - ARM Linux wrote: > 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... how about arm: fix struct page iterator in dma_cache_maint() to work with sparsemem ? James > > > > --- > > > > 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 > -- > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 2013-01-16 at 15:18 -0800, Tejun Heo wrote: > On Wed, Jan 16, 2013 at 10:32:35AM +0000, James Bottomley wrote: > > 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); > > Probably page = nth_page(page, 1) is the better form. It's the same thing. I'd actually prefer page = pfn_to_page(page_to_pfn(page) + 1); because it makes the code look like the hack it is. The preferred form for all iterators like this should be to iterate over the pfn instead of a pointer into the page arrays, because that will always work correctly no matter how many weird and wonderful memory schemes we come up with. James -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jan 17, 2013 at 09:11:20AM +0000, James Bottomley wrote: > On Wed, 2013-01-16 at 15:18 -0800, Tejun Heo wrote: > > On Wed, Jan 16, 2013 at 10:32:35AM +0000, James Bottomley wrote: > > > 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); > > > > Probably page = nth_page(page, 1) is the better form. > > It's the same thing. > > I'd actually prefer page = pfn_to_page(page_to_pfn(page) + 1); because > it makes the code look like the hack it is. The preferred form for all > iterators like this should be to iterate over the pfn instead of a > pointer into the page arrays, because that will always work correctly no > matter how many weird and wonderful memory schemes we come up with. So, why don't we update the code to do that then? -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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); }