Hi Marek, Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote @ Tue, 28 Aug 2012 23:58:48 +0200: > Hello, > > On 8/28/2012 1:43 PM, Hiroshi Doyu wrote: > > > Skip cache maint for invalid page but warn it. > > > > Signed-off-by: Hiroshi Doyu <hdoyu@xxxxxxxxxx> > > --- > > arch/arm/mm/dma-mapping.c | 9 +++++++++ > > 1 files changed, 9 insertions(+), 0 deletions(-) > > > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > > index 2621282..0368702 100644 > > --- a/arch/arm/mm/dma-mapping.c > > +++ b/arch/arm/mm/dma-mapping.c > > @@ -1589,6 +1589,9 @@ static void arm_iommu_unmap_page(struct device *dev, dma_addr_t handle, > > if (!iova) > > return; > > > > + if (WARN_ON(!pfn_valid(page_to_pfn(page)))) > > + return; > > + > > if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs)) > > __dma_page_dev_to_cpu(page, offset, size, dir); > > > > @@ -1607,6 +1610,9 @@ static void arm_iommu_sync_single_for_cpu(struct device *dev, > > if (!iova) > > return; > > > > + if (WARN_ON(!pfn_valid(page_to_pfn(page)))) > > + return; > > + > > __dma_page_dev_to_cpu(page, offset, size, dir); > > } > > > > @@ -1621,6 +1627,9 @@ static void arm_iommu_sync_single_for_device(struct device *dev, > > if (!iova) > > return; > > > > + if (WARN_ON(!pfn_valid(page_to_pfn(page)))) > > + return; > > + > > __dma_page_cpu_to_dev(page, offset, size, dir); > > } > > I really wonder what has happened in your system that you require > such paranoid checks. All of the above functions are called on the > scatter-list which has been first passed to dma_map_sg(). IMHO it > makes much more sense to add a pfn_valid() check in dma_map_sg() > and return error if the provided scatter list is not valid instead > of these WARN_ONs. Actually one device driver hit Oops at unmap_page() since this function could be called directly from device drivers, and WARN_ON(dump_stack) helped to find out which device driver did something wrong. IIRC, the following functions can be called directly from device drivers? static inline void dma_unmap_page(struct device *dev, dma_addr_t addr, size_t size, enum dma_data_direction dir); static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size, enum dma_data_direction dir); static inline void dma_sync_single_for_device(struct device *dev, dma_addr_t addr, size_t size, enum dma_data_direction dir); -- 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
