| Message ID | 1415636045-24669-8-git-send-email-stefano.stabellini@eu.citrix.com |
|---|---|
| State | New |
| Headers | show |
On Mon, Nov 10, 2014 at 04:14:00PM +0000, Stefano Stabellini wrote: > In xen_dma_map_page, if the page is a local page, call the native > map_page dma_ops. If the page is foreign, call __xen_dma_map_page that > issues any required cache maintenane operations via hypercall. > > The reason for doing this is that the native dma_ops map_page could > allocate buffers than need to be freed. If the page is foreign we don't > call the native unmap_page dma_ops function, resulting in a memory leak. > > Suggested-by: Catalin Marinas <catalin.marinas@arm.com> > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > --- > arch/arm/include/asm/xen/page-coherent.h | 9 ++++++++- > arch/arm/xen/mm32.c | 12 ++++++++++++ > 2 files changed, 20 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/include/asm/xen/page-coherent.h b/arch/arm/include/asm/xen/page-coherent.h > index 25d450c..36b79a8 100644 > --- a/arch/arm/include/asm/xen/page-coherent.h > +++ b/arch/arm/include/asm/xen/page-coherent.h > @@ -5,6 +5,9 @@ > #include <linux/dma-attrs.h> > #include <linux/dma-mapping.h> > > +void __xen_dma_map_page(struct device *hwdev, struct page *page, > + dma_addr_t dev_addr, unsigned long offset, size_t size, > + enum dma_data_direction dir, struct dma_attrs *attrs); > void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle, > size_t size, enum dma_data_direction dir, > struct dma_attrs *attrs); > @@ -32,7 +35,11 @@ static inline void xen_dma_map_page(struct device *hwdev, struct page *page, > dma_addr_t dev_addr, unsigned long offset, size_t size, > enum dma_data_direction dir, struct dma_attrs *attrs) > { > - __generic_dma_ops(hwdev)->map_page(hwdev, page, offset, size, dir, attrs); > + if (PFN_DOWN(dev_addr) == page_to_pfn(page)) { Nitpick: you could write: bool foreign = PFN_DOWN(dev_addr) == page_to_pfn(page); or even a static inline xen_foreign_page(page, dev_addr) function for clarity. This code lacks comments. > + if (__generic_dma_ops(hwdev)->map_page) I'm not sure we need to check map_page() here. I thought it's always present as host DMA API does not check for it.
diff --git a/arch/arm/include/asm/xen/page-coherent.h b/arch/arm/include/asm/xen/page-coherent.h index 25d450c..36b79a8 100644 --- a/arch/arm/include/asm/xen/page-coherent.h +++ b/arch/arm/include/asm/xen/page-coherent.h @@ -5,6 +5,9 @@ #include <linux/dma-attrs.h> #include <linux/dma-mapping.h> +void __xen_dma_map_page(struct device *hwdev, struct page *page, + dma_addr_t dev_addr, unsigned long offset, size_t size, + enum dma_data_direction dir, struct dma_attrs *attrs); void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle, size_t size, enum dma_data_direction dir, struct dma_attrs *attrs); @@ -32,7 +35,11 @@ static inline void xen_dma_map_page(struct device *hwdev, struct page *page, dma_addr_t dev_addr, unsigned long offset, size_t size, enum dma_data_direction dir, struct dma_attrs *attrs) { - __generic_dma_ops(hwdev)->map_page(hwdev, page, offset, size, dir, attrs); + if (PFN_DOWN(dev_addr) == page_to_pfn(page)) { + if (__generic_dma_ops(hwdev)->map_page) + __generic_dma_ops(hwdev)->map_page(hwdev, page, offset, size, dir, attrs); + } else + __xen_dma_map_page(hwdev, page, dev_addr, offset, size, dir, attrs); } void xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle, diff --git a/arch/arm/xen/mm32.c b/arch/arm/xen/mm32.c index 7824498..d611c4b 100644 --- a/arch/arm/xen/mm32.c +++ b/arch/arm/xen/mm32.c @@ -45,6 +45,18 @@ static void __xen_dma_page_cpu_to_dev(struct device *hwdev, dma_addr_t handle, dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_MAP); } +void __xen_dma_map_page(struct device *hwdev, struct page *page, + dma_addr_t dev_addr, unsigned long offset, size_t size, + enum dma_data_direction dir, struct dma_attrs *attrs) +{ + if (is_device_dma_coherent(hwdev)) + return; + if (dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs)) + return; + + __xen_dma_page_cpu_to_dev(hwdev, dev_addr, size, dir); +} + void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle, size_t size, enum dma_data_direction dir, struct dma_attrs *attrs)
In xen_dma_map_page, if the page is a local page, call the native map_page dma_ops. If the page is foreign, call __xen_dma_map_page that issues any required cache maintenane operations via hypercall. The reason for doing this is that the native dma_ops map_page could allocate buffers than need to be freed. If the page is foreign we don't call the native unmap_page dma_ops function, resulting in a memory leak. Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> --- arch/arm/include/asm/xen/page-coherent.h | 9 ++++++++- arch/arm/xen/mm32.c | 12 ++++++++++++ 2 files changed, 20 insertions(+), 1 deletion(-)