Make use of the same atomic pool as DMA does, and skip a kernel page mapping which can involve sleep'able operations at allocating a kernel page table.
Signed-off-by: Hiroshi Doyu hdoyu@nvidia.com --- arch/arm/mm/dma-mapping.c | 36 ++++++++++++++++++++++++++++++++++++ 1 files changed, 36 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 4ef2d7b..f5024f9 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -1309,6 +1309,34 @@ static struct page **__iommu_get_pages(void *cpu_addr, struct dma_attrs *attrs) return NULL; }
+static void *__iommu_alloc_atomic(struct device *dev, size_t size, + dma_addr_t *handle) +{ + struct page *page; + void *addr; + + addr = __alloc_from_pool(size, &page); + if (!addr) + return NULL; + + *handle = __iommu_create_mapping(dev, &page, size); + if (*handle == DMA_ERROR_CODE) + goto err_mapping; + + return addr; + +err_mapping: + __free_from_pool(addr, size); + return NULL; +} + +static void __iommu_free_atomic(struct device *dev, struct page **pages, + dma_addr_t handle, size_t size) +{ + __iommu_remove_mapping(dev, handle, size); + __free_from_pool(page_address(pages[0]), size); +} + static void *arm_iommu_alloc_attrs(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs) { @@ -1326,6 +1354,9 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size, *handle = DMA_ERROR_CODE; size = PAGE_ALIGN(size);
+ if (gfp & GFP_ATOMIC) + return __iommu_alloc_atomic(dev, size, handle); + pages = __iommu_alloc_buffer(dev, size, gfp); if (!pages) return NULL; @@ -1392,6 +1423,11 @@ void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr, return; }
+ if (__in_atomic_pool(cpu_addr, size)) { + __iommu_free_atomic(dev, pages, handle, size); + return; + } + if (!dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs)) { unmap_kernel_range((unsigned long)cpu_addr, size); vunmap(cpu_addr);