ARM: dma-mapping: IOMMU allocates pages from atomic_pool with GFP_ATOMIC

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>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 54b158df5afa..051204fc4617 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1161,6 +1161,34 @@ 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)
 {
@@ -1171,6 +1199,9 @@ 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;
@@ -1237,6 +1268,11 @@ 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);