dma-mapping: introduce a dma_common_find_pages helper

A helper to find the backing page array based on a virtual address.
This also ensures we do the same vm_flags check everywhere instead
of slightly different or missing ones in a few places.

Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index fd02c982e36addc0690b0a9fffac2bdbf5cb4102..97bf57df87c1b411c4849e312aac548b232534a1 100644 (file)
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1439,18 +1439,13 @@ static struct page **__atomic_get_pages(void *addr)
 
 static struct page **__iommu_get_pages(void *cpu_addr, unsigned long attrs)
 {
-       struct vm_struct *area;
-
        if (__in_atomic_pool(cpu_addr, PAGE_SIZE))
                return __atomic_get_pages(cpu_addr);
 
        if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)
                return cpu_addr;
 
-       area = find_vm_area(cpu_addr);
-       if (area && (area->flags & VM_DMA_COHERENT))
-               return area->pages;
-       return NULL;
+       return dma_common_find_pages(cpu_addr);
 }
 
 static void *__iommu_alloc_simple(struct device *dev, size_t size, gfp_t gfp,

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 949e341bf2f3d530cfa897f8d6f9891bf46f492f..e8482c57c24e530db7fdadaec55f85bd10300331 100644 (file)
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -541,15 +541,6 @@ static struct page **__iommu_dma_alloc_pages(struct device *dev,
        return pages;
 }
 
-static struct page **__iommu_dma_get_pages(void *cpu_addr)
-{
-       struct vm_struct *area = find_vm_area(cpu_addr);
-
-       if (!area || !area->pages)
-               return NULL;
-       return area->pages;
-}
-
 /**
  * iommu_dma_alloc_remap - Allocate and map a buffer contiguous in IOVA space
  * @dev: Device to allocate memory for. Must be a real device
@@ -938,7 +929,7 @@ static void __iommu_dma_free(struct device *dev, size_t size, void *cpu_addr)
                 * If it the address is remapped, then it's either non-coherent
                 * or highmem CMA, or an iommu_dma_alloc_remap() construction.
                 */
-               pages = __iommu_dma_get_pages(cpu_addr);
+               pages = dma_common_find_pages(cpu_addr);
                if (!pages)
                        page = vmalloc_to_page(cpu_addr);
                dma_common_free_remap(cpu_addr, alloc_size);
@@ -1045,7 +1036,7 @@ static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
                return -ENXIO;
 
        if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) {
-               struct page **pages = __iommu_dma_get_pages(cpu_addr);
+               struct page **pages = dma_common_find_pages(cpu_addr);
 
                if (pages)
                        return __iommu_dma_mmap(pages, size, vma);
@@ -1067,7 +1058,7 @@ static int iommu_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
        int ret;
 
        if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) {
-               struct page **pages = __iommu_dma_get_pages(cpu_addr);
+               struct page **pages = dma_common_find_pages(cpu_addr);
 
                if (pages) {
                        return sg_alloc_table_from_pages(sgt, pages,

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 86223bc24d828206e2a1bdc7158c7e30630a5278..746fa5d6850cf36f19c20458ea3c169996322f77 100644 (file)
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -626,6 +626,7 @@ extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
                void *cpu_addr, dma_addr_t dma_addr, size_t size,
                unsigned long attrs);
 
+struct page **dma_common_find_pages(void *cpu_addr);
 void *dma_common_contiguous_remap(struct page *page, size_t size,
                        pgprot_t prot, const void *caller);
 

diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
index f6b90521a7e423c0206e040529bad74e7aeb8e81..ca4e5d44b5712ddd2b8f4083dac773fa7ed12637 100644 (file)
--- a/kernel/dma/remap.c
+++ b/kernel/dma/remap.c
@@ -11,6 +11,15 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 
+struct page **dma_common_find_pages(void *cpu_addr)
+{
+       struct vm_struct *area = find_vm_area(cpu_addr);
+
+       if (!area || area->flags != VM_DMA_COHERENT)
+               return NULL;
+       return area->pages;
+}
+
 static struct vm_struct *__dma_common_pages_remap(struct page **pages,
                        size_t size, pgprot_t prot, const void *caller)
 {
@@ -78,9 +87,9 @@ void *dma_common_contiguous_remap(struct page *page, size_t size,
  */
 void dma_common_free_remap(void *cpu_addr, size_t size)
 {
-       struct vm_struct *area = find_vm_area(cpu_addr);
+       struct page **pages = dma_common_find_pages(cpu_addr);
 
-       if (!area || area->flags != VM_DMA_COHERENT) {
+       if (!pages) {
                WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
                return;
        }