dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code

DMA_ATTR_NO_KERNEL_MAPPING is generally implemented by allocating
normal cacheable pages or CMA memory, and then returning the page
pointer as the opaque handle.  Lift that code from the xtensa and
generic dma remapping implementations into the generic dma-direct
code so that we don't even call arch_dma_alloc for these allocations.

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

diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c
index 9171bff76fc4c6767c905f4cf2a25ef5a74a4fb5..206771277dff68af2ada41d86e5cbe4573b4013d 100644 (file)
--- a/arch/xtensa/kernel/pci-dma.c
+++ b/arch/xtensa/kernel/pci-dma.c
@@ -167,10 +167,6 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 
        *handle = phys_to_dma(dev, page_to_phys(page));
 
-       if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
-               return page;
-       }
-
 #ifdef CONFIG_MMU
        if (PageHighMem(page)) {
                void *p;
@@ -196,9 +192,7 @@ void arch_dma_free(struct device *dev, size_t size, void *vaddr,
        unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
        struct page *page;
 
-       if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
-               page = vaddr;
-       } else if (platform_vaddr_uncached(vaddr)) {
+       if (platform_vaddr_uncached(vaddr)) {
                page = virt_to_page(platform_vaddr_to_cached(vaddr));
        } else {
 #ifdef CONFIG_MMU

diff --git a/include/linux/dma-noncoherent.h b/include/linux/dma-noncoherent.h
index 732919ac5c117830768011be411decc1d871f1b1..53ee36ecdf3749e4df62b741d31f8eaec8dc55d9 100644 (file)
--- a/include/linux/dma-noncoherent.h
+++ b/include/linux/dma-noncoherent.h
@@ -28,6 +28,8 @@ static inline bool dma_alloc_need_uncached(struct device *dev,
 {
        if (dev_is_dma_coherent(dev))
                return false;
+       if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)
+               return false;
        if (IS_ENABLED(CONFIG_DMA_NONCOHERENT_CACHE_SYNC) &&
            (attrs & DMA_ATTR_NON_CONSISTENT))
                return false;

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index fc354f4f490b993e5d61ddf5f3870d34fc4ec0a1..b90e1aede74340942af8ba220a3bf5c7ac51ea27 100644 (file)
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -138,6 +138,14 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
        if (!page)
                return NULL;
 
+       if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
+               /* remove any dirty cache lines on the kernel alias */
+               if (!PageHighMem(page))
+                       arch_dma_prep_coherent(page, size);
+               /* return the page pointer as the opaque cookie */
+               return page;
+       }
+
        if (PageHighMem(page)) {
                /*
                 * Depending on the cma= arguments and per-arch setup
@@ -178,6 +186,12 @@ void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
 {
        unsigned int page_order = get_order(size);
 
+       if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
+               /* cpu_addr is a struct page cookie, not a kernel address */
+               __dma_direct_free_pages(dev, size, cpu_addr);
+               return;
+       }
+
        if (force_dma_unencrypted())
                set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
 

diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
index 0207e3764d52cdeff165fdc9c20e03cb0e9049ee..a594aec07882d9a0ad4d482d00afb81e4daa3189 100644 (file)
--- a/kernel/dma/remap.c
+++ b/kernel/dma/remap.c
@@ -202,8 +202,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 
        size = PAGE_ALIGN(size);
 
-       if (!gfpflags_allow_blocking(flags) &&
-           !(attrs & DMA_ATTR_NO_KERNEL_MAPPING)) {
+       if (!gfpflags_allow_blocking(flags)) {
                ret = dma_alloc_from_pool(size, &page, flags);
                if (!ret)
                        return NULL;
@@ -217,11 +216,6 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
        /* remove any dirty cache lines on the kernel alias */
        arch_dma_prep_coherent(page, size);
 
-       if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
-               ret = page; /* opaque cookie */
-               goto done;
-       }
-
        /* create a coherent mapping */
        ret = dma_common_contiguous_remap(page, size, VM_USERMAP,
                        arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs),
@@ -240,10 +234,7 @@ done:
 void arch_dma_free(struct device *dev, size_t size, void *vaddr,
                dma_addr_t dma_handle, unsigned long attrs)
 {
-       if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
-               /* vaddr is a struct page cookie, not a kernel address */
-               __dma_direct_free_pages(dev, size, vaddr);
-       } else if (!dma_free_from_pool(vaddr, PAGE_ALIGN(size))) {
+       if (!dma_free_from_pool(vaddr, PAGE_ALIGN(size))) {
                phys_addr_t phys = dma_to_phys(dev, dma_handle);
                struct page *page = pfn_to_page(__phys_to_pfn(phys));