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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>
This commit is contained in:
Christoph Hellwig 2019-06-14 16:17:27 +02:00
parent c2f2124e0d
commit d98849aff8
4 changed files with 19 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/xtensa/kernel/pci-dma.c
View File

@ -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

2
include/linux/dma-noncoherent.h
View File

@ -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;

14
kernel/dma/direct.c
View File

@ -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);

13
kernel/dma/remap.c
View File

@ -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));