diff options
| author | Christoph Hellwig <hch@lst.de> | 2021-01-28 14:53:22 +0100 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2021-03-15 10:02:31 +0100 |
| commit | eedb0b12d091a21909b5e84d9f3e5e649305bd12 (patch) | |
| tree | 82524abc75941a66dedc9f476cd576eebc7ba225 | |
| parent | 1e28eed17697bcf343c6743f0028cc3b5dd88bf0 (diff) | |
dma-mapping: add a dma_mmap_pages helper
Add a helper to map memory allocated using dma_alloc_pages into
a user address space, similar to the dma_alloc_attrs function for
coherent allocations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Tested-by: Ricardo Ribalda <ribalda@chromium.org>
| -rw-r--r-- | Documentation/core-api/dma-api.rst | 10 | ||||
| -rw-r--r-- | include/linux/dma-mapping.h | 2 | ||||
| -rw-r--r-- | kernel/dma/mapping.c | 13 |
3 files changed, 25 insertions, 0 deletions
diff --git a/Documentation/core-api/dma-api.rst b/Documentation/core-api/dma-api.rst index e6d23f117308..157a474ae544 100644 --- a/Documentation/core-api/dma-api.rst +++ b/Documentation/core-api/dma-api.rst @@ -565,6 +565,16 @@ dma_alloc_pages(). page must be the pointer returned by dma_alloc_pages(). :: + int + dma_mmap_pages(struct device *dev, struct vm_area_struct *vma, + size_t size, struct page *page) + +Map an allocation returned from dma_alloc_pages() into a user address space. +dev and size must be the same as those passed into dma_alloc_pages(). +page must be the pointer returned by dma_alloc_pages(). + +:: + void * dma_alloc_noncoherent(struct device *dev, size_t size, dma_addr_t *dma_handle, enum dma_data_direction dir, diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 2a984cb4d1e0..2b8dce756e1f 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -263,6 +263,8 @@ struct page *dma_alloc_pages(struct device *dev, size_t size, dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp); void dma_free_pages(struct device *dev, size_t size, struct page *page, dma_addr_t dma_handle, enum dma_data_direction dir); +int dma_mmap_pages(struct device *dev, struct vm_area_struct *vma, + size_t size, struct page *page); static inline void *dma_alloc_noncoherent(struct device *dev, size_t size, dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp) diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index b6a633679933..9ce86c77651c 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -517,6 +517,19 @@ void dma_free_pages(struct device *dev, size_t size, struct page *page, } EXPORT_SYMBOL_GPL(dma_free_pages); +int dma_mmap_pages(struct device *dev, struct vm_area_struct *vma, + size_t size, struct page *page) +{ + unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT; + + if (vma->vm_pgoff >= count || vma_pages(vma) > count - vma->vm_pgoff) + return -ENXIO; + return remap_pfn_range(vma, vma->vm_start, + page_to_pfn(page) + vma->vm_pgoff, + vma_pages(vma) << PAGE_SHIFT, vma->vm_page_prot); +} +EXPORT_SYMBOL_GPL(dma_mmap_pages); + int dma_supported(struct device *dev, u64 mask) { const struct dma_map_ops *ops = get_dma_ops(dev); |