5.0-stable review patch. If anyone has any objections, please let me know.
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From: Joerg Roedel jroedel@suse.de
commit 133d624b1cee16906134e92d5befb843b58bcf31 upstream.
The function returns the maximum size that can be mapped using DMA-API functions. The patch also adds the implementation for direct DMA and a new dma_map_ops pointer so that other implementations can expose their limit.
Cc: stable@vger.kernel.org Reviewed-by: Konrad Rzeszutek Wilk konrad.wilk@oracle.com Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- Documentation/DMA-API.txt | 8 ++++++++ include/linux/dma-mapping.h | 8 ++++++++ kernel/dma/direct.c | 11 +++++++++++ kernel/dma/mapping.c | 14 ++++++++++++++ 4 files changed, 41 insertions(+)
--- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -195,6 +195,14 @@ Requesting the required mask does not al wish to take advantage of it, you should issue a dma_set_mask() call to set the mask to the value returned.
+:: + + size_t + dma_direct_max_mapping_size(struct device *dev); + +Returns the maximum size of a mapping for the device. The size parameter +of the mapping functions like dma_map_single(), dma_map_page() and +others should not be larger than the returned value.
Part Id - Streaming DMA mappings -------------------------------- --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -130,6 +130,7 @@ struct dma_map_ops { enum dma_data_direction direction); int (*dma_supported)(struct device *dev, u64 mask); u64 (*get_required_mask)(struct device *dev); + size_t (*max_mapping_size)(struct device *dev); };
#define DMA_MAPPING_ERROR (~(dma_addr_t)0) @@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_fo } #endif
+size_t dma_direct_max_mapping_size(struct device *dev); + #ifdef CONFIG_HAS_DMA #include <asm/dma-mapping.h>
@@ -460,6 +463,7 @@ int dma_supported(struct device *dev, u6 int dma_set_mask(struct device *dev, u64 mask); int dma_set_coherent_mask(struct device *dev, u64 mask); u64 dma_get_required_mask(struct device *dev); +size_t dma_max_mapping_size(struct device *dev); #else /* CONFIG_HAS_DMA */ static inline dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page, size_t offset, size_t size, @@ -561,6 +565,10 @@ static inline u64 dma_get_required_mask( { return 0; } +static inline size_t dma_max_mapping_size(struct device *dev) +{ + return 0; +} #endif /* CONFIG_HAS_DMA */
static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr, --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -380,3 +380,14 @@ int dma_direct_supported(struct device * */ return mask >= __phys_to_dma(dev, min_mask); } + +size_t dma_direct_max_mapping_size(struct device *dev) +{ + size_t size = SIZE_MAX; + + /* If SWIOTLB is active, use its maximum mapping size */ + if (is_swiotlb_active()) + size = swiotlb_max_mapping_size(dev); + + return size; +} --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -357,3 +357,17 @@ void dma_cache_sync(struct device *dev, ops->cache_sync(dev, vaddr, size, dir); } EXPORT_SYMBOL(dma_cache_sync); + +size_t dma_max_mapping_size(struct device *dev) +{ + const struct dma_map_ops *ops = get_dma_ops(dev); + size_t size = SIZE_MAX; + + if (dma_is_direct(ops)) + size = dma_direct_max_mapping_size(dev); + else if (ops && ops->max_mapping_size) + size = ops->max_mapping_size(dev); + + return size; +} +EXPORT_SYMBOL_GPL(dma_max_mapping_size);