dma-direct: provide function to check physical memory area validity

dma_coherent_ok() checks if a physical memory area fits a device's DMA
constraints.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index 5184735a0fe8eb93dbd3dbbebdad8a92eb0affad..ab2e20cba9514be7b37952bafa1c93b4bd37b11d 100644 (file)
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -69,6 +69,7 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size,
 u64 dma_direct_get_required_mask(struct device *dev);
 gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
                                  u64 *phys_mask);
+bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size);
 void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
                gfp_t gfp, unsigned long attrs);
 void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 95866b647581007862dc39af279a350edcfa13be..67f060b86a73fa0ee8be935ef6dc4e60b9247f2a 100644 (file)
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -70,7 +70,7 @@ gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
        return 0;
 }
 
-static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
+bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
 {
        return phys_to_dma_direct(dev, phys) + size - 1 <=
                        min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);