dma-pool: introduce dma_guess_pool()
dma-pool's dev_to_pool() creates the false impression that there is a way to grantee a mapping between a device's DMA constraints and an atomic pool. It tuns out it's just a guess, and the device might need to use an atomic pool containing memory from a 'safer' (or lower) memory zone. To help mitigate this, introduce dma_guess_pool() which can be fed a device's DMA constraints and atomic pools already known to be faulty, in order for it to provide an better guess on which pool to use. Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
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23e469be62
Коммит
48b6703858
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@ -203,7 +203,7 @@ static int __init dma_atomic_pool_init(void)
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}
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postcore_initcall(dma_atomic_pool_init);
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static inline struct gen_pool *dev_to_pool(struct device *dev)
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static inline struct gen_pool *dma_guess_pool_from_device(struct device *dev)
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{
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u64 phys_mask;
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gfp_t gfp;
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@ -217,10 +217,30 @@ static inline struct gen_pool *dev_to_pool(struct device *dev)
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return atomic_pool_kernel;
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}
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static inline struct gen_pool *dma_get_safer_pool(struct gen_pool *bad_pool)
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{
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if (bad_pool == atomic_pool_kernel)
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return atomic_pool_dma32 ? : atomic_pool_dma;
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if (bad_pool == atomic_pool_dma32)
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return atomic_pool_dma;
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return NULL;
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}
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static inline struct gen_pool *dma_guess_pool(struct device *dev,
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struct gen_pool *bad_pool)
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{
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if (bad_pool)
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return dma_get_safer_pool(bad_pool);
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return dma_guess_pool_from_device(dev);
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}
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void *dma_alloc_from_pool(struct device *dev, size_t size,
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struct page **ret_page, gfp_t flags)
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{
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struct gen_pool *pool = dev_to_pool(dev);
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struct gen_pool *pool = dma_guess_pool(dev, NULL);
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unsigned long val;
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void *ptr = NULL;
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@ -249,7 +269,7 @@ void *dma_alloc_from_pool(struct device *dev, size_t size,
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bool dma_free_from_pool(struct device *dev, void *start, size_t size)
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{
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struct gen_pool *pool = dev_to_pool(dev);
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struct gen_pool *pool = dma_guess_pool(dev, NULL);
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if (!pool || !gen_pool_has_addr(pool, (unsigned long)start, size))
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return false;
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