Re: [PATCH 1/2] dma-pool: fix coherent pool allocations for IOMMU mappings

Nicolas Saenz Julienne
2020-07-28T14:56:34Z

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On Tue, 2020-07-28 at 12:47 +0200, Christoph Hellwig wrote:
> When allocating coherent pool memory for an IOMMU mapping we don't care
> about the DMA mask. Move the guess for the initial GFP mask into the
> dma_direct_alloc_pages and pass dma_coherent_ok as a function pointer
> argument so that it doesn't get applied to the IOMMU case.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> drivers/iommu/dma-iommu.c | 4 +-
> include/linux/dma-direct.h | 3 -
> include/linux/dma-mapping.h | 5 +-
> kernel/dma/direct.c | 13 ++--
> kernel/dma/pool.c | 114 +++++++++++++++---------------------
> 5 files changed, 62 insertions(+), 77 deletions(-)
>

[...]

> -static inline struct gen_pool *dma_get_safer_pool(struct gen_pool *bad_pool)
> +static struct page *__dma_alloc_from_pool(struct device *dev, size_t size,
> + struct gen_pool *pool, void **cpu_addr,
> + bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
> {
> - if (bad_pool == atomic_pool_kernel)
> - return atomic_pool_dma32 ? : atomic_pool_dma;
> + unsigned long addr;
> + phys_addr_t phys;
>
> - if (bad_pool == atomic_pool_dma32)
> - return atomic_pool_dma;
> + addr = gen_pool_alloc(pool, size);
> + if (!addr)
> + return NULL;
>
> - return NULL;
> -}
> + phys = gen_pool_virt_to_phys(pool, addr);
> + if (!phys_addr_ok(dev, phys, size)) {

Shoudn't we check if phys_addr_ok() != NULL?

Regards,
Nicolas

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