From 4b85faed211ccfbcc7f3adf1cd62f0b00d1a172b Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 14 Jun 2019 16:06:10 +0200 Subject: [PATCH] dma-mapping: add a dma_alloc_need_uncached helper Check if we need to allocate uncached memory for a device given the allocation flags. Switch over the uncached segment check to this helper to deal with architectures that do not support the dma_cache_sync operation and thus should not returned cacheable memory for DMA_ATTR_NON_CONSISTENT allocations. Signed-off-by: Christoph Hellwig --- include/linux/dma-noncoherent.h | 14 ++++++++++++++ kernel/dma/direct.c | 4 ++-- 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/include/linux/dma-noncoherent.h b/include/linux/dma-noncoherent.h index 7e0126a04e02..732919ac5c11 100644 --- a/include/linux/dma-noncoherent.h +++ b/include/linux/dma-noncoherent.h @@ -20,6 +20,20 @@ static inline bool dev_is_dma_coherent(struct device *dev) } #endif /* CONFIG_ARCH_HAS_DMA_COHERENCE_H */ +/* + * Check if an allocation needs to be marked uncached to be coherent. + */ +static inline bool dma_alloc_need_uncached(struct device *dev, + unsigned long attrs) +{ + if (dev_is_dma_coherent(dev)) + return false; + if (IS_ENABLED(CONFIG_DMA_NONCOHERENT_CACHE_SYNC) && + (attrs & DMA_ATTR_NON_CONSISTENT)) + return false; + return true; +} + void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs); void arch_dma_free(struct device *dev, size_t size, void *cpu_addr, diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index b67f0aa08aa3..c2893713bf80 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -160,7 +160,7 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, memset(ret, 0, size); if (IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) && - !dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_NON_CONSISTENT)) { + dma_alloc_need_uncached(dev, attrs)) { arch_dma_prep_coherent(page, size); ret = uncached_kernel_address(ret); } @@ -182,7 +182,7 @@ void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr, set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order); if (IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) && - !dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_NON_CONSISTENT)) + dma_alloc_need_uncached(dev, attrs)) cpu_addr = cached_kernel_address(cpu_addr); __dma_direct_free_pages(dev, size, virt_to_page(cpu_addr)); }