From 2c7e4a1ac8ec1f908927793e893566aac3dcb9df Mon Sep 17 00:00:00 2001 From: Merlijn Wajer Date: Sun, 12 Dec 2021 02:23:36 +0100 Subject: [PATCH] wip: Revert "dma-direct: Fix potential NULL pointer dereference" This reverts commit f959dcd6ddfd29235030e8026471ac1b022ad2b0. We will need to find a proper fix for this - but it looks like the dma_capable change in include/linux/dma-direct.h makes the ssi code always take the DMA path, which causes various problems. I am not 100% sure that is case, but I have a hunch that pio was always used on the N900 for this. If this is not the case, we'll have figure out what else is required to make DMA work again. --- include/linux/dma-direct.h | 4 ++++ kernel/dma/mapping.c | 9 --------- 2 files changed, 4 insertions(+), 9 deletions(-) diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h index 18aade195884..6eb8f8ae76da 100644 --- a/include/linux/dma-direct.h +++ b/include/linux/dma-direct.h @@ -103,6 +103,10 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size, if (addr == DMA_MAPPING_ERROR) return false; + + if (!dev->dma_mask) + return false; + if (is_ram && !IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) && min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn))) return false; diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 8349a9f2c345..899e6fbb9f40 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -148,9 +148,6 @@ dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page, BUG_ON(!valid_dma_direction(dir)); - if (WARN_ON_ONCE(!dev->dma_mask)) - return DMA_MAPPING_ERROR; - if (dma_map_direct(dev, ops) || arch_dma_map_page_direct(dev, page_to_phys(page) + offset + size)) addr = dma_direct_map_page(dev, page, offset, size, dir, attrs); @@ -185,9 +182,6 @@ static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, BUG_ON(!valid_dma_direction(dir)); - if (WARN_ON_ONCE(!dev->dma_mask)) - return 0; - if (dma_map_direct(dev, ops) || arch_dma_map_sg_direct(dev, sg, nents)) ents = dma_direct_map_sg(dev, sg, nents, dir, attrs); @@ -293,9 +287,6 @@ dma_addr_t dma_map_resource(struct device *dev, phys_addr_t phys_addr, BUG_ON(!valid_dma_direction(dir)); - if (WARN_ON_ONCE(!dev->dma_mask)) - return DMA_MAPPING_ERROR; - /* Don't allow RAM to be mapped */ if (WARN_ON_ONCE(pfn_valid(PHYS_PFN(phys_addr)))) return DMA_MAPPING_ERROR; -- 2.34.1