On 2021-11-11 06:50, Christoph Hellwig wrote:
If the architecture can't remap or set an address uncached there is no way to fullfill a request for a coherent allocation. Return NULL in that case. Note that this case currently does not happen, so this is a theoretical fixup and/or a preparation for eventually supporting platforms that can't support coherent allocations with the generic code.
Reviewed-by: Robin Murphy <robin.mur...@arm.com>
Signed-off-by: Christoph Hellwig <h...@lst.de> --- kernel/dma/direct.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index f9658fe18498c..a13017656ecae 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -233,8 +233,9 @@ void *dma_direct_alloc(struct device *dev, size_t size, return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); } else { - if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED)) - set_uncached = true; + if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED)) + return NULL; + set_uncached = true; } }
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