From d01501f85249848a2497968d46dd46d5c6fe32e6 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Thu, 1 Nov 2018 07:54:24 +0000 Subject: [PATCH] MIPS: Fix `dma_alloc_coherent' returning a non-coherent allocation Fix a MIPS `dma_alloc_coherent' regression from commit bc3ec75de545 ("dma-mapping: merge direct and noncoherent ops") that causes a cached allocation to be returned on noncoherent cache systems. This is due to an inverted check now used in the MIPS implementation of `arch_dma_alloc' on the result from `dma_direct_alloc_pages' before doing the cached-to-uncached mapping of the allocation address obtained. The mapping has to be done for a non-NULL rather than NULL result, because a NULL result means the allocation has failed. Invert the check for correct operation then. Signed-off-by: Maciej W. Rozycki Signed-off-by: Paul Burton Reviewed-by: Christoph Hellwig Fixes: bc3ec75de545 ("dma-mapping: merge direct and noncoherent ops") Patchwork: https://patchwork.linux-mips.org/patch/20965/ --- arch/mips/mm/dma-noncoherent.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/mm/dma-noncoherent.c b/arch/mips/mm/dma-noncoherent.c index e6c9485cadcf..cb38461391cb 100644 --- a/arch/mips/mm/dma-noncoherent.c +++ b/arch/mips/mm/dma-noncoherent.c @@ -50,7 +50,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, void *ret; ret = dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs); - if (!ret && !(attrs & DMA_ATTR_NON_CONSISTENT)) { + if (ret && !(attrs & DMA_ATTR_NON_CONSISTENT)) { dma_cache_wback_inv((unsigned long) ret, size); ret = (void *)UNCAC_ADDR(ret); }