If CMA is turned on and CMA size is set to zero, kernel should behave as if CMA was not enabled at compile time. Every dma allocation should check existence of cma area before requesting memory.
Arm has done this by commit e464ef16c4f0 ("arm: dma-mapping: add checking cma area initialized"), also do this for arm64. Signed-off-by: Jisheng Zhang <jszh...@marvell.com> --- arch/arm64/mm/dma-mapping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 0bcc4bc..99224dc 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -100,7 +100,7 @@ static void *__dma_alloc_coherent(struct device *dev, size_t size, if (IS_ENABLED(CONFIG_ZONE_DMA) && dev->coherent_dma_mask <= DMA_BIT_MASK(32)) flags |= GFP_DMA; - if (IS_ENABLED(CONFIG_DMA_CMA) && (flags & __GFP_WAIT)) { + if (dev_get_cma_area(dev) && (flags & __GFP_WAIT)) { struct page *page; void *addr; -- 2.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/