Commit c6622a42 authored Jul 26, 2019 by Nicolin Chen Committed by Christoph Hellwig Jul 29, 2019

dma-contiguous: do not overwrite align in dma_alloc_contiguous()



The dma_alloc_contiguous() limits align at CONFIG_CMA_ALIGNMENT for
cma_alloc() however it does not restore it for the fallback routine.
This will result in a size mismatch between the allocation and free
when running into the fallback routines after cma_alloc() fails, if
the align is larger than CONFIG_CMA_ALIGNMENT.

This patch adds a cma_align to take care of cma_alloc() and prevent
the align from being overwritten.

Fixes: fdaeec198ada ("dma-contiguous: add dma_{alloc,free}_contiguous() helpers")
Reported-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

parent 609488bc

kernel/dma/contiguous.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -243,8 +243,9 @@ struct page dma_alloc_contiguous(struct device dev, size_t size, gfp_t gfp)

		/* CMA can be used only in the context which permits sleeping */
		if (cma && gfpflags_allow_blocking(gfp)) {
		align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT);
		page = cma_alloc(cma, count, align, gfp & __GFP_NOWARN);
		size_t cma_align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT);

		page = cma_alloc(cma, count, cma_align, gfp & __GFP_NOWARN);
		}

		/* Fallback allocation of normal pages */

Admin message