From: Nicolin Chen <nicoleotsuka@gmail.com>
To: dafna.hirschfeld@collabora.com, hch@lst.de,
m.szyprowski@samsung.com, robin.murphy@arm.com
Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] dma-contiguous: do not overwrite align in dma_alloc_contiguous()
Date: Thu, 25 Jul 2019 16:39:58 -0700 [thread overview]
Message-ID: <20190725233959.15129-2-nicoleotsuka@gmail.com> (raw)
In-Reply-To: <20190725233959.15129-1-nicoleotsuka@gmail.com>
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 in the fallback routines, 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>
---
kernel/dma/contiguous.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index bfc0c17f2a3d..fa8cd0f0512e 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -233,6 +233,7 @@ struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
int node = dev ? dev_to_node(dev) : NUMA_NO_NODE;
size_t count = PAGE_ALIGN(size) >> PAGE_SHIFT;
size_t align = get_order(PAGE_ALIGN(size));
+ size_t cma_align = CONFIG_CMA_ALIGNMENT;
struct page *page = NULL;
struct cma *cma = NULL;
@@ -241,11 +242,11 @@ struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
else if (count > 1)
cma = dma_contiguous_default_area;
+ cma_align = min_t(size_t, align, cma_align);
+
/* 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);
- }
+ if (cma && gfpflags_allow_blocking(gfp))
+ page = cma_alloc(cma, count, cma_align, gfp & __GFP_NOWARN);
/* Fallback allocation of normal pages */
if (!page)
--
2.17.1
next prev parent reply other threads:[~2019-07-25 23:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 23:39 [PATCH 0/2] dma-contiguous: two bug fixes for dma_{alloc,free}_contiguous() Nicolin Chen
2019-07-25 23:39 ` Nicolin Chen [this message]
2019-07-26 6:28 ` [PATCH 1/2] dma-contiguous: do not overwrite align in dma_alloc_contiguous() Christoph Hellwig
2019-07-26 19:22 ` Nicolin Chen
2019-07-25 23:39 ` [PATCH 2/2] dma-contiguous: page-align the size in dma_free_contiguous() Nicolin Chen
2019-07-26 6:30 ` Christoph Hellwig
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