[2/2,Eoan,SRU,Disco] dma-contiguous: page-align the size in dma_free_contiguous()
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Message ID 20190808004314.16433-3-dann.frazier@canonical.com
State New
Headers show
  • Fix regressions introduced by CMA allocation rework
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Commit Message

dann frazier Aug. 8, 2019, 12:43 a.m. UTC
From: Nicolin Chen <nicoleotsuka@gmail.com>

BugLink: https://bugs.launchpad.net/bugs/1839395

According to the original dma_direct_alloc_pages() code:
	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;

	if (!dma_release_from_contiguous(dev, page, count))
		__free_pages(page, get_order(size));

The count parameter for dma_release_from_contiguous() was page
aligned before the right-shifting operation, while the new API
dma_free_contiguous() forgets to have PAGE_ALIGN() at the size.

So this patch simply adds it to prevent any corner case.

Fixes: fdaeec198ada ("dma-contiguous: add dma_{alloc,free}_contiguous() helpers")
Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
(cherry picked from commit f46cc0152501e46d1b3aa5e7eade61145070eab0)
Signed-off-by: dann frazier <dann.frazier@canonical.com>
 kernel/dma/contiguous.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index ea8259f53eda7..2bd410f934b32 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -267,7 +267,8 @@  struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
 void dma_free_contiguous(struct device *dev, struct page *page, size_t size)
-	if (!cma_release(dev_get_cma_area(dev), page, size >> PAGE_SHIFT))
+	if (!cma_release(dev_get_cma_area(dev), page,
+			 PAGE_ALIGN(size) >> PAGE_SHIFT))
 		__free_pages(page, get_order(size));