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Commit 90ae409f authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-direct: fix zone selection after an unaddressable CMA allocation 



The new dma_alloc_contiguous hides if we allocate CMA or regular
pages, and thus fails to retry a ZONE_NORMAL allocation if the CMA
allocation succeeds but isn't addressable.  That means we either fail
outright or dip into a small zone that might not succeed either.

Thanks to Hillf Danton for debugging this issue.

Fixes: b1d2dc00 ("dma-contiguous: add dma_{alloc,free}_contiguous() helpers")
Reported-by: default avatarTobias Klausmann <tobias.johannes.klausmann@mni.thm.de>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Tested-by: default avatarTobias Klausmann <tobias.johannes.klausmann@mni.thm.de>
parent 936376f8

drivers/iommu/dma-iommu.c

+3 −0
Original line number Diff line number Diff line
@@ -965,10 +965,13 @@ static void *iommu_dma_alloc_pages(struct device *dev, size_t size, 
{

	bool coherent = dev_is_dma_coherent(dev);

	size_t alloc_size = PAGE_ALIGN(size);

	int node = dev_to_node(dev);

	struct page *page = NULL;

	void *cpu_addr;



	page = dma_alloc_contiguous(dev, alloc_size, gfp);

	if (!page)

		page = alloc_pages_node(node, gfp, get_order(alloc_size));

	if (!page)

		return NULL;

include/linux/dma-contiguous.h

+1 −4
Original line number Diff line number Diff line
@@ -160,10 +160,7 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages, 
static inline 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 align = get_order(PAGE_ALIGN(size));



	return alloc_pages_node(node, gfp, align);

	return NULL;

}



static inline void dma_free_contiguous(struct device *dev, struct page *page,

kernel/dma/contiguous.c

+2 −6
Original line number Diff line number Diff line
@@ -230,9 +230,7 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages, 
 */

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 count = size >> PAGE_SHIFT;

	struct page *page = NULL;

	struct cma *cma = NULL;
@@ -243,14 +241,12 @@ 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)) {

		size_t align = get_order(size);

		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 */

	if (!page)

		page = alloc_pages_node(node, gfp, align);

	return page;

}

kernel/dma/direct.c

+9 −1
Original line number Diff line number Diff line
@@ -85,6 +85,8 @@ static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size) 
struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,

		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)

{

	size_t alloc_size = PAGE_ALIGN(size);

	int node = dev_to_node(dev);

	struct page *page = NULL;

	u64 phys_mask;
@@ -95,8 +97,14 @@ struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, 
	gfp &= ~__GFP_ZERO;

	gfp |= __dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,

			&phys_mask);

	page = dma_alloc_contiguous(dev, alloc_size, gfp);

	if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {

		dma_free_contiguous(dev, page, alloc_size);

		page = NULL;

	}

again:

	page = dma_alloc_contiguous(dev, size, gfp);

	if (!page)

		page = alloc_pages_node(node, gfp, get_order(alloc_size));

	if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {

		dma_free_contiguous(dev, page, size);

		page = NULL;