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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: b1d2dc009d ("dma-contiguous: add dma_{alloc,free}_contiguous() helpers")
Reported-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de>
This commit is contained in:
Christoph Hellwig 2019-08-20 11:45:49 +09:00
parent 936376f88f
commit 90ae409f9e
4 changed files with 15 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/iommu/dma-iommu.c
View File

@ -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;

5
include/linux/dma-contiguous.h
View File

@ -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,

8
kernel/dma/contiguous.c
View File

@ -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;
}

10
kernel/dma/direct.c
View File

@ -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;