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SubjectRe: regression in ath10k dma allocation
On Tue, Aug 20, 2019 at 02:58:33PM +0800, Hillf Danton wrote:
>
> On Tue, 20 Aug 2019 05:05:14 +0200 Christoph Hellwig wrote:
> >
> > Tobias, plase try this patch:
> >

New version below:

---
From b8a805e93be5a5662323b8ac61fe686df839c4ac Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Tue, 20 Aug 2019 11:45:49 +0900
Subject: 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: b1d2dc009dec ("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>
---
drivers/iommu/dma-iommu.c | 3 +++
include/linux/dma-contiguous.h | 5 +----
kernel/dma/contiguous.c | 9 +++------
kernel/dma/direct.c | 10 +++++++++-
4 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index d991d40f797f..f68a62c3c32b 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -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;

diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
index c05d4e661489..03f8e98e3bcc 100644
--- a/include/linux/dma-contiguous.h
+++ b/include/linux/dma-contiguous.h
@@ -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,
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 2bd410f934b3..e6b450fdbeb6 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -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;
}

@@ -258,6 +254,7 @@ struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
* dma_free_contiguous() - release allocated pages
* @dev: Pointer to device for which the pages were allocated.
* @page: Pointer to the allocated pages.
+ int node = dev ? dev_to_node(dev) : NUMA_NO_NODE;
* @size: Size of allocated pages.
*
* This function releases memory allocated by dma_alloc_contiguous(). As the
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 795c9b095d75..706113c6bebc 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -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;
--
2.20.1
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