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Subject[patch for-5.8 1/4] dma-direct: always align allocation size in dma_direct_alloc_pages()
dma_alloc_contiguous() does size >> PAGE_SHIFT and set_memory_decrypted()
works at page granularity. It's necessary to page align the allocation
size in dma_direct_alloc_pages() for consistent behavior.

This also fixes an issue when arch_dma_prep_coherent() is called on an
unaligned allocation size for dma_alloc_need_uncached() when
CONFIG_DMA_DIRECT_REMAP is disabled but CONFIG_ARCH_HAS_DMA_SET_UNCACHED
is enabled.

Cc: stable@vger.kernel.org
Signed-off-by: David Rientjes <rientjes@google.com>
---
kernel/dma/direct.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -112,11 +112,12 @@ static inline bool dma_should_free_from_pool(struct device *dev,
struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
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_limit;

+ VM_BUG_ON(!PAGE_ALIGNED(size));
+
if (attrs & DMA_ATTR_NO_WARN)
gfp |= __GFP_NOWARN;

@@ -124,14 +125,14 @@ 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_limit);
- page = dma_alloc_contiguous(dev, alloc_size, gfp);
+ page = dma_alloc_contiguous(dev, size, gfp);
if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
- dma_free_contiguous(dev, page, alloc_size);
+ dma_free_contiguous(dev, page, size);
page = NULL;
}
again:
if (!page)
- page = alloc_pages_node(node, gfp, get_order(alloc_size));
+ page = alloc_pages_node(node, gfp, get_order(size));
if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
dma_free_contiguous(dev, page, size);
page = NULL;
@@ -158,8 +159,10 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
struct page *page;
void *ret;

+ size = PAGE_ALIGN(size);
+
if (dma_should_alloc_from_pool(dev, gfp, attrs)) {
- ret = dma_alloc_from_pool(dev, PAGE_ALIGN(size), &page, gfp);
+ ret = dma_alloc_from_pool(dev, size, &page, gfp);
if (!ret)
return NULL;
goto done;
@@ -183,10 +186,10 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
dma_alloc_need_uncached(dev, attrs)) ||
(IS_ENABLED(CONFIG_DMA_REMAP) && PageHighMem(page))) {
/* remove any dirty cache lines on the kernel alias */
- arch_dma_prep_coherent(page, PAGE_ALIGN(size));
+ arch_dma_prep_coherent(page, size);

/* create a coherent mapping */
- ret = dma_common_contiguous_remap(page, PAGE_ALIGN(size),
+ ret = dma_common_contiguous_remap(page, size,
dma_pgprot(dev, PAGE_KERNEL, attrs),
__builtin_return_address(0));
if (!ret)
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