Re: [PATCH 1/9] dma-direct: provide page based alloc/free helpers
On Fri, Nov 30, 2018 at 07:04:41PM +, Robin Murphy wrote:
> On 05/11/2018 12:19, Christoph Hellwig wrote:
>> Some architectures support remapping highmem into DMA coherent
>> allocations. To use the common code for them we need variants of
>> dma_direct_{alloc,free}_pages that do not use kernel virtual addresses.
>
> FWIW it's as much about non-cacheable remapping of lowmem as it is about
> highmem. Regardless, the diff looks OK to me.
Yes, but as long as you remap lowmem the current interface work ok,
but once you have highmem a kernel virtual address doesn't cut it,
and we need a page struct or physical address.
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Re: [PATCH 1/9] dma-direct: provide page based alloc/free helpers
On 05/11/2018 12:19, Christoph Hellwig wrote:
Some architectures support remapping highmem into DMA coherent
allocations. To use the common code for them we need variants of
dma_direct_{alloc,free}_pages that do not use kernel virtual addresses.
FWIW it's as much about non-cacheable remapping of lowmem as it is about
highmem. Regardless, the diff looks OK to me.
Reviewed-by: Robin Murphy
Signed-off-by: Christoph Hellwig
---
include/linux/dma-direct.h | 3 +++
kernel/dma/direct.c| 32 ++--
2 files changed, 25 insertions(+), 10 deletions(-)
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index bd73e7a91410..5a7a3bbb912f 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -67,6 +67,9 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs);
void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_addr, unsigned long attrs);
+struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs);
+void __dma_direct_free_pages(struct device *dev, size_t size, struct page
*page);
dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction dir,
unsigned long attrs);
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 22a12ab5a5e9..680287779b0a 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -103,14 +103,13 @@ static bool dma_coherent_ok(struct device *dev,
phys_addr_t phys, size_t size)
min_not_zero(dev->coherent_dma_mask, dev->bus_dma_mask);
}
-void *dma_direct_alloc_pages(struct device *dev, 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)
{
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
int page_order = get_order(size);
struct page *page = NULL;
u64 phys_mask;
- void *ret;
if (attrs & DMA_ATTR_NO_WARN)
gfp |= __GFP_NOWARN;
@@ -150,11 +149,22 @@ void *dma_direct_alloc_pages(struct device *dev, size_t
size,
}
}
+ return page;
+}
+
+void *dma_direct_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
+{
+ struct page *page;
+ void *ret;
+
+ page = __dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs);
if (!page)
return NULL;
+
ret = page_address(page);
if (force_dma_unencrypted()) {
- set_memory_decrypted((unsigned long)ret, 1 << page_order);
+ set_memory_decrypted((unsigned long)ret, 1 << get_order(size));
*dma_handle = __phys_to_dma(dev, page_to_phys(page));
} else {
*dma_handle = phys_to_dma(dev, page_to_phys(page));
@@ -163,20 +173,22 @@ void *dma_direct_alloc_pages(struct device *dev, size_t
size,
return ret;
}
-/*
- * NOTE: this function must never look at the dma_addr argument, because we
want
- * to be able to use it as a helper for iommu implementations as well.
- */
+void __dma_direct_free_pages(struct device *dev, size_t size, struct page
*page)
+{
+ unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+ if (!dma_release_from_contiguous(dev, page, count))
+ __free_pages(page, get_order(size));
+}
+
void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_addr, unsigned long attrs)
{
- unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned int page_order = get_order(size);
if (force_dma_unencrypted())
set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
- if (!dma_release_from_contiguous(dev, virt_to_page(cpu_addr), count))
- free_pages((unsigned long)cpu_addr, page_order);
+ __dma_direct_free_pages(dev, size, virt_to_page(cpu_addr));
}
void *dma_direct_alloc(struct device *dev, size_t size,
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[PATCH 1/9] dma-direct: provide page based alloc/free helpers
Some architectures support remapping highmem into DMA coherent
allocations. To use the common code for them we need variants of
dma_direct_{alloc,free}_pages that do not use kernel virtual addresses.
Signed-off-by: Christoph Hellwig
---
include/linux/dma-direct.h | 3 +++
kernel/dma/direct.c| 32 ++--
2 files changed, 25 insertions(+), 10 deletions(-)
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index bd73e7a91410..5a7a3bbb912f 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -67,6 +67,9 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs);
void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_addr, unsigned long attrs);
+struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs);
+void __dma_direct_free_pages(struct device *dev, size_t size, struct page
*page);
dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction dir,
unsigned long attrs);
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 22a12ab5a5e9..680287779b0a 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -103,14 +103,13 @@ static bool dma_coherent_ok(struct device *dev,
phys_addr_t phys, size_t size)
min_not_zero(dev->coherent_dma_mask, dev->bus_dma_mask);
}
-void *dma_direct_alloc_pages(struct device *dev, 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)
{
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
int page_order = get_order(size);
struct page *page = NULL;
u64 phys_mask;
- void *ret;
if (attrs & DMA_ATTR_NO_WARN)
gfp |= __GFP_NOWARN;
@@ -150,11 +149,22 @@ void *dma_direct_alloc_pages(struct device *dev, size_t
size,
}
}
+ return page;
+}
+
+void *dma_direct_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
+{
+ struct page *page;
+ void *ret;
+
+ page = __dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs);
if (!page)
return NULL;
+
ret = page_address(page);
if (force_dma_unencrypted()) {
- set_memory_decrypted((unsigned long)ret, 1 << page_order);
+ set_memory_decrypted((unsigned long)ret, 1 << get_order(size));
*dma_handle = __phys_to_dma(dev, page_to_phys(page));
} else {
*dma_handle = phys_to_dma(dev, page_to_phys(page));
@@ -163,20 +173,22 @@ void *dma_direct_alloc_pages(struct device *dev, size_t
size,
return ret;
}
-/*
- * NOTE: this function must never look at the dma_addr argument, because we
want
- * to be able to use it as a helper for iommu implementations as well.
- */
+void __dma_direct_free_pages(struct device *dev, size_t size, struct page
*page)
+{
+ unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+ if (!dma_release_from_contiguous(dev, page, count))
+ __free_pages(page, get_order(size));
+}
+
void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_addr, unsigned long attrs)
{
- unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned int page_order = get_order(size);
if (force_dma_unencrypted())
set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
- if (!dma_release_from_contiguous(dev, virt_to_page(cpu_addr), count))
- free_pages((unsigned long)cpu_addr, page_order);
+ __dma_direct_free_pages(dev, size, virt_to_page(cpu_addr));
}
void *dma_direct_alloc(struct device *dev, size_t size,
--
2.19.1
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