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Subject[PATCH 11/12] dma-mapping: handle per-device coherent memory mmap in common code
Date
We handle allocation and freeing in common code, so we should handle
mmap the same way. Also all users of per-device coherent memory are
exclusive, that is if we can't allocate from the per-device pool we
can't use the system memory either. Unfold the current
dma_mmap_from_dev_coherent implementation and always use the
per-device pool if it exists.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/arm/mm/dma-mapping-nommu.c | 7 ++--
arch/arm/mm/dma-mapping.c | 3 --
arch/arm64/mm/dma-mapping.c | 3 --
include/linux/dma-mapping.h | 11 ++-----
kernel/dma/coherent.c | 58 ++++++++-------------------------
kernel/dma/internal.h | 2 ++
kernel/dma/mapping.c | 8 ++---
7 files changed, 24 insertions(+), 68 deletions(-)

diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c
index c72f024f1e82..4eeb7e5d9c07 100644
--- a/arch/arm/mm/dma-mapping-nommu.c
+++ b/arch/arm/mm/dma-mapping-nommu.c
@@ -80,11 +80,8 @@ static int arm_nommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
- int ret;
-
- if (dma_mmap_from_global_coherent(vma, cpu_addr, size, &ret))
- return ret;
-
+ if (!(attrs & DMA_ATTR_NON_CONSISTENT))
+ return dma_mmap_from_global_coherent(vma, cpu_addr, size);
return dma_common_mmap(dev, vma, cpu_addr, dma_addr, size, attrs);
}

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 3c8534904209..e2993e5a7166 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -830,9 +830,6 @@ static int __arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
unsigned long pfn = dma_to_pfn(dev, dma_addr);
unsigned long off = vma->vm_pgoff;

- if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
- return ret;
-
if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) {
ret = remap_pfn_range(vma, vma->vm_start,
pfn + off,
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 78c0a72f822c..a55be91c1d1a 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -246,9 +246,6 @@ static int __iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,

vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs);

- if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
- return ret;
-
if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
/*
* DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 018e37a0870e..ae6fe66f97b7 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -158,17 +158,12 @@ static inline int is_device_dma_capable(struct device *dev)
* These three functions are only for dma allocator.
* Don't use them in device drivers.
*/
-int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
- void *cpu_addr, size_t size, int *ret);
-
void *dma_alloc_from_global_coherent(size_t size, dma_addr_t *dma_handle);
void dma_release_from_global_coherent(size_t size, void *vaddr);
int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *cpu_addr,
- size_t size, int *ret);
+ size_t size);

#else
-#define dma_mmap_from_dev_coherent(dev, vma, vaddr, order, ret) (0)
-
static inline void *dma_alloc_from_global_coherent(size_t size,
dma_addr_t *dma_handle)
{
@@ -177,12 +172,10 @@ static inline void *dma_alloc_from_global_coherent(size_t size,

static inline void dma_release_from_global_coherent(size_t size, void *vaddr)
{
- return 0;
}

static inline int dma_mmap_from_global_coherent(struct vm_area_struct *vma,
- void *cpu_addr, size_t size,
- int *ret)
+ void *cpu_addr, size_t size)
{
return 0;
}
diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
index d1da1048e470..d7a27008f228 100644
--- a/kernel/dma/coherent.c
+++ b/kernel/dma/coherent.c
@@ -197,60 +197,30 @@ void dma_release_from_global_coherent(size_t size, void *vaddr)
__dma_release_from_coherent(dma_coherent_default_memory, size, vaddr);
}

-static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
- struct vm_area_struct *vma, void *vaddr, size_t size, int *ret)
+int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
+ struct vm_area_struct *vma, void *vaddr, size_t size)
{
- if (mem && vaddr >= mem->virt_base && vaddr + size <=
- (mem->virt_base + (mem->size << PAGE_SHIFT))) {
- unsigned long off = vma->vm_pgoff;
- int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
- int user_count = vma_pages(vma);
- int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-
- *ret = -ENXIO;
- if (off < count && user_count <= count - off) {
- unsigned long pfn = mem->pfn_base + start + off;
- *ret = remap_pfn_range(vma, vma->vm_start, pfn,
- user_count << PAGE_SHIFT,
- vma->vm_page_prot);
- }
- return 1;
- }
- return 0;
-}
+ unsigned long off = vma->vm_pgoff;
+ int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
+ int user_count = vma_pages(vma);
+ int count = PAGE_ALIGN(size) >> PAGE_SHIFT;

-/**
- * dma_mmap_from_dev_coherent() - mmap memory from the device coherent pool
- * @dev: device from which the memory was allocated
- * @vma: vm_area for the userspace memory
- * @vaddr: cpu address returned by dma_alloc_from_dev_coherent
- * @size: size of the memory buffer allocated
- * @ret: result from remap_pfn_range()
- *
- * This checks whether the memory was allocated from the per-device
- * coherent memory pool and if so, maps that memory to the provided vma.
- *
- * Returns 1 if @vaddr belongs to the device coherent pool and the caller
- * should return @ret, or 0 if they should proceed with mapping memory from
- * generic areas.
- */
-int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
- void *vaddr, size_t size, int *ret)
-{
- struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
-
- return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
+ if (WARN_ON_ONCE(!dma_in_coherent_range(mem, size, vaddr)))
+ return -ENXIO;
+ if (off >= count || user_count > count - off)
+ return -ENXIO;
+ return remap_pfn_range(vma, vma->vm_start, mem->pfn_base + start + off,
+ user_count << PAGE_SHIFT, vma->vm_page_prot);
}
-EXPORT_SYMBOL(dma_mmap_from_dev_coherent);

int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr,
- size_t size, int *ret)
+ size_t size)
{
if (!dma_coherent_default_memory)
return 0;

return __dma_mmap_from_coherent(dma_coherent_default_memory, vma,
- vaddr, size, ret);
+ vaddr, size);
}

/*
diff --git a/kernel/dma/internal.h b/kernel/dma/internal.h
index 48a0a71487b1..651a0991777f 100644
--- a/kernel/dma/internal.h
+++ b/kernel/dma/internal.h
@@ -15,5 +15,7 @@ void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem, size_t size,
dma_addr_t *dma_handle);
void __dma_release_from_coherent(struct dma_coherent_mem *mem, size_t size,
void *vaddr);
+int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
+ struct vm_area_struct *vma, void *vaddr, size_t size);

#endif /* _DMA_INTERNAL_H */
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index d3c4363b2143..5f28dc8f9bf4 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -158,13 +158,9 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned long off = vma->vm_pgoff;
unsigned long pfn;
- int ret = -ENXIO;

vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs);

- if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
- return ret;
-
if (off >= count || user_count > count - off)
return -ENXIO;

@@ -201,6 +197,10 @@ int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
unsigned long attrs)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
+ struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
+
+ if (mem)
+ return __dma_mmap_from_coherent(mem, vma, cpu_addr, size);

if (!dma_is_direct(ops) && ops->mmap)
return ops->mmap(dev, vma, cpu_addr, dma_addr, size, attrs);
--
2.20.1
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