[PATCH 2/4] dma-mapping: always use VM_DMA_COHERENT for generic DMA remap

From: Christoph Hellwig
Date: Fri Aug 30 2019 - 02:29:46 EST


Currently the generic dma remap allocator gets a vm_flags passed by
the caller that is a little confusing. We just introduced a generic
vmalloc-level flag to identify the dma coherent allocations, so use
that everywhere and remove the now pointless argument.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
arch/arm/mm/dma-mapping.c | 10 ++++------
arch/xtensa/kernel/pci-dma.c | 4 ++--
drivers/iommu/dma-iommu.c | 6 +++---
include/linux/dma-mapping.h | 6 ++----
kernel/dma/remap.c | 25 +++++++++++--------------
5 files changed, 22 insertions(+), 29 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 5c0af4a2faa7..054a66f725b3 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -340,13 +340,12 @@ static void *
__dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
const void *caller)
{
- return dma_common_contiguous_remap(page, size, VM_DMA_COHERENT,
- prot, caller);
+ return dma_common_contiguous_remap(page, size, prot, caller);
}

static void __dma_free_remap(void *cpu_addr, size_t size)
{
- dma_common_free_remap(cpu_addr, size, VM_DMA_COHERENT);
+ dma_common_free_remap(cpu_addr, size);
}

#define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K
@@ -1373,8 +1372,7 @@ static void *
__iommu_alloc_remap(struct page **pages, size_t size, gfp_t gfp, pgprot_t prot,
const void *caller)
{
- return dma_common_pages_remap(pages, size, VM_DMA_COHERENT, prot,
- caller);
+ return dma_common_pages_remap(pages, size, prot, caller);
}

/*
@@ -1617,7 +1615,7 @@ void __arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
}

if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0)
- dma_common_free_remap(cpu_addr, size, VM_DMA_COHERENT);
+ dma_common_free_remap(cpu_addr, size);

__iommu_remove_mapping(dev, handle, size);
__iommu_free_buffer(dev, pages, size, attrs);
diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c
index 65f05776d827..154979d62b73 100644
--- a/arch/xtensa/kernel/pci-dma.c
+++ b/arch/xtensa/kernel/pci-dma.c
@@ -167,7 +167,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
if (PageHighMem(page)) {
void *p;

- p = dma_common_contiguous_remap(page, size, VM_MAP,
+ p = dma_common_contiguous_remap(page, size,
pgprot_noncached(PAGE_KERNEL),
__builtin_return_address(0));
if (!p) {
@@ -192,7 +192,7 @@ void arch_dma_free(struct device *dev, size_t size, void *vaddr,
page = virt_to_page(platform_vaddr_to_cached(vaddr));
} else {
#ifdef CONFIG_MMU
- dma_common_free_remap(vaddr, size, VM_MAP);
+ dma_common_free_remap(vaddr, size);
#endif
page = pfn_to_page(PHYS_PFN(dma_to_phys(dev, dma_handle)));
}
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index f68a62c3c32b..013416f5ad38 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -617,7 +617,7 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
< size)
goto out_free_sg;

- vaddr = dma_common_pages_remap(pages, size, VM_USERMAP, prot,
+ vaddr = dma_common_pages_remap(pages, size, prot,
__builtin_return_address(0));
if (!vaddr)
goto out_unmap;
@@ -941,7 +941,7 @@ static void __iommu_dma_free(struct device *dev, size_t size, void *cpu_addr)
pages = __iommu_dma_get_pages(cpu_addr);
if (!pages)
page = vmalloc_to_page(cpu_addr);
- dma_common_free_remap(cpu_addr, alloc_size, VM_USERMAP);
+ dma_common_free_remap(cpu_addr, alloc_size);
} else {
/* Lowmem means a coherent atomic or CMA allocation */
page = virt_to_page(cpu_addr);
@@ -979,7 +979,7 @@ static void *iommu_dma_alloc_pages(struct device *dev, size_t size,
pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs);

cpu_addr = dma_common_contiguous_remap(page, alloc_size,
- VM_USERMAP, prot, __builtin_return_address(0));
+ prot, __builtin_return_address(0));
if (!cpu_addr)
goto out_free_pages;

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index f7d1eea32c78..c9725390fbbc 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -616,13 +616,11 @@ extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
unsigned long attrs);

void *dma_common_contiguous_remap(struct page *page, size_t size,
- unsigned long vm_flags,
pgprot_t prot, const void *caller);

void *dma_common_pages_remap(struct page **pages, size_t size,
- unsigned long vm_flags, pgprot_t prot,
- const void *caller);
-void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags);
+ pgprot_t prot, const void *caller);
+void dma_common_free_remap(void *cpu_addr, size_t size);

int __init dma_atomic_pool_init(gfp_t gfp, pgprot_t prot);
bool dma_in_atomic_pool(void *start, size_t size);
diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
index ffe78f0b2fe4..01d4ef5685a4 100644
--- a/kernel/dma/remap.c
+++ b/kernel/dma/remap.c
@@ -12,12 +12,11 @@
#include <linux/vmalloc.h>

static struct vm_struct *__dma_common_pages_remap(struct page **pages,
- size_t size, unsigned long vm_flags, pgprot_t prot,
- const void *caller)
+ size_t size, pgprot_t prot, const void *caller)
{
struct vm_struct *area;

- area = get_vm_area_caller(size, vm_flags, caller);
+ area = get_vm_area_caller(size, VM_DMA_COHERENT, caller);
if (!area)
return NULL;

@@ -34,12 +33,11 @@ static struct vm_struct *__dma_common_pages_remap(struct page **pages,
* Cannot be used in non-sleeping contexts
*/
void *dma_common_pages_remap(struct page **pages, size_t size,
- unsigned long vm_flags, pgprot_t prot,
- const void *caller)
+ pgprot_t prot, const void *caller)
{
struct vm_struct *area;

- area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
+ area = __dma_common_pages_remap(pages, size, prot, caller);
if (!area)
return NULL;

@@ -53,7 +51,6 @@ void *dma_common_pages_remap(struct page **pages, size_t size,
* Cannot be used in non-sleeping contexts
*/
void *dma_common_contiguous_remap(struct page *page, size_t size,
- unsigned long vm_flags,
pgprot_t prot, const void *caller)
{
int i;
@@ -67,7 +64,7 @@ void *dma_common_contiguous_remap(struct page *page, size_t size,
for (i = 0; i < (size >> PAGE_SHIFT); i++)
pages[i] = nth_page(page, i);

- area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
+ area = __dma_common_pages_remap(pages, size, prot, caller);

kfree(pages);

@@ -79,11 +76,11 @@ void *dma_common_contiguous_remap(struct page *page, size_t size,
/*
* Unmaps a range previously mapped by dma_common_*_remap
*/
-void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
+void dma_common_free_remap(void *cpu_addr, size_t size)
{
struct vm_struct *area = find_vm_area(cpu_addr);

- if (!area || (area->flags & vm_flags) != vm_flags) {
+ if (!area || area->flags != VM_DMA_COHERENT) {
WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
return;
}
@@ -127,8 +124,8 @@ int __init dma_atomic_pool_init(gfp_t gfp, pgprot_t prot)
if (!atomic_pool)
goto free_page;

- addr = dma_common_contiguous_remap(page, atomic_pool_size, VM_USERMAP,
- prot, __builtin_return_address(0));
+ addr = dma_common_contiguous_remap(page, atomic_pool_size, prot,
+ __builtin_return_address(0));
if (!addr)
goto destroy_genpool;

@@ -143,7 +140,7 @@ int __init dma_atomic_pool_init(gfp_t gfp, pgprot_t prot)
return 0;

remove_mapping:
- dma_common_free_remap(addr, atomic_pool_size, VM_USERMAP);
+ dma_common_free_remap(addr, atomic_pool_size);
destroy_genpool:
gen_pool_destroy(atomic_pool);
atomic_pool = NULL;
@@ -217,7 +214,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
arch_dma_prep_coherent(page, size);

/* create a coherent mapping */
- ret = dma_common_contiguous_remap(page, size, VM_USERMAP,
+ ret = dma_common_contiguous_remap(page, size,
dma_pgprot(dev, PAGE_KERNEL, attrs),
__builtin_return_address(0));
if (!ret) {
--
2.20.1