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dma-mapping: handle vmalloc addresses in dma_common_{mmap,get_sgtable}

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xen-swiotlb can use vmalloc backed addresses for dma coherent allocations
and uses the common helpers.  Properly handle them to unbreak Xen on
ARM platforms.

Fixes: 1b65c4e5a9 ("swiotlb-xen: use xen_alloc/free_coherent_pages")
Signed-off-by: Roman Skakun <roman_skakun@epam.com>
Reviewed-by: Andrii Anisov <andrii_anisov@epam.com>
[hch: split the patch, renamed the helpers]
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Roman Skakun 2021-07-16 11:39:34 +03:00 committed by Christoph Hellwig
parent d936eb2387
commit 40ac971eab
1 changed files with 10 additions and 2 deletions
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12
kernel/dma/ops_helpers.c
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@ -5,6 +5,13 @@
*/
#include <linux/dma-map-ops.h>
static struct page *dma_common_vaddr_to_page(void *cpu_addr)
{
if (is_vmalloc_addr(cpu_addr))
return vmalloc_to_page(cpu_addr);
return virt_to_page(cpu_addr);
}
/*
* Create scatter-list for the already allocated DMA buffer.
*/
@ -12,7 +19,7 @@ int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
struct page *page = virt_to_page(cpu_addr);
struct page *page = dma_common_vaddr_to_page(cpu_addr);
int ret;
ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
@ -32,6 +39,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
unsigned long user_count = vma_pages(vma);
unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned long off = vma->vm_pgoff;
struct page *page = dma_common_vaddr_to_page(cpu_addr);
int ret = -ENXIO;
vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
@ -43,7 +51,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
return -ENXIO;
return remap_pfn_range(vma, vma->vm_start,
page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
page_to_pfn(page) + vma->vm_pgoff,
user_count << PAGE_SHIFT, vma->vm_page_prot);
#else
return -ENXIO;