2018-12-06 18:39:30

by Souptick Joarder

Subject: [PATCH v3 2/9] arch/arm/mm/dma-mapping.c: Convert to use vm_insert_range

Convert to use vm_insert_range() to map range of kernel
memory to user vma.

Signed-off-by: Souptick Joarder <[email protected]>
---
arch/arm/mm/dma-mapping.c | 21 +++++++--------------
1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 661fe48..4eec323 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1582,31 +1582,24 @@ static int __arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
- unsigned long uaddr = vma->vm_start;
- unsigned long usize = vma->vm_end - vma->vm_start;
+ unsigned long page_count = vma_pages(vma);
struct page **pages = __iommu_get_pages(cpu_addr, attrs);
unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned long off = vma->vm_pgoff;
+ int err;

if (!pages)
return -ENXIO;

- if (off >= nr_pages || (usize >> PAGE_SHIFT) > nr_pages - off)
+ if (off >= nr_pages || page_count > nr_pages - off)
return -ENXIO;

pages += off;
+ err = vm_insert_range(vma, vma->vm_start, pages, page_count);
+ if (err)
+ pr_err("Remapping memory failed: %d\n", err);

- do {
- int ret = vm_insert_page(vma, uaddr, *pages++);
- if (ret) {
- pr_err("Remapping memory failed: %d\n", ret);
- return ret;
- }
- uaddr += PAGE_SIZE;
- usize -= PAGE_SIZE;
- } while (usize > 0);
-
- return 0;
+ return err;
}
static int arm_iommu_mmap_attrs(struct device *dev,
struct vm_area_struct *vma, void *cpu_addr,
--
1.9.1

2018-12-08 19:58:55

by Souptick Joarder

Subject: Re: [PATCH v3 2/9] arch/arm/mm/dma-mapping.c: Convert to use vm_insert_range

Hi Robin,

On Fri, Dec 7, 2018 at 12:07 AM Souptick Joarder <[email protected]> wrote:
>
> Convert to use vm_insert_range() to map range of kernel
> memory to user vma.
>
> Signed-off-by: Souptick Joarder <[email protected]>
> ---
> arch/arm/mm/dma-mapping.c | 21 +++++++--------------
> 1 file changed, 7 insertions(+), 14 deletions(-)
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index 661fe48..4eec323 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -1582,31 +1582,24 @@ static int __arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma
> void *cpu_addr, dma_addr_t dma_addr, size_t size,
> unsigned long attrs)
> {
> - unsigned long uaddr = vma->vm_start;
> - unsigned long usize = vma->vm_end - vma->vm_start;
> + unsigned long page_count = vma_pages(vma);
> struct page **pages = __iommu_get_pages(cpu_addr, attrs);
> unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
> unsigned long off = vma->vm_pgoff;
> + int err;
>
> if (!pages)
> return -ENXIO;
>
> - if (off >= nr_pages || (usize >> PAGE_SHIFT) > nr_pages - off)
> + if (off >= nr_pages || page_count > nr_pages - off)
> return -ENXIO;
>
> pages += off;
> + err = vm_insert_range(vma, vma->vm_start, pages, page_count);

Just to clarify, do we need to adjust page_count with vma->vm_pgoff as
original code
have not consider it and run the loop for entire range irrespective of
vma->vm_pgoff value ?

> + if (err)
> + pr_err("Remapping memory failed: %d\n", err);
>
> - do {
> - int ret = vm_insert_page(vma, uaddr, *pages++);
> - if (ret) {
> - pr_err("Remapping memory failed: %d\n", ret);
> - return ret;
> - }
> - uaddr += PAGE_SIZE;
> - usize -= PAGE_SIZE;
> - } while (usize > 0);
> -
> - return 0;
> + return err;
> }
> static int arm_iommu_mmap_attrs(struct device *dev,
> struct vm_area_struct *vma, void *cpu_addr,
> --
> 1.9.1
>

2018-12-10 16:37:34

by Robin Murphy

Subject: Re: [PATCH v3 2/9] arch/arm/mm/dma-mapping.c: Convert to use vm_insert_range

On 08/12/2018 20:01, Souptick Joarder wrote:
> Hi Robin,
>
> On Fri, Dec 7, 2018 at 12:07 AM Souptick Joarder <[email protected]> wrote:
>>
>> Convert to use vm_insert_range() to map range of kernel
>> memory to user vma.
>>
>> Signed-off-by: Souptick Joarder <[email protected]>
>> ---
>> arch/arm/mm/dma-mapping.c | 21 +++++++--------------
>> 1 file changed, 7 insertions(+), 14 deletions(-)
>>
>> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
>> index 661fe48..4eec323 100644
>> --- a/arch/arm/mm/dma-mapping.c
>> +++ b/arch/arm/mm/dma-mapping.c
>> @@ -1582,31 +1582,24 @@ static int __arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma
>> void *cpu_addr, dma_addr_t dma_addr, size_t size,
>> unsigned long attrs)
>> {
>> - unsigned long uaddr = vma->vm_start;
>> - unsigned long usize = vma->vm_end - vma->vm_start;
>> + unsigned long page_count = vma_pages(vma);
>> struct page **pages = __iommu_get_pages(cpu_addr, attrs);
>> unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
>> unsigned long off = vma->vm_pgoff;
>> + int err;
>>
>> if (!pages)
>> return -ENXIO;
>>
>> - if (off >= nr_pages || (usize >> PAGE_SHIFT) > nr_pages - off)
>> + if (off >= nr_pages || page_count > nr_pages - off)
>> return -ENXIO;
>>
>> pages += off;
>> + err = vm_insert_range(vma, vma->vm_start, pages, page_count);
>
> Just to clarify, do we need to adjust page_count with vma->vm_pgoff as
> original code
> have not consider it and run the loop for entire range irrespective of
> vma->vm_pgoff value ?

In this instance, page_count is the size of the VMA, not the size of the
pages array itself, so as I understand things this patch is true to the
original code as-is.

Robin.

>
>> + if (err)
>> + pr_err("Remapping memory failed: %d\n", err);
>>
>> - do {
>> - int ret = vm_insert_page(vma, uaddr, *pages++);
>> - if (ret) {
>> - pr_err("Remapping memory failed: %d\n", ret);
>> - return ret;
>> - }
>> - uaddr += PAGE_SIZE;
>> - usize -= PAGE_SIZE;
>> - } while (usize > 0);
>> -
>> - return 0;
>> + return err;
>> }
>> static int arm_iommu_mmap_attrs(struct device *dev,
>> struct vm_area_struct *vma, void *cpu_addr,
>> --
>> 1.9.1
>>