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

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Submitter Souptick Joarder
Date Dec. 6, 2018, 6:41 p.m.
Message ID <20181206184103.GA25872@jordon-HP-15-Notebook-PC>
Download mbox | patch
Permalink /patch/674537/
State New
Headers show

Comments

Souptick Joarder - Dec. 6, 2018, 6:41 p.m.
Convert to use vm_insert_range() to map range of kernel
memory to user vma.

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
---
 arch/arm/mm/dma-mapping.c | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)
Souptick Joarder - Dec. 8, 2018, 8:01 p.m.
Hi Robin,

On Fri, Dec 7, 2018 at 12:07 AM Souptick Joarder <jrdr.linux@gmail.com> wrote:
>
> Convert to use vm_insert_range() to map range of kernel
> memory to user vma.
>
> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
> ---
>  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
>
Robin Murphy - Dec. 10, 2018, 4:32 p.m.
On 08/12/2018 20:01, Souptick Joarder wrote:
> Hi Robin,
> 
> On Fri, Dec 7, 2018 at 12:07 AM Souptick Joarder <jrdr.linux@gmail.com> wrote:
>>
>> Convert to use vm_insert_range() to map range of kernel
>> memory to user vma.
>>
>> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
>> ---
>>   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
>>

Patch

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,