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

Souptick Joarder
2018-12-08T19:58:05Z

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
>