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From:   Souptick Joarder <jrdr.linux@gmail.com>
Date:   Fri, 25 Jan 2019 11:54:13 +0530
Message-ID: <CAFqt6zZx9qxx_Xv=n-PY45OvS7E8ZBq+ZqaeEKfsaCirwaASSg@mail.gmail.com>
Subject: Re: [PATCH 2/9] arch/arm/mm/dma-mapping.c: Convert to use vm_insert_range
To:     Andrew Morton <akpm@linux-foundation.org>,
        Matthew Wilcox <willy@infradead.org>,
        Michal Hocko <mhocko@suse.com>,
        Russell King - ARM Linux <linux@armlinux.org.uk>,
        robin.murphy@arm.com, iamjoonsoo.kim@lge.com, treding@nvidia.com,
        Kees Cook <keescook@chromium.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>
Cc:     linux-kernel@vger.kernel.org, Linux-MM <linux-mm@kvack.org>,
        linux-arm-kernel@lists.infradead.org
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On Fri, Jan 11, 2019 at 8:33 PM 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>

Any comment on this patch ?

> ---
>  arch/arm/mm/dma-mapping.c | 22 ++++++----------------
>  1 file changed, 6 insertions(+), 16 deletions(-)
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index 78de138..5334391 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -1582,31 +1582,21 @@ 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;
>         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 (vma->vm_pgoff >= nr_pages)
>                 return -ENXIO;
>
> -       pages += off;
> -
> -       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);
> +       err = vm_insert_range(vma, pages, nr_pages);
> +       if (err)
> +               pr_err("Remapping memory failed: %d\n", err);
>
> -       return 0;
> +       return err;
>  }
>  static int arm_iommu_mmap_attrs(struct device *dev,
>                 struct vm_area_struct *vma, void *cpu_addr,
> --
> 1.9.1
>