linux-kernel - Re: [PATCH 7/9] videobuf2/videobuf2-dma-sg.c: Convert to use vm_insert

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Message-ID: <1c228982-e1c6-a9d5-87ef-1a3206a426f3@samsung.com>
Date:   Wed, 21 Nov 2018 08:54:14 +0100
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     Souptick Joarder <jrdr.linux@...il.com>, akpm@...ux-foundation.org,
        willy@...radead.org, mhocko@...e.com, pawel@...iak.com,
        kyungmin.park@...sung.com, mchehab@...nel.org
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org
Subject: Re: [PATCH 7/9] videobuf2/videobuf2-dma-sg.c: Convert to use
 vm_insert_range

Hi Souptick,

On 2018-11-15 16:50, Souptick Joarder wrote:
> Convert to use vm_insert_range to map range of kernel memory
> to user vma.
>
> Signed-off-by: Souptick Joarder <jrdr.linux@...il.com>
> Reviewed-by: Matthew Wilcox <willy@...radead.org>

Acked-by: Marek Szyprowski <m.szyprowski@...sung.com>

> ---
>  drivers/media/common/videobuf2/videobuf2-dma-sg.c | 23 +++++++----------------
>  1 file changed, 7 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> index 015e737..898adef 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> @@ -328,28 +328,19 @@ static unsigned int vb2_dma_sg_num_users(void *buf_priv)
>  static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
>  {
>  	struct vb2_dma_sg_buf *buf = buf_priv;
> -	unsigned long uaddr = vma->vm_start;
> -	unsigned long usize = vma->vm_end - vma->vm_start;
> -	int i = 0;
> +	unsigned long page_count = vma_pages(vma);
> +	int err;
>  
>  	if (!buf) {
>  		printk(KERN_ERR "No memory to map\n");
>  		return -EINVAL;
>  	}
>  
> -	do {
> -		int ret;
> -
> -		ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
> -		if (ret) {
> -			printk(KERN_ERR "Remapping memory, error: %d\n", ret);
> -			return ret;
> -		}
> -
> -		uaddr += PAGE_SIZE;
> -		usize -= PAGE_SIZE;
> -	} while (usize > 0);
> -
> +	err = vm_insert_range(vma, vma->vm_start, buf->pages, page_count);
> +	if (err) {
> +		printk(KERN_ERR "Remapping memory, error: %d\n", err);
> +		return err;
> +	}
>  
>  	/*
>  	 * Use common vm_area operations to track buffer refcount.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland