linux-kernel - Re: [PATCH v3 7/9] videobuf2/videobuf2-dma-sg.c: Convert to use vm_insert

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Message-ID: <20181207124851.3eef28a0@coco.lan>
Date:   Fri, 7 Dec 2018 12:48:51 -0200
From:   Mauro Carvalho Chehab <mchehab+samsung@...nel.org>
To:     Souptick Joarder <jrdr.linux@...il.com>
Cc:     akpm@...ux-foundation.org, willy@...radead.org, mhocko@...e.com,
        pawel@...iak.com, m.szyprowski@...sung.com,
        kyungmin.park@...sung.com, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH v3 7/9] videobuf2/videobuf2-dma-sg.c: Convert to use
 vm_insert_range

Em Fri, 7 Dec 2018 00:14:38 +0530
Souptick Joarder <jrdr.linux@...il.com> escreveu:

> 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>

It probably makes sense to apply it via mm tree, together with
patch 1. So:

Acked-by: Mauro Carvalho Chehab <mchehab+samsung@...nel.org>

> ---
>  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.



Thanks,
Mauro