Re: [PATCH] uio: fix finding mm index for vma

["Hans J. Koch" <hjk@hansjkoch.de>]

On Sun, Mar 27, 2011 at 03:58:19PM +0800, Hillf Danton wrote:

(Added Greg KH to Cc:)

Please Cc: Greg and me when posting patches for UIO.

> When finding mm index for vma it looks more flexible that the mm could
> be sparse, and
> both the size of mm and the pgoff of vma could give correct selection.

Nice improvement!

Thanks for your contribution,
Hans

> 
> Signed-off-by: Hillf Danton <dhillf@gmail.com>

Signed-off-by: Hans J. Koch <hjk@hansjkoch.de>

> ---
> 
> --- a/drivers/uio/uio.c	2011-01-05 08:50:20.000000000 +0800
> +++ b/drivers/uio/uio.c	2011-03-27 14:33:02.000000000 +0800
> @@ -587,14 +587,12 @@ static ssize_t uio_write(struct file *fi
> 
>  static int uio_find_mem_index(struct vm_area_struct *vma)
>  {
> -	int mi;
>  	struct uio_device *idev = vma->vm_private_data;
> 
> -	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
> -		if (idev->info->mem[mi].size == 0)
> +	if (vma->vm_pgoff < MAX_UIO_MAPS) {
> +		if (idev->info->mem[vma->vm_pgoff].size == 0)
>  			return -1;
> -		if (vma->vm_pgoff == mi)
> -			return mi;
> +		return (int)vma->vm_pgoff;
>  	}
>  	return -1;
>  }
> --
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