[PATCH] uio: fix finding mm index for vma

[PATCH] uio: fix finding mm index for vma

[Hillf Danton]

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.

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

--- 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;
 }

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

[Hans J. Koch]

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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