Re: [Xen-devel] [patch 1/2] xen-gntdev: return -EFAULT on copy_to_user failure

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Sat, Mar 19, 2011 at 08:44:34AM +0300, Dan Carpenter wrote:
> copy_to_user() returns the amount of data remaining to be copied.  We
> want to return a negative error code here.  The upper layers just
> call WARN_ON() if we return non-zero so this doesn't change the
> behavior.  But returning -EFAULT is still cleaner.

Thank you. Will put it on rc1 train.
> 
> Signed-off-by: Dan Carpenter <error27@xxxxxxxxx>
> 
> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
> index 017ce60..b0f9e8f 100644
> --- a/drivers/xen/gntdev.c
> +++ b/drivers/xen/gntdev.c
> @@ -273,7 +273,7 @@ static int __unmap_grant_pages(struct grant_map *map, int 
> offset, int pages)
>                               map->vma->vm_start + map->notify.addr;
>                       err = copy_to_user(tmp, &err, 1);
>                       if (err)
> -                             return err;
> +                             return -EFAULT;
>                       map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
>               } else if (pgno >= offset && pgno < offset + pages) {
>                       uint8_t *tmp = kmap(map->pages[pgno]);
> 
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