Re: [PATCH] staging: wlan-ng: silence incorrect type in argument 1 (different address spaces) warning

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, Apr 20, 2021 at 02:31:42PM +0530, Ashish Kalra wrote:
> Upon running sparse, "warning: incorrect type in argument 1 (different address spaces)
> is brought to notice for this file.let's add correct typecast to make it cleaner and
> silence the Sparse warning.
> 
> Signed-off-by: Ashish Kalra <eashishkalra@gmail.com>
> ---
>  drivers/staging/wlan-ng/p80211netdev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/wlan-ng/p80211netdev.c b/drivers/staging/wlan-ng/p80211netdev.c
> index 6f9666dc0277..70570e8a5ad2 100644
> --- a/drivers/staging/wlan-ng/p80211netdev.c
> +++ b/drivers/staging/wlan-ng/p80211netdev.c
> @@ -569,7 +569,7 @@ static int p80211knetdev_do_ioctl(struct net_device *dev,
>  		goto bail;
>  	}
>  
> -	msgbuf = memdup_user(req->data, req->len);
> +	msgbuf = memdup_user((void __user *)req->data, req->len);

Why isn't data being declared as a __user pointer to start with?  Why is
the cast needed here?

This feels wrong as if it is papering over the real problem.

thanks,

greg k-h