Re:?==?utf-8?q? [PATCH]?==?utf-8?q? um: ubd: fix command line handling of ubd

[Christopher Obbard]

Hi Hajime,

Doh! Thanks for sorting out this regression!
 
On Monday, 21 December, 2020 02:24 GMT, Hajime Tazaki <thehajime at gmail.com> wrote: 
> This commit fixes a regression to handle command line parameters of ubd.
> With a simple line "./linux ubd0="./disk-ext4.img", it fails at
> ubd_setup_common().  The commit adds additional checks to the variables
> in order to properly parse the paremeters which previously worked.
> 
> Fixes: ef3ba87cb7c9 ("um: ubd: Set device serial attribute from
> cmdline")
> Cc: Christopher Obbard <chris.obbard at collabora.com>
> Signed-off-by: Hajime Tazaki <thehajime at gmail.com>

Acked-by: Christopher Obbard <chris.obbard at collabora.com>

> ---
>  arch/um/drivers/ubd_kern.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
> index 13b1fe694b90..bd16b17ba4d6 100644
> --- a/arch/um/drivers/ubd_kern.c
> +++ b/arch/um/drivers/ubd_kern.c
> @@ -375,11 +375,11 @@ static int ubd_setup_common(char *str, int *index_out, char **error_out)
>  		file = NULL;
>  
>  	backing_file = strsep(&str, ",:");
> -	if (*backing_file == '\0')
> +	if (backing_file && *backing_file == '\0')
>  		backing_file = NULL;
>  
>  	serial = strsep(&str, ",:");
> -	if (*serial == '\0')
> +	if (serial && *serial == '\0')
>  		serial = NULL;
>  
>  	if (backing_file && ubd_dev->no_cow) {
> -- 
> 2.17.2
>