Re: [PATCH] mei: expand minor range when registering chrdev region

[cgxu519]

On 2/12/19 5:29 PM, Greg KH wrote:
> On Tue, Feb 12, 2019 at 02:02:52PM +0800, Chengguang Xu wrote:
> > Actually, total amount of available minor number
> > for a single major is MINORMARK + 1. So expand
> > minor range when registering chrdev region.
> >
> > Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx>
> > ---
> >   drivers/misc/mei/main.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
> > index 87281b3695e6..3df54f1e1a8b 100644
> > --- a/drivers/misc/mei/main.c
> > +++ b/drivers/misc/mei/main.c
> > @@ -869,7 +869,7 @@ static const struct file_operations mei_fops = {
> >   
> >   static struct class *mei_class;
> >   static dev_t mei_devt;
> > -#define MEI_MAX_DEVS  MINORMASK
> > +#define MEI_MAX_DEVS  (MINORMASK + 1)
> Why is this needed?  Have you really run out of that many minor nodes
> for this driver?

Not really, practically maybe we cannot reach to the limit.
I was just curious why only one minor number left there and assumed
that was from a mistake(since I've seen similar mistake in other driver).
However, if it explicitly sets to MINORMASK for some reasons, then it's
better to keep as is.

Thanks