Re: [PATCH 33/36] tty/vt: consolemap: change refcount only if needed in con_do_clear_unimap()

[Jiri Slaby]

On 07. 06. 22, 17:31, Ilpo Järvinen wrote:
> On Tue, 7 Jun 2022, Jiri Slaby wrote:
>
> > con_do_clear_unimap() currently decreases and increases refcount of old
> > dictionary in a back and forth fashion. This makes the code really hard
> > to follow. Decrease the refcount only if everything went well and we
> > really allocated a new one and decoupled from the old dictionary.
> >
> > I sincerelly hope I did not make a mistake in this (ill) logic.
> >
> > Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
>
> It seems fine:
>
> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
>
> One unrelated comment below for additional cleanup opportunity.
>
> > ---
> >   drivers/tty/vt/consolemap.c | 13 +++++++------
> >   1 file changed, 7 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
> > index 01b7e49f1f91..4d8efe74315c 100644
> > --- a/drivers/tty/vt/consolemap.c
> > +++ b/drivers/tty/vt/consolemap.c
> > @@ -535,22 +535,23 @@ static int con_do_clear_unimap(struct vc_data *vc)
> >   {
> >   	struct uni_pagedict *old = *vc->vc_uni_pagedir_loc;
> >   
> > -	if (!old || --old->refcount) {
> > +	if (!old || old->refcount > 1) {
> >   		struct uni_pagedict *new = kzalloc(sizeof(*new), GFP_KERNEL);
> > -		if (!new) {
> > -			if (old)
> > -				old->refcount++;
> > +		if (!new)
> >   			return -ENOMEM;
> > -		}
> > +
> >   		new->refcount = 1;
> >   		*vc->vc_uni_pagedir_loc = new;
> > +
> > +		if (old)
> > +			old->refcount--;
> >   	} else {
> >   		if (old == dflt)
> >   			dflt = NULL;
>
> This seems unnecessary as con_release_unimap() already does it.

Good point -- the code is real mess... Now, the mess is more apparent, 
at least ;).

I will create a separate patch for this.

thanks,
--
js
suse labs