linux-kernel - Re: [PATCH v2 04/17] thermal: core: Clean up cdev binding/unbinding functions

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Message-ID: <CAJZ5v0gyc73QpMHPiYdm0nKMJtrGg25-C=8Ytamt91rSS=0ONQ@mail.gmail.com>
Date: Tue, 13 Aug 2024 12:54:47 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: "Zhang, Rui" <rui.zhang@...el.com>
Cc: "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>, "rjw@...ysocki.net" <rjw@...ysocki.net>, 
	"lukasz.luba@....com" <lukasz.luba@....com>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, 
	"daniel.lezcano@...aro.org" <daniel.lezcano@...aro.org>
Subject: Re: [PATCH v2 04/17] thermal: core: Clean up cdev binding/unbinding functions

On Tue, Aug 13, 2024 at 9:39 AM Zhang, Rui <rui.zhang@...el.com> wrote:
>
> On Mon, 2024-08-12 at 15:56 +0200, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> >
> > Add a new label to thermal_bind_cdev_to_trip() and use it to
> > eliminate
> > two redundant !result check from that function, rename a label in
> > thermal_unbind_cdev_from_trip() to reflect its actual purpose and
> > adjust some white space in these functions.
> >
> > No intentional functional impact.
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > ---
> >
> > v1 -> v2: No changes.
> >
> > ---
> >  drivers/thermal/thermal_core.c |   32 ++++++++++++++++++------------
> > --
> >  1 file changed, 18 insertions(+), 14 deletions(-)
> >
> > Index: linux-pm/drivers/thermal/thermal_core.c
> > ===================================================================
> > --- linux-pm.orig/drivers/thermal/thermal_core.c
> > +++ linux-pm/drivers/thermal/thermal_core.c
> > @@ -806,6 +806,7 @@ int thermal_bind_cdev_to_trip(struct the
> >         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> >         if (!dev)
> >                 return -ENOMEM;
> > +
> >         dev->tz = tz;
> >         dev->cdev = cdev;
> >         dev->trip = trip;
> > @@ -821,8 +822,7 @@ int thermal_bind_cdev_to_trip(struct the
> >
> >         dev->id = result;
> >         sprintf(dev->name, "cdev%d", dev->id);
> > -       result =
> > -           sysfs_create_link(&tz->device.kobj, &cdev->device.kobj,
> > dev->name);
> > +       result = sysfs_create_link(&tz->device.kobj, &cdev-
> > >device.kobj, dev->name);
> >         if (result)
> >                 goto release_ida;
> >
> > @@ -849,24 +849,26 @@ int thermal_bind_cdev_to_trip(struct the
> >
> >         mutex_lock(&tz->lock);
> >         mutex_lock(&cdev->lock);
> > -       list_for_each_entry(pos, &tz->thermal_instances, tz_node)
> > +
> > +       list_for_each_entry(pos, &tz->thermal_instances, tz_node) {
> >                 if (pos->trip == trip && pos->cdev == cdev) {
> >                         result = -EEXIST;
> > -                       break;
> > +                       goto remove_weight_file;
>
> Need to unlock tz->lock and cdev->lock before quitting?

Yes, of course.

Nice catch, thank you!

I'll drop this patch as it's not worth salvaging IMO.

> >                 }
> > -       if (!result) {
> > -               list_add_tail(&dev->tz_node, &tz->thermal_instances);
> > -               list_add_tail(&dev->cdev_node, &cdev-
> > >thermal_instances);
> > -               atomic_set(&tz->need_update, 1);
> > -
> > -               thermal_governor_update_tz(tz, THERMAL_TZ_BIND_CDEV);
> >         }
> > +
> > +       list_add_tail(&dev->tz_node, &tz->thermal_instances);
> > +       list_add_tail(&dev->cdev_node, &cdev->thermal_instances);
> > +       atomic_set(&tz->need_update, 1);
> > +
> > +       thermal_governor_update_tz(tz, THERMAL_TZ_BIND_CDEV);
> > +
> >         mutex_unlock(&cdev->lock);
> >         mutex_unlock(&tz->lock);
> >
> > -       if (!result)
> > -               return 0;
> > +       return 0;
> >
> > +remove_weight_file:
> >         device_remove_file(&tz->device, &dev->weight_attr);
> >  remove_trip_file:
> >         device_remove_file(&tz->device, &dev->attr);
> > @@ -914,6 +916,7 @@ int thermal_unbind_cdev_from_trip(struct
> >
> >         mutex_lock(&tz->lock);
> >         mutex_lock(&cdev->lock);
> > +
> >         list_for_each_entry_safe(pos, next, &tz->thermal_instances,
> > tz_node) {
> >                 if (pos->trip == trip && pos->cdev == cdev) {
> >                         list_del(&pos->tz_node);
> > @@ -923,15 +926,16 @@ int thermal_unbind_cdev_from_trip(struct
> >
> >                         mutex_unlock(&cdev->lock);
> >                         mutex_unlock(&tz->lock);
> > -                       goto unbind;
> > +                       goto free;
> >                 }
> >         }
> > +
> >         mutex_unlock(&cdev->lock);
> >         mutex_unlock(&tz->lock);
> >
> >         return -ENODEV;
> >
> > -unbind:
> > +free:
> >         device_remove_file(&tz->device, &pos->weight_attr);
> >         device_remove_file(&tz->device, &pos->attr);
> >         sysfs_remove_link(&tz->device.kobj, pos->name);
> >
> >
> >
>