linux-kernel - Re: [PATCH] drm/fb-helper: Add missed unlocks in setcmap

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Message-ID: <CAKMK7uE3Mr2aOEvdnVrQWE=xc-8OQ1vkv9MdURaMVPHXKF5jwQ@mail.gmail.com>
Date:   Thu, 3 Dec 2020 17:39:25 +0100
From:   Daniel Vetter <daniel@...ll.ch>
To:     Peter Rosin <peda@...ntia.se>
Cc:     Chuhong Yuan <hslester96@...il.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/fb-helper: Add missed unlocks in setcmap_legacy()

On Thu, Dec 3, 2020 at 5:11 PM Peter Rosin <peda@...ntia.se> wrote:
>
> Hi!
>
> On 2020-12-03 15:42, Chuhong Yuan wrote:
> > setcmap_legacy() does not call drm_modeset_unlock_all() in some exits,
> > add the missed unlocks with goto to fix it.
> >
> > Fixes: 964c60063bff ("drm/fb-helper: separate the fb_setcmap helper into atomic and legacy paths")
> > Signed-off-by: Chuhong Yuan <hslester96@...il.com>
>
> Yup, my patch fumbled the locking. Sorry, and thanks for cleaning up my mess!
>
> Acked-by: Peter Rosin <peda@...ntia.se>
>
> (Spelled that as Ached-by at first, what does that mean??)

Merged already before I've seen your ack here (and we don't rebase so
can't add it now), thanks for the patch and all.
-Daniel

>
> Cheers,
> Peter
>
> > ---
> >  drivers/gpu/drm/drm_fb_helper.c | 15 ++++++++++-----
> >  1 file changed, 10 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> > index 1543d9d10970..8033467db4be 100644
> > --- a/drivers/gpu/drm/drm_fb_helper.c
> > +++ b/drivers/gpu/drm/drm_fb_helper.c
> > @@ -923,11 +923,15 @@ static int setcmap_legacy(struct fb_cmap *cmap, struct fb_info *info)
> >       drm_modeset_lock_all(fb_helper->dev);
> >       drm_client_for_each_modeset(modeset, &fb_helper->client) {
> >               crtc = modeset->crtc;
> > -             if (!crtc->funcs->gamma_set || !crtc->gamma_size)
> > -                     return -EINVAL;
> > +             if (!crtc->funcs->gamma_set || !crtc->gamma_size) {
> > +                     ret = -EINVAL;
> > +                     goto out;
> > +             }
> >
> > -             if (cmap->start + cmap->len > crtc->gamma_size)
> > -                     return -EINVAL;
> > +             if (cmap->start + cmap->len > crtc->gamma_size) {
> > +                     ret = -EINVAL;
> > +                     goto out;
> > +             }
> >
> >               r = crtc->gamma_store;
> >               g = r + crtc->gamma_size;
> > @@ -940,8 +944,9 @@ static int setcmap_legacy(struct fb_cmap *cmap, struct fb_info *info)
> >               ret = crtc->funcs->gamma_set(crtc, r, g, b,
> >                                            crtc->gamma_size, NULL);
> >               if (ret)
> > -                     return ret;
> > +                     goto out;
> >       }
> > +out:
> >       drm_modeset_unlock_all(fb_helper->dev);
> >
> >       return ret;
> >



-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch