| Message ID | 1452346126-20091-1-git-send-email-daniel.vetter@ffwll.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Daniel, Thank you for the patch. On Saturday 09 January 2016 14:28:46 Daniel Vetter wrote: > There's really no reason to not do so, instead of replicating this > for every use-case and every driver. Now we can't just nuke the events, > since that would still mean that all drm_event users would need to know > when that has happened, since calling e.g. drm_send_event isn't allowed > any more. Instead just unlink them from the file, and detect this case > and handle it appropriately in all functions. > > v2: Adjust existing kerneldoc too. > > Cc: Alex Deucher <alexander.deucher@amd.com> > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> > --- > drivers/gpu/drm/drm_fops.c | 35 ++++++++++++++++++++++++++--------- > include/drm/drmP.h | 2 ++ > 2 files changed, 28 insertions(+), 9 deletions(-) > > diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c > index d85af1b2a238..d32b24c74e08 100644 > --- a/drivers/gpu/drm/drm_fops.c > +++ b/drivers/gpu/drm/drm_fops.c > @@ -264,6 +264,7 @@ static int drm_open_helper(struct file *filp, struct > drm_minor *minor) INIT_LIST_HEAD(&priv->fbs); > mutex_init(&priv->fbs_lock); > INIT_LIST_HEAD(&priv->blobs); > + INIT_LIST_HEAD(&priv->pending_event_list); > INIT_LIST_HEAD(&priv->event_list); > init_waitqueue_head(&priv->event_wait); > priv->event_space = 4096; /* set aside 4k for event buffer */ > @@ -353,18 +354,16 @@ static void drm_events_release(struct drm_file > *file_priv) { > struct drm_device *dev = file_priv->minor->dev; > struct drm_pending_event *e, *et; > - struct drm_pending_vblank_event *v, *vt; > unsigned long flags; > > spin_lock_irqsave(&dev->event_lock, flags); > > - /* Remove pending flips */ > - list_for_each_entry_safe(v, vt, &dev->vblank_event_list, base.link) > - if (v->base.file_priv == file_priv) { > - list_del(&v->base.link); > - drm_vblank_put(dev, v->pipe); > - v->base.destroy(&v->base); > - } Where does this code go ? > + /* Unlink pending events */ > + list_for_each_entry_safe(e, et, &file_priv->pending_event_list, > + pending_link) { > + list_del(&e->pending_link); > + e->file_priv = NULL; > + } > > /* Remove unconsumed events */ > list_for_each_entry_safe(e, et, &file_priv->event_list, link) { > @@ -712,6 +711,7 @@ int drm_event_reserve_init(struct drm_device *dev, > file_priv->event_space -= e->length; > > p->event = e; > + list_add(&p->pending_link, &file_priv->pending_event_list); > p->file_priv = file_priv; > > /* we *could* pass this in as arg, but everyone uses kfree: */ > @@ -736,7 +736,10 @@ void drm_event_cancel_free(struct drm_device *dev, > { > unsigned long flags; > spin_lock_irqsave(&dev->event_lock, flags); > - p->file_priv->event_space += p->event->length; > + if (p->file_priv) { > + p->file_priv->event_space += p->event->length; > + list_del(&p->pending_link); > + } > spin_unlock_irqrestore(&dev->event_lock, flags); > p->destroy(p); > } > @@ -750,11 +753,21 @@ EXPORT_SYMBOL(drm_event_cancel_free); > * This function sends the event @e, initialized with > drm_event_reserve_init(), > * to its associated userspace DRM file. Callers must already hold > * dev->event_lock, see drm_send_event() for the unlocked version. > + * > + * Note that the core will take care of unlinking and disarming events when > the > + * corresponding DRM file is closed. Drivers need to worry about that and s/need to/need not/ ? > can > + * call this function upon completion of the asynchrnous work s/asynchrnous/asynchronous/ > unconditionally. */ > void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event > *e) { > assert_spin_locked(&dev->event_lock); > > + if (!e->file_priv) { I don't think this could happen before this patch as e->file_priv is dereferenced below, and I don't see anything in this patch that makes the condition possible. > + e->destroy(e); > + return; > + } > + > + list_del(&e->pending_link); > list_add_tail(&e->link, > &e->file_priv->event_list); > wake_up_interruptible(&e->file_priv->event_wait); > @@ -769,6 +782,10 @@ EXPORT_SYMBOL(drm_send_event_locked); > * This function sends the event @e, initialized with > drm_event_reserve_init(), > * to its associated userspace DRM file. This function acquires > dev->event_lock, > * see drm_send_event_locked() for callers which already hold this lock. > + * > + * Note that the core will take care of unlinking and disarming events when > the > + * corresponding DRM file is closed. Drivers need to worry about that and s/need to/need not/ ? > can > + * call this function upon completion of the asynchrnous work s/asynchrnous/asynchronous/ > unconditionally. */ > void drm_send_event(struct drm_device *dev, struct drm_pending_event *e) > { > diff --git a/include/drm/drmP.h b/include/drm/drmP.h > index ae73abf5c2cf..3d78a7406d54 100644 > --- a/include/drm/drmP.h > +++ b/include/drm/drmP.h > @@ -283,6 +283,7 @@ struct drm_ioctl_desc { > struct drm_pending_event { > struct drm_event *event; > struct list_head link; > + struct list_head pending_link; > struct drm_file *file_priv; > pid_t pid; /* pid of requester, no guarantee it's valid by the time > we deliver the event, for tracing only */ > @@ -346,6 +347,7 @@ struct drm_file { > struct list_head blobs; > > wait_queue_head_t event_wait; > + struct list_head pending_event_list; > struct list_head event_list; > int event_space;
Hi, On 10 January 2016 at 23:48, Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote: > On Saturday 09 January 2016 14:28:46 Daniel Vetter wrote: >> @@ -353,18 +354,16 @@ static void drm_events_release(struct drm_file >> *file_priv) { >> struct drm_device *dev = file_priv->minor->dev; >> struct drm_pending_event *e, *et; >> - struct drm_pending_vblank_event *v, *vt; >> unsigned long flags; >> >> spin_lock_irqsave(&dev->event_lock, flags); >> >> - /* Remove pending flips */ >> - list_for_each_entry_safe(v, vt, &dev->vblank_event_list, base.link) >> - if (v->base.file_priv == file_priv) { >> - list_del(&v->base.link); >> - drm_vblank_put(dev, v->pipe); >> - v->base.destroy(&v->base); >> - } > > Where does this code go ? It doesn't: instead of deleting the events, the helpers to either cancel or send the event just notice that file_priv is NULL and bail out early. >> + /* Unlink pending events */ >> + list_for_each_entry_safe(e, et, &file_priv->pending_event_list, >> + pending_link) { >> + list_del(&e->pending_link); >> + e->file_priv = NULL; >> + } file_priv gets reset here ... >> @@ -736,7 +736,10 @@ void drm_event_cancel_free(struct drm_device *dev, >> { >> unsigned long flags; >> spin_lock_irqsave(&dev->event_lock, flags); >> - p->file_priv->event_space += p->event->length; >> + if (p->file_priv) { >> + p->file_priv->event_space += p->event->length; >> + list_del(&p->pending_link); >> + } >> spin_unlock_irqrestore(&dev->event_lock, flags); >> p->destroy(p); Allowing us to DTRT here ... >> void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event >> *e) { >> assert_spin_locked(&dev->event_lock); >> >> + if (!e->file_priv) { > > I don't think this could happen before this patch as e->file_priv is > dereferenced below, and I don't see anything in this patch that makes the > condition possible. > >> + e->destroy(e); >> + return; >> + } ... and now here. This looks good to me, and a good sight better than doing it in every driver. Still drowning in stuff after three weeks off though, so the best I can offer for the series right now is: Acked-by: Daniel Stone <daniels@collabora.com> Cheers, Daniel
Hi Daniel, On Monday 11 January 2016 14:51:46 Daniel Stone wrote: > On 10 January 2016 at 23:48, Laurent Pinchart wrote: > > On Saturday 09 January 2016 14:28:46 Daniel Vetter wrote: > >> @@ -353,18 +354,16 @@ static void drm_events_release(struct drm_file > >> *file_priv) { > >> > >> struct drm_device *dev = file_priv->minor->dev; > >> struct drm_pending_event *e, *et; > >> > >> - struct drm_pending_vblank_event *v, *vt; > >> > >> unsigned long flags; > >> > >> spin_lock_irqsave(&dev->event_lock, flags); > >> > >> - /* Remove pending flips */ > >> - list_for_each_entry_safe(v, vt, &dev->vblank_event_list, base.link) > >> - if (v->base.file_priv == file_priv) { > >> - list_del(&v->base.link); > >> - drm_vblank_put(dev, v->pipe); > >> - v->base.destroy(&v->base); > >> - } > > > > Where does this code go ? > > It doesn't: instead of deleting the events, the helpers to either > cancel or send the event just notice that file_priv is NULL and bail > out early. Thank you for the explanation. What bothered me was that the drm_vblank_put() call got dropped. With v2 of this patch series that splits that change to a separate patch it's easier to understand. > >> + /* Unlink pending events */ > >> + list_for_each_entry_safe(e, et, &file_priv->pending_event_list, > >> + pending_link) { > >> + list_del(&e->pending_link); > >> + e->file_priv = NULL; > >> + } > > file_priv gets reset here ... > > >> @@ -736,7 +736,10 @@ void drm_event_cancel_free(struct drm_device *dev, > >> > >> { > >> > >> unsigned long flags; > >> spin_lock_irqsave(&dev->event_lock, flags); > >> > >> - p->file_priv->event_space += p->event->length; > >> + if (p->file_priv) { > >> + p->file_priv->event_space += p->event->length; > >> + list_del(&p->pending_link); > >> + } > >> > >> spin_unlock_irqrestore(&dev->event_lock, flags); > >> p->destroy(p); > > Allowing us to DTRT here ... > > >> void drm_send_event_locked(struct drm_device *dev, struct > >> drm_pending_event > >> > >> *e) { > >> > >> assert_spin_locked(&dev->event_lock); > >> > >> + if (!e->file_priv) { > > > > I don't think this could happen before this patch as e->file_priv is > > dereferenced below, and I don't see anything in this patch that makes the > > condition possible. > > > >> + e->destroy(e); > >> + return; > >> + } > > ... and now here. > > This looks good to me, and a good sight better than doing it in every > driver. Still drowning in stuff after three weeks off though, so the > best I can offer for the series right now is: > Acked-by: Daniel Stone <daniels@collabora.com>
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c index d85af1b2a238..d32b24c74e08 100644 --- a/drivers/gpu/drm/drm_fops.c +++ b/drivers/gpu/drm/drm_fops.c @@ -264,6 +264,7 @@ static int drm_open_helper(struct file *filp, struct drm_minor *minor) INIT_LIST_HEAD(&priv->fbs); mutex_init(&priv->fbs_lock); INIT_LIST_HEAD(&priv->blobs); + INIT_LIST_HEAD(&priv->pending_event_list); INIT_LIST_HEAD(&priv->event_list); init_waitqueue_head(&priv->event_wait); priv->event_space = 4096; /* set aside 4k for event buffer */ @@ -353,18 +354,16 @@ static void drm_events_release(struct drm_file *file_priv) { struct drm_device *dev = file_priv->minor->dev; struct drm_pending_event *e, *et; - struct drm_pending_vblank_event *v, *vt; unsigned long flags; spin_lock_irqsave(&dev->event_lock, flags); - /* Remove pending flips */ - list_for_each_entry_safe(v, vt, &dev->vblank_event_list, base.link) - if (v->base.file_priv == file_priv) { - list_del(&v->base.link); - drm_vblank_put(dev, v->pipe); - v->base.destroy(&v->base); - } + /* Unlink pending events */ + list_for_each_entry_safe(e, et, &file_priv->pending_event_list, + pending_link) { + list_del(&e->pending_link); + e->file_priv = NULL; + } /* Remove unconsumed events */ list_for_each_entry_safe(e, et, &file_priv->event_list, link) { @@ -712,6 +711,7 @@ int drm_event_reserve_init(struct drm_device *dev, file_priv->event_space -= e->length; p->event = e; + list_add(&p->pending_link, &file_priv->pending_event_list); p->file_priv = file_priv; /* we *could* pass this in as arg, but everyone uses kfree: */ @@ -736,7 +736,10 @@ void drm_event_cancel_free(struct drm_device *dev, { unsigned long flags; spin_lock_irqsave(&dev->event_lock, flags); - p->file_priv->event_space += p->event->length; + if (p->file_priv) { + p->file_priv->event_space += p->event->length; + list_del(&p->pending_link); + } spin_unlock_irqrestore(&dev->event_lock, flags); p->destroy(p); } @@ -750,11 +753,21 @@ EXPORT_SYMBOL(drm_event_cancel_free); * This function sends the event @e, initialized with drm_event_reserve_init(), * to its associated userspace DRM file. Callers must already hold * dev->event_lock, see drm_send_event() for the unlocked version. + * + * Note that the core will take care of unlinking and disarming events when the + * corresponding DRM file is closed. Drivers need to worry about that and can + * call this function upon completion of the asynchrnous work unconditionally. */ void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e) { assert_spin_locked(&dev->event_lock); + if (!e->file_priv) { + e->destroy(e); + return; + } + + list_del(&e->pending_link); list_add_tail(&e->link, &e->file_priv->event_list); wake_up_interruptible(&e->file_priv->event_wait); @@ -769,6 +782,10 @@ EXPORT_SYMBOL(drm_send_event_locked); * This function sends the event @e, initialized with drm_event_reserve_init(), * to its associated userspace DRM file. This function acquires dev->event_lock, * see drm_send_event_locked() for callers which already hold this lock. + * + * Note that the core will take care of unlinking and disarming events when the + * corresponding DRM file is closed. Drivers need to worry about that and can + * call this function upon completion of the asynchrnous work unconditionally. */ void drm_send_event(struct drm_device *dev, struct drm_pending_event *e) { diff --git a/include/drm/drmP.h b/include/drm/drmP.h index ae73abf5c2cf..3d78a7406d54 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -283,6 +283,7 @@ struct drm_ioctl_desc { struct drm_pending_event { struct drm_event *event; struct list_head link; + struct list_head pending_link; struct drm_file *file_priv; pid_t pid; /* pid of requester, no guarantee it's valid by the time we deliver the event, for tracing only */ @@ -346,6 +347,7 @@ struct drm_file { struct list_head blobs; wait_queue_head_t event_wait; + struct list_head pending_event_list; struct list_head event_list; int event_space;
There's really no reason to not do so, instead of replicating this for every use-case and every driver. Now we can't just nuke the events, since that would still mean that all drm_event users would need to know when that has happened, since calling e.g. drm_send_event isn't allowed any more. Instead just unlink them from the file, and detect this case and handle it appropriately in all functions. v2: Adjust existing kerneldoc too. Cc: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> --- drivers/gpu/drm/drm_fops.c | 35 ++++++++++++++++++++++++++--------- include/drm/drmP.h | 2 ++ 2 files changed, 28 insertions(+), 9 deletions(-)