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 at amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter at 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);
-               }
+       /* 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;

-- 
2.6.4

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