drm: Clean up pending events in the core

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.

v3: Improve wording of the kerneldoc and split out vblank cleanup (Laurent).

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com> (v1)
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-2-git-send-email-daniel.vetter@ffwll.ch

diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index eb6a02f..afe8c53 100644 (file)
--- 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 */
@@ -366,6 +367,13 @@ static void drm_events_release(struct drm_file *file_priv)
                        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) {
                list_del(&e->link);
@@ -712,6 +720,7 @@ int drm_event_reserve_init_locked(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: */
@@ -774,7 +783,10 @@ 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);
 }
@@ -788,11 +800,22 @@ 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 not worry about whether the
+ * DRM file for this event still exists and can call this function upon
+ * completion of the asynchronous 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);
@@ -807,6 +830,11 @@ 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 not worry about whether the
+ * DRM file for this event still exists and can call this function upon
+ * completion of the asynchronous 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 1b71852..3c8422c 100644 (file)
--- 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;