[Intel-gfx] [PATCH 06/29] drm/i915: unload: fix unpin_work related races

[Chris Wilson]

From: Daniel Vetter <daniel.vetter at ffwll.ch>

Kill any outstanding unpin_work when destroying the corresponding
crtc. Then flush the workqueue before the gem teardown, in case
any unpin work is still outstanding.

Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_dma.c      |    3 +++
 drivers/gpu/drm/i915/intel_display.c |   30 ++++++++++++++++++++++--------
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 8e3ae34..bb59058 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -2282,6 +2282,9 @@ int i915_driver_unload(struct drm_device *dev)
 	intel_opregion_free(dev, 0);
 
 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+		/* Flush any outstanding unpin_work. */
+		flush_workqueue(dev_priv->wq);
+
 		i915_gem_free_all_phys_object(dev);
 
 		mutex_lock(&dev->struct_mutex);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index ef26839..6ccb797 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4902,14 +4902,6 @@ void intel_mark_busy(struct drm_device *dev, struct drm_gem_object *obj)
 	}
 }
 
-static void intel_crtc_destroy(struct drm_crtc *crtc)
-{
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-
-	drm_crtc_cleanup(crtc);
-	kfree(intel_crtc);
-}
-
 struct intel_unpin_work {
 	struct work_struct work;
 	struct drm_device *dev;
@@ -4919,6 +4911,28 @@ struct intel_unpin_work {
 	int pending;
 };
 
+static void intel_crtc_destroy(struct drm_crtc *crtc)
+{
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
+	struct intel_unpin_work *work;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->event_lock, flags);
+	work = intel_crtc->unpin_work;
+	intel_crtc->unpin_work = NULL;
+	spin_unlock_irqrestore(&dev->event_lock, flags);
+
+	if (work) {
+		cancel_work_sync(&work->work);
+		kfree(work);
+	}
+
+	drm_crtc_cleanup(crtc);
+
+	kfree(intel_crtc);
+}
+
 static void intel_unpin_work_fn(struct work_struct *__work)
 {
 	struct intel_unpin_work *work =
-- 
1.7.1