Patch "drm/i915: Fix oopses in the overlay code due to i915_gem_active stuff" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

drm/i915: Fix oopses in the overlay code due to i915_gem_active stuff

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     drm-i915-fix-oopses-in-the-overlay-code-due-to-i915_gem_active-stuff.patch

and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <[email protected]>
Date: Wed, 7 Dec 2016 17:56:47 +0000
Subject: drm/i915: Fix oopses in the overlay code due to i915_gem_active stuff
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From: Ville Syrjälä <[email protected]>

commit b72eb5ffa6d8601d9ba72619d75fb5b27723743a upstream.

The i915_gem_active stuff doesn't like a NULL ->retire hook, but the overlay code can set it to NULL. That obviously ends up oopsing. Fix it by introducing a new helper to assign the retirement callback that will switch out the NULL function pointer with i915_gem_retire_noop.

---
 drivers/gpu/drm/i915/i915_gem_request.h |   19 +++++++++++++++++++
 drivers/gpu/drm/i915/intel_overlay.c    |    3 ++-
 2 files changed, 21 insertions(+), 1 deletion(-)

@@ -344,6 +344,25 @@ i915_gem_active_set(struct i915_gem_acti
 	rcu_assign_pointer(active->request, request);
 }
 
+/**
+ * i915_gem_active_set_retire_fn - updates the retirement callback
+ * @active - the active tracker
+ * @fn - the routine called when the request is retired
+ * @mutex - struct_mutex used to guard retirements
+ *
+ * i915_gem_active_set_retire_fn() updates the function pointer that
+ * is called when the final request associated with the @active tracker
+ * is retired.
+ */
+static inline void
+i915_gem_active_set_retire_fn(struct i915_gem_active *active,
+			      i915_gem_retire_fn fn,
+			      struct mutex *mutex)
+{
+	lockdep_assert_held(mutex);
+	active->retire = fn ?: i915_gem_retire_noop;
+}
+
 static inline struct drm_i915_gem_request *
 __i915_gem_active_peek(const struct i915_gem_active *active)
 {

@@ -216,7 +216,8 @@ static void intel_overlay_submit_request
 {
 	GEM_BUG_ON(i915_gem_active_peek(&overlay->last_flip,
 					&overlay->i915->drm.struct_mutex));
-	overlay->last_flip.retire = retire;
+	i915_gem_active_set_retire_fn(&overlay->last_flip, retire,
+				      &overlay->i915->drm.struct_mutex);
 	i915_gem_active_set(&overlay->last_flip, req);
 	i915_add_request(req);
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/drm-i915-fix-oopses-in-the-overlay-code-due-to-i915_gem_active-stuff.patch queue-4.9/drm-i915-initialize-overlay-last_flip-properly.patch queue-4.9/drm-i915-force-vdd-off-on-the-new-power-seqeuencer-before-starting-to-use-it.patch queue-4.9/drm-i915-fix-oops-in-overlay-due-to-frontbuffer-tracking.patch