From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Wed, 26 Nov 2014 09:26:05 +0000 (+0100)
Subject: drm/i915: Check locking in i915_gem_request_unreference
X-Git-Tag: v4.0-rc1~74^2~43^2~103
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=f245860ece9b18394b679c2c55738babc904f506;p=linux.git

drm/i915: Check locking in i915_gem_request_unreference

With refcounting it looks like you can just drop that refcount, but
that's not really the case. So make sure no one forgets.

Motivated by the unlocked call in the mmio flip code.

Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 23a1afd2f7ca..9a9372a42c97 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2046,6 +2046,7 @@ i915_gem_request_reference(struct drm_i915_gem_request *req)
 static inline void
 i915_gem_request_unreference(struct drm_i915_gem_request *req)
 {
+	WARN_ON(!mutex_is_locked(&req->ring->dev->struct_mutex));
 	kref_put(&req->ref, i915_gem_request_free);
 }