From f52c6d0df6909a0412c347c8e442acc22ce94747 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 27 Aug 2019 14:26:31 +0100
Subject: drm/i915: Only activate i915_active debugobject once
Git-commit: f52c6d0df6909a0412c347c8e442acc22ce94747
Patch-mainline: v5.5-rc1
References: bsc#1152489

The point of debug_object_activate is to mark the first, and only the
first, acquisition. The object then remains active until the last
release.  However, we marked up all successful first acquires even though
we allowed concurrent parties to try and acquire the i915_active
simultaneously (serialised by the i915_active.mutex).

Testcase: igt/gem_mmap_gtt/fault-concurrent
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190827132631.18627-1-chris@chris-wilson.co.uk
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/i915/i915_active.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
index 48e16ad93bbd..6a447f1d0110 100644
--- a/drivers/gpu/drm/i915/i915_active.c
+++ b/drivers/gpu/drm/i915/i915_active.c
@@ -92,12 +92,16 @@ static void debug_active_init(struct i915_active *ref)
 
 static void debug_active_activate(struct i915_active *ref)
 {
-	debug_object_activate(ref, &active_debug_desc);
+	lockdep_assert_held(&ref->mutex);
+	if (!atomic_read(&ref->count)) /* before the first inc */
+		debug_object_activate(ref, &active_debug_desc);
 }
 
 static void debug_active_deactivate(struct i915_active *ref)
 {
-	debug_object_deactivate(ref, &active_debug_desc);
+	lockdep_assert_held(&ref->mutex);
+	if (!atomic_read(&ref->count)) /* after the last dec */
+		debug_object_deactivate(ref, &active_debug_desc);
 }
 
 static void debug_active_fini(struct i915_active *ref)
-- 
2.28.0