[PATCH 06/49] drm/i915: Give each sw_fence its own lockclass

[Chris Wilson]

Localise the static struct lock_class_key to the caller of
i915_sw_fence_init() so that we create a lock_class instance for each
unique sw_fence rather than all sw_fences sharing the same
lock_class. This eliminate some lockdep false positive when using fences
from within fence callbacks.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_sw_fence.c |  7 +++++--
 drivers/gpu/drm/i915/i915_sw_fence.h | 11 ++++++++++-
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c
index 95f2f12e0917..147420ccf49c 100644
--- a/drivers/gpu/drm/i915/i915_sw_fence.c
+++ b/drivers/gpu/drm/i915/i915_sw_fence.c
@@ -116,11 +116,14 @@ static void i915_sw_fence_await(struct i915_sw_fence *fence)
 	WARN_ON(atomic_inc_return(&fence->pending) <= 1);
 }
 
-void i915_sw_fence_init(struct i915_sw_fence *fence, i915_sw_fence_notify_t fn)
+void __i915_sw_fence_init(struct i915_sw_fence *fence,
+			  i915_sw_fence_notify_t fn,
+			  const char *name,
+			  struct lock_class_key *key)
 {
 	BUG_ON((unsigned long)fn & ~I915_SW_FENCE_MASK);
 
-	init_waitqueue_head(&fence->wait);
+	__init_waitqueue_head(&fence->wait, name, key);
 	kref_init(&fence->kref);
 	atomic_set(&fence->pending, 1);
 	fence->flags = (unsigned long)fn;
diff --git a/drivers/gpu/drm/i915/i915_sw_fence.h b/drivers/gpu/drm/i915/i915_sw_fence.h
index 707dfc4f0da5..a5546eb2b5cd 100644
--- a/drivers/gpu/drm/i915/i915_sw_fence.h
+++ b/drivers/gpu/drm/i915/i915_sw_fence.h
@@ -40,7 +40,16 @@ typedef int (*i915_sw_fence_notify_t)(struct i915_sw_fence *,
 				      enum i915_sw_fence_notify state);
 #define __i915_sw_fence_call __aligned(4)
 
-void i915_sw_fence_init(struct i915_sw_fence *fence, i915_sw_fence_notify_t fn);
+void __i915_sw_fence_init(struct i915_sw_fence *fence,
+			  i915_sw_fence_notify_t fn,
+			  const char *name,
+			  struct lock_class_key *key);
+#define i915_sw_fence_init(fence, fn) do {			\
+	static struct lock_class_key __key; 			\
+								\
+	__i915_sw_fence_init((fence), fn, #fence, &__key);	\
+} while (0)
+
 void i915_sw_fence_commit(struct i915_sw_fence *fence);
 
 int i915_sw_fence_await_sw_fence(struct i915_sw_fence *fence,
-- 
2.10.2