drm/i915: Extract active lookup engine to a helper

Move active engine lookup to exported i915_request_active_engine.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
[danvet: Slight rebase, engine->sched.lock is still called
engine->active.lock.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210324121335.2307063-2-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/gem/i915_gem_context.c

@@ -386,38 +386,6 @@ static bool __cancel_engine(struct intel_engine_cs *engine)
 	return intel_engine_pulse(engine) == 0;
 }
 
-static bool
-__active_engine(struct i915_request *rq, struct intel_engine_cs **active)
-{
-	struct intel_engine_cs *engine, *locked;
-	bool ret = false;
-
-	/*
-	 * Serialise with __i915_request_submit() so that it sees
-	 * is-banned?, or we know the request is already inflight.
-	 *
-	 * Note that rq->engine is unstable, and so we double
-	 * check that we have acquired the lock on the final engine.
-	 */
-	locked = READ_ONCE(rq->engine);
-	spin_lock_irq(&locked->active.lock);
-	while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
-		spin_unlock(&locked->active.lock);
-		locked = engine;
-		spin_lock(&locked->active.lock);
-	}
-
-	if (i915_request_is_active(rq)) {
-		if (!__i915_request_is_complete(rq))
-			*active = locked;
-		ret = true;
-	}
-
-	spin_unlock_irq(&locked->active.lock);
-
-	return ret;
-}
-
 static struct intel_engine_cs *active_engine(struct intel_context *ce)
 {
 	struct intel_engine_cs *engine = NULL;
@@ -445,7 +413,7 @@ static struct intel_engine_cs *active_engine(struct intel_context *ce)
 		/* Check with the backend if the request is inflight */
 		found = true;
 		if (likely(rcu_access_pointer(rq->timeline) == ce->timeline))
-			found = __active_engine(rq, &engine);
+			found = i915_request_active_engine(rq, &engine);
 
 		i915_request_put(rq);
 		if (found)

drivers/gpu/drm/i915/i915_request.c

@@ -244,6 +244,50 @@ static void __i915_request_fill(struct i915_request *rq, u8 val)
 	memset(vaddr + head, val, rq->postfix - head);
 }
 
+/**
+ * i915_request_active_engine
+ * @rq: request to inspect
+ * @active: pointer in which to return the active engine
+ *
+ * Fills the currently active engine to the @active pointer if the request
+ * is active and still not completed.
+ *
+ * Returns true if request was active or false otherwise.
+ */
+bool
+i915_request_active_engine(struct i915_request *rq,
+			   struct intel_engine_cs **active)
+{
+	struct intel_engine_cs *engine, *locked;
+	bool ret = false;
+
+	/*
+	 * Serialise with __i915_request_submit() so that it sees
+	 * is-banned?, or we know the request is already inflight.
+	 *
+	 * Note that rq->engine is unstable, and so we double
+	 * check that we have acquired the lock on the final engine.
+	 */
+	locked = READ_ONCE(rq->engine);
+	spin_lock_irq(&locked->active.lock);
+	while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
+		spin_unlock(&locked->active.lock);
+		locked = engine;
+		spin_lock(&locked->active.lock);
+	}
+
+	if (i915_request_is_active(rq)) {
+		if (!__i915_request_is_complete(rq))
+			*active = locked;
+		ret = true;
+	}
+
+	spin_unlock_irq(&locked->active.lock);
+
+	return ret;
+}
+
+
 static void remove_from_engine(struct i915_request *rq)
 {
 	struct intel_engine_cs *engine, *locked;

drivers/gpu/drm/i915/i915_request.h

@@ -627,4 +627,8 @@ i915_request_active_seqno(const struct i915_request *rq)
 	return hwsp_phys_base + hwsp_relative_offset;
 }
 
+bool
+i915_request_active_engine(struct i915_request *rq,
+			   struct intel_engine_cs **active);
+
 #endif /* I915_REQUEST_H */