drm/i915: Remove engine->execlist_lock

The execlist_lock is now completely subsumed by the engine->timeline->lock,
and so we can remove the redundant layer of locking.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161114204105.29171-5-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_debugfs.c

@@ -3256,11 +3256,11 @@ static int i915_engine_info(struct seq_file *m, void *unused)
 				seq_printf(m, "\t\tELSP[1] idle\n");
 			rcu_read_unlock();
 
-			spin_lock_irq(&engine->execlist_lock);
+			spin_lock_irq(&engine->timeline->lock);
 			list_for_each_entry(rq, &engine->execlist_queue, execlist_link) {
 				print_request(m, rq, "\t\tQ ");
 			}
-			spin_unlock_irq(&engine->execlist_lock);
+			spin_unlock_irq(&engine->timeline->lock);
 		} else if (INTEL_GEN(dev_priv) > 6) {
 			seq_printf(m, "\tPP_DIR_BASE: 0x%08x\n",
 				   I915_READ(RING_PP_DIR_BASE(engine)));

drivers/gpu/drm/i915/i915_gem.c

@@ -2717,12 +2717,16 @@ static void i915_gem_cleanup_engine(struct intel_engine_cs *engine)
 	 */
 
 	if (i915.enable_execlists) {
-		spin_lock(&engine->execlist_lock);
+		unsigned long flags;
+
+		spin_lock_irqsave(&engine->timeline->lock, flags);
+
 		INIT_LIST_HEAD(&engine->execlist_queue);
 		i915_gem_request_put(engine->execlist_port[0].request);
 		i915_gem_request_put(engine->execlist_port[1].request);
 		memset(engine->execlist_port, 0, sizeof(engine->execlist_port));
-		spin_unlock(&engine->execlist_lock);
+
+		spin_unlock_irqrestore(&engine->timeline->lock, flags);
 	}
 }
 

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -237,7 +237,6 @@ static void intel_engine_init_timeline(struct intel_engine_cs *engine)
 void intel_engine_setup_common(struct intel_engine_cs *engine)
 {
 	INIT_LIST_HEAD(&engine->execlist_queue);
-	spin_lock_init(&engine->execlist_lock);
 
 	intel_engine_init_timeline(engine);
 	intel_engine_init_hangcheck(engine);

drivers/gpu/drm/i915/intel_lrc.c

@@ -471,7 +471,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 	 */
 
 	spin_lock_irqsave(&engine->timeline->lock, flags);
-	spin_lock(&engine->execlist_lock);
 	list_for_each_entry(cursor, &engine->execlist_queue, execlist_link) {
 		/* Can we combine this request with the current port? It has to
 		 * be the same context/ringbuffer and not have any exceptions
@@ -524,7 +523,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 
 		i915_gem_request_assign(&port->request, last);
 	}
-	spin_unlock(&engine->execlist_lock);
 	spin_unlock_irqrestore(&engine->timeline->lock, flags);
 
 	if (submit)
@@ -633,13 +631,14 @@ static void execlists_submit_request(struct drm_i915_gem_request *request)
 	struct intel_engine_cs *engine = request->engine;
 	unsigned long flags;
 
-	spin_lock_irqsave(&engine->execlist_lock, flags);
+	/* Will be called from irq-context when using foreign fences. */
+	spin_lock_irqsave(&engine->timeline->lock, flags);
 
 	list_add_tail(&request->execlist_link, &engine->execlist_queue);
 	if (execlists_elsp_idle(engine))
 		tasklet_hi_schedule(&engine->irq_tasklet);
 
-	spin_unlock_irqrestore(&engine->execlist_lock, flags);
+	spin_unlock_irqrestore(&engine->timeline->lock, flags);
 }
 
 int intel_logical_ring_alloc_request_extras(struct drm_i915_gem_request *request)

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -335,7 +335,6 @@ struct intel_engine_cs {
 
 	/* Execlists */
 	struct tasklet_struct irq_tasklet;
-	spinlock_t execlist_lock; /* used inside tasklet, use spin_lock_bh */
 	struct execlist_port {
 		struct drm_i915_gem_request *request;
 		unsigned int count;