drm/i915: Spinlocks in tasklets can use spin_(un)lock_irq

The tasklets callbacks are only called from tasklet context so
it is safe do to this.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170321105511.18269-1-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/i915_guc_submission.c

@@ -573,7 +573,6 @@ static bool i915_guc_dequeue(struct intel_engine_cs *engine)
 {
 	struct execlist_port *port = engine->execlist_port;
 	struct drm_i915_gem_request *last = port[0].request;
-	unsigned long flags;
 	struct rb_node *rb;
 	bool submit = false;
 
@@ -589,7 +588,7 @@ static bool i915_guc_dequeue(struct intel_engine_cs *engine)
 	if (!READ_ONCE(engine->execlist_first))
 		return false;
 
-	spin_lock_irqsave(&engine->timeline->lock, flags);
+	spin_lock_irq(&engine->timeline->lock);
 	rb = engine->execlist_first;
 	while (rb) {
 		struct drm_i915_gem_request *rq =
@@ -619,7 +618,7 @@ static bool i915_guc_dequeue(struct intel_engine_cs *engine)
 		nested_enable_signaling(last);
 		engine->execlist_first = rb;
 	}
-	spin_unlock_irqrestore(&engine->timeline->lock, flags);
+	spin_unlock_irq(&engine->timeline->lock);
 
 	return submit;
 }

drivers/gpu/drm/i915/intel_lrc.c

@@ -399,7 +399,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 {
 	struct drm_i915_gem_request *last;
 	struct execlist_port *port = engine->execlist_port;
-	unsigned long flags;
 	struct rb_node *rb;
 	bool submit = false;
 
@@ -448,7 +447,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 	 * and context switches) submission.
 	 */
 
-	spin_lock_irqsave(&engine->timeline->lock, flags);
+	spin_lock_irq(&engine->timeline->lock);
 	rb = engine->execlist_first;
 	while (rb) {
 		struct drm_i915_gem_request *cursor =
@@ -500,7 +499,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 		i915_gem_request_assign(&port->request, last);
 		engine->execlist_first = rb;
 	}
-	spin_unlock_irqrestore(&engine->timeline->lock, flags);
+	spin_unlock_irq(&engine->timeline->lock);
 
 	if (submit)
 		execlists_submit_ports(engine);