firmware: arm_sdei: Introduce sdei_do_local_call()

During the CPU hotplug, the private events are registered, enabled
or unregistered on the specific CPU. It repeats the same steps:
initializing cross call argument, make function call on local CPU,
check the returned error.

This introduces sdei_do_local_call() to cover the first steps. The
other benefit is to make CROSSCALL_INIT and struct sdei_crosscall_args
are only visible to sdei_do_{cross, local}_call().
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-12-gshan@redhat.comSigned-off-by: Will Deacon <will@kernel.org>

drivers/firmware/arm_sdei.c

@@ -85,6 +85,17 @@ struct sdei_crosscall_args {
 		atomic_set(&arg.errors, 0);	\
 	} while (0)
 
+static inline int sdei_do_local_call(smp_call_func_t fn,
+				     struct sdei_event *event)
+{
+	struct sdei_crosscall_args arg;
+
+	CROSSCALL_INIT(arg, event);
+	fn(&arg);
+
+	return arg.first_error;
+}
+
 static inline int sdei_do_cross_call(smp_call_func_t fn,
 				     struct sdei_event *event)
 {
@@ -677,7 +688,7 @@ static int sdei_reregister_shared(void)
 static int sdei_cpuhp_down(unsigned int cpu)
 {
 	struct sdei_event *event;
-	struct sdei_crosscall_args arg;
+	int err;
 
 	/* un-register private events */
 	spin_lock(&sdei_list_lock);
@@ -685,12 +696,11 @@ static int sdei_cpuhp_down(unsigned int cpu)
 		if (event->type == SDEI_EVENT_TYPE_SHARED)
 			continue;
 
-		CROSSCALL_INIT(arg, event);
-		/* call the cross-call function locally... */
-		_local_event_unregister(&arg);
-		if (arg.first_error)
+		err = sdei_do_local_call(_local_event_unregister, event);
+		if (err) {
 			pr_err("Failed to unregister event %u: %d\n",
-			       event->event_num, arg.first_error);
+			       event->event_num, err);
+		}
 	}
 	spin_unlock(&sdei_list_lock);
 
@@ -700,7 +710,7 @@ static int sdei_cpuhp_down(unsigned int cpu)
 static int sdei_cpuhp_up(unsigned int cpu)
 {
 	struct sdei_event *event;
-	struct sdei_crosscall_args arg;
+	int err;
 
 	/* re-register/enable private events */
 	spin_lock(&sdei_list_lock);
@@ -709,20 +719,19 @@ static int sdei_cpuhp_up(unsigned int cpu)
 			continue;
 
 		if (event->reregister) {
-			CROSSCALL_INIT(arg, event);
-			/* call the cross-call function locally... */
-			_local_event_register(&arg);
-			if (arg.first_error)
+			err = sdei_do_local_call(_local_event_register, event);
+			if (err) {
 				pr_err("Failed to re-register event %u: %d\n",
-				       event->event_num, arg.first_error);
+				       event->event_num, err);
+			}
 		}
 
 		if (event->reenable) {
-			CROSSCALL_INIT(arg, event);
-			_local_event_enable(&arg);
-			if (arg.first_error)
+			err = sdei_do_local_call(_local_event_enable, event);
+			if (err) {
 				pr_err("Failed to re-enable event %u: %d\n",
-				       event->event_num, arg.first_error);
+				       event->event_num, err);
+			}
 		}
 	}
 	spin_unlock(&sdei_list_lock);