Merge tag 'staging-5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

Pullstaging driver fixes from Greg KH:
 "Here are two staging driver fixes for 5.17-rc4.  These are:

   - fbtft error path fix

   - vc04_services rcu dereference fix

  Both of these have been in linux-next for a while with no reported
  issues"

* tag 'staging-5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: fbtft: Fix error path in fbtft_driver_module_init()
  staging: vc04_services: Fix RCU dereference check

Author: torvalds

drivers/staging/fbtft/fbtft.h

@@ -334,7 +334,10 @@ static int __init fbtft_driver_module_init(void)                           \
 	ret = spi_register_driver(&fbtft_driver_spi_driver);               \
 	if (ret < 0)                                                       \
 		return ret;                                                \
-	return platform_driver_register(&fbtft_driver_platform_driver);    \
+	ret = platform_driver_register(&fbtft_driver_platform_driver);     \
+	if (ret < 0)                                                       \
+		spi_unregister_driver(&fbtft_driver_spi_driver);           \
+	return ret;                                                        \
 }                                                                          \
 									   \
 static void __exit fbtft_driver_module_exit(void)                          \

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c

@@ -1058,15 +1058,27 @@ service_callback(enum vchiq_reason reason, struct vchiq_header *header,
 
 	DEBUG_TRACE(SERVICE_CALLBACK_LINE);
 
+	rcu_read_lock();
 	service = handle_to_service(handle);
-	if (WARN_ON(!service))
+	if (WARN_ON(!service)) {
+		rcu_read_unlock();
 		return VCHIQ_SUCCESS;
+	}
 
 	user_service = (struct user_service *)service->base.userdata;
 	instance = user_service->instance;
 
-	if (!instance || instance->closing)
+	if (!instance || instance->closing) {
+		rcu_read_unlock();
 		return VCHIQ_SUCCESS;
+	}
+
+	/*
+	 * As hopping around different synchronization mechanism,
+	 * taking an extra reference results in simpler implementation.
+	 */
+	vchiq_service_get(service);
+	rcu_read_unlock();
 
 	vchiq_log_trace(vchiq_arm_log_level,
 			"%s - service %lx(%d,%p), reason %d, header %lx, instance %lx, bulk_userdata %lx",
@@ -1097,6 +1109,7 @@ service_callback(enum vchiq_reason reason, struct vchiq_header *header,
 							bulk_userdata);
 				if (status != VCHIQ_SUCCESS) {
 					DEBUG_TRACE(SERVICE_CALLBACK_LINE);
+					vchiq_service_put(service);
 					return status;
 				}
 			}
@@ -1105,10 +1118,12 @@ service_callback(enum vchiq_reason reason, struct vchiq_header *header,
 			if (wait_for_completion_interruptible(&user_service->remove_event)) {
 				vchiq_log_info(vchiq_arm_log_level, "%s interrupted", __func__);
 				DEBUG_TRACE(SERVICE_CALLBACK_LINE);
+				vchiq_service_put(service);
 				return VCHIQ_RETRY;
 			} else if (instance->closing) {
 				vchiq_log_info(vchiq_arm_log_level, "%s closing", __func__);
 				DEBUG_TRACE(SERVICE_CALLBACK_LINE);
+				vchiq_service_put(service);
 				return VCHIQ_ERROR;
 			}
 			DEBUG_TRACE(SERVICE_CALLBACK_LINE);
@@ -1137,6 +1152,7 @@ service_callback(enum vchiq_reason reason, struct vchiq_header *header,
 		header = NULL;
 	}
 	DEBUG_TRACE(SERVICE_CALLBACK_LINE);
+	vchiq_service_put(service);
 
 	if (skip_completion)
 		return VCHIQ_SUCCESS;