Introduce ARCH_NO_SYSDEV_OPS config option (v2)

Introduce Kconfig option allowing architectures where sysdev
operations used during system suspend, resume and shutdown have been
completely replaced with struct sycore_ops operations to avoid
building sysdev code that will never be used.

Make callbacks in struct sys_device and struct sysdev_driver depend
on ARCH_NO_SYSDEV_OPS to allows us to verify if all of the references
have been actually removed from the code the given architecture
depends on.

Make x86 select ARCH_NO_SYSDEV_OPS.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

6 files changed, 27 insertions, 5 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index d57ddd7573cc..b1cd5a96a511 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -71,6 +71,7 @@ config X86
         select GENERIC_IRQ_SHOW
         select IRQ_FORCED_THREADING
         select USE_GENERIC_SMP_HELPERS if SMP
+        select ARCH_NO_SYSDEV_OPS
 
 config INSTRUCTION_DECODER
         def_bool (KPROBES || PERF_EVENTS)
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index d57e8d0fb823..e9e5238f3106 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -168,4 +168,11 @@ config SYS_HYPERVISOR
         bool
         default n
 
+config ARCH_NO_SYSDEV_OPS
+        bool
+        ---help---
+          To be selected by architectures that don't use sysdev class or
+          sysdev driver power management (suspend/resume) and shutdown
+          operations.
+
 endmenu
diff --git a/drivers/base/sys.c b/drivers/base/sys.c
index f6fb54741602..fbe72da6c414 100644
--- a/drivers/base/sys.c
+++ b/drivers/base/sys.c
@@ -329,7 +329,7 @@ void sysdev_unregister(struct sys_device *sysdev)
 }
 
 
-
+#ifndef CONFIG_ARCH_NO_SYSDEV_OPS
 /**
  *      sysdev_shutdown - Shut down all system devices.
  *
@@ -524,6 +524,7 @@ int sysdev_resume(void)
         return 0;
 }
 EXPORT_SYMBOL_GPL(sysdev_resume);
+#endif /* CONFIG_ARCH_NO_SYSDEV_OPS */
 
 int __init system_bus_init(void)
 {
diff --git a/include/linux/device.h b/include/linux/device.h
index 144ec135875f..ab8dfc095709 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -633,8 +633,12 @@ static inline int devtmpfs_mount(const char *mountpoint) { return 0; }
 /* drivers/base/power/shutdown.c */
 extern void device_shutdown(void);
 
+#ifndef CONFIG_ARCH_NO_SYSDEV_OPS
 /* drivers/base/sys.c */
 extern void sysdev_shutdown(void);
+#else
+static inline void sysdev_shutdown(void) { }
+#endif
 
 /* debugging and troubleshooting/diagnostic helpers. */
 extern const char *dev_driver_string(const struct device *dev);
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 6618216bb973..512e09177e57 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -529,13 +529,19 @@ struct dev_power_domain {
  */
 
 #ifdef CONFIG_PM_SLEEP
-extern void device_pm_lock(void);
+#ifndef CONFIG_ARCH_NO_SYSDEV_OPS
+extern int sysdev_suspend(pm_message_t state);
 extern int sysdev_resume(void);
+#else
+static inline int sysdev_suspend(pm_message_t state) { return 0; }
+static inline int sysdev_resume(void) { return 0; }
+#endif
+
+extern void device_pm_lock(void);
 extern void dpm_resume_noirq(pm_message_t state);
 extern void dpm_resume_end(pm_message_t state);
 
 extern void device_pm_unlock(void);
-extern int sysdev_suspend(pm_message_t state);
 extern int dpm_suspend_noirq(pm_message_t state);
 extern int dpm_suspend_start(pm_message_t state);
 
diff --git a/include/linux/sysdev.h b/include/linux/sysdev.h
index 1154c29f4101..8a75da551e4e 100644
--- a/include/linux/sysdev.h
+++ b/include/linux/sysdev.h
@@ -33,12 +33,13 @@ struct sysdev_class {
         const char *name;
         struct list_head        drivers;
         struct sysdev_class_attribute **attrs;
-
+        struct kset             kset;
+#ifndef CONFIG_ARCH_NO_SYSDEV_OPS
         /* Default operations for these types of devices */
         int     (*shutdown)(struct sys_device *);
         int     (*suspend)(struct sys_device *, pm_message_t state);
         int     (*resume)(struct sys_device *);
-        struct kset             kset;
+#endif
 };
 
 struct sysdev_class_attribute {
@@ -76,9 +77,11 @@ struct sysdev_driver {
         struct list_head        entry;
         int     (*add)(struct sys_device *);
         int     (*remove)(struct sys_device *);
+#ifndef CONFIG_ARCH_NO_SYSDEV_OPS
         int     (*shutdown)(struct sys_device *);
         int     (*suspend)(struct sys_device *, pm_message_t state);
         int     (*resume)(struct sys_device *);
+#endif
 };