[PATCH 4.4 26/47] PM / sleep: wakeup: Fix build error caused by missing SRCU support

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: zhangyi (F) <yi.zhang@xxxxxxxxxx>

commit 3df6f61fff49632492490fb6e42646b803a9958a upstream.

Commit ea0212f40c6 (power: auto select CONFIG_SRCU) made the code in
drivers/base/power/wakeup.c use SRCU instead of RCU, but it forgot to
select CONFIG_SRCU in Kconfig, which leads to the following build
error if CONFIG_SRCU is not selected somewhere else:

drivers/built-in.o: In function `wakeup_source_remove':
(.text+0x3c6fc): undefined reference to `synchronize_srcu'
drivers/built-in.o: In function `pm_print_active_wakeup_sources':
(.text+0x3c7a8): undefined reference to `__srcu_read_lock'
drivers/built-in.o: In function `pm_print_active_wakeup_sources':
(.text+0x3c84c): undefined reference to `__srcu_read_unlock'
drivers/built-in.o: In function `device_wakeup_arm_wake_irqs':
(.text+0x3d1d8): undefined reference to `__srcu_read_lock'
drivers/built-in.o: In function `device_wakeup_arm_wake_irqs':
(.text+0x3d228): undefined reference to `__srcu_read_unlock'
drivers/built-in.o: In function `device_wakeup_disarm_wake_irqs':
(.text+0x3d24c): undefined reference to `__srcu_read_lock'
drivers/built-in.o: In function `device_wakeup_disarm_wake_irqs':
(.text+0x3d29c): undefined reference to `__srcu_read_unlock'
drivers/built-in.o:(.data+0x4158): undefined reference to `process_srcu'

Fix this error by selecting CONFIG_SRCU when PM_SLEEP is enabled.

Fixes: ea0212f40c6 (power: auto select CONFIG_SRCU)
Cc: 4.2+ <stable@xxxxxxxxxxxxxxx> # 4.2+
Signed-off-by: zhangyi (F) <yi.zhang@xxxxxxxxxx>
[ rjw: Minor subject/changelog fixups ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/power/Kconfig |    1 +
 1 file changed, 1 insertion(+)

--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -105,6 +105,7 @@ config PM_SLEEP
 	def_bool y
 	depends on SUSPEND || HIBERNATE_CALLBACKS
 	select PM
+	select SRCU
 
 config PM_SLEEP_SMP
 	def_bool y