torture: Remove CONFIG_RCU_TORTURE_TEST_RUNNABLE, simplify code

This commit removes CONFIG_RCU_TORTURE_TEST_RUNNABLE in favor of the
already-existing rcutorture.torture_runnable kernel boot parameter.
It also converts an #ifdef into IS_ENABLED(), saving a few lines of code.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

kernel/rcu/rcutorture.c

@@ -182,12 +182,7 @@ static const char *rcu_torture_writer_state_getname(void)
 	return rcu_torture_writer_state_names[i];
 }
 
-#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
-#define RCUTORTURE_RUNNABLE_INIT 1
-#else
-#define RCUTORTURE_RUNNABLE_INIT 0
-#endif
-static int torture_runnable = RCUTORTURE_RUNNABLE_INIT;
+static int torture_runnable = IS_ENABLED(MODULE);
 module_param(torture_runnable, int, 0444);
 MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot");
 

kernel/rcu/tree_plugin.h

@@ -79,8 +79,6 @@ static void __init rcu_bootup_announce_oddness(void)
 		pr_info("\tRCU dyntick-idle grace-period acceleration is enabled.\n");
 	if (IS_ENABLED(CONFIG_PROVE_RCU))
 		pr_info("\tRCU lockdep checking is enabled.\n");
-	if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_RUNNABLE))
-		pr_info("\tRCU torture testing starts during boot.\n");
 	if (RCU_NUM_LVLS >= 4)
 		pr_info("\tFour(or more)-level hierarchy is enabled.\n");
 	if (RCU_FANOUT_LEAF != 16)

lib/Kconfig.debug

@@ -1324,23 +1324,6 @@ config RCU_TORTURE_TEST
 	  Say M if you want the RCU torture tests to build as a module.
 	  Say N if you are unsure.
 
-config RCU_TORTURE_TEST_RUNNABLE
-	bool "torture tests for RCU runnable by default"
-	depends on RCU_TORTURE_TEST = y
-	default n
-	help
-	  This option provides a way to build the RCU torture tests
-	  directly into the kernel without them starting up at boot
-	  time.  You can use /proc/sys/kernel/rcutorture_runnable
-	  to manually override this setting.  This /proc file is
-	  available only when the RCU torture tests have been built
-	  into the kernel.
-
-	  Say Y here if you want the RCU torture tests to start during
-	  boot (you probably don't).
-	  Say N here if you want the RCU torture tests to start only
-	  after being manually enabled via /proc.
-
 config RCU_TORTURE_TEST_SLOW_PREINIT
 	bool "Slow down RCU grace-period pre-initialization to expose races"
 	depends on RCU_TORTURE_TEST