[PATCH tip/core/rcu 02/17] torture: Bring any extra CPUs online during kernel startup

["Paul E. McKenney" <paulmck@linux.ibm.com>]

From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

Currently, the torture scripts rely on the initrd/init script to bring
any extra CPUs online, for example, in the case where the kernel and
qemu have different ideas about how many CPUs are present.  This works,
but is an unnecessary dependency on initrd, which needs to vary depending
on the distro.  This commit therefore causes torture_onoff() to check
for additional CPUs, attempting to bring any found online. Errors are
ignored, just as they are by the initrd/init script.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 kernel/torture.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/kernel/torture.c b/kernel/torture.c
index 17d91f5fba2a..9410d1bf84d6 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -194,11 +194,23 @@ torture_onoff(void *arg)
 	int cpu;
 	int maxcpu = -1;
 	DEFINE_TORTURE_RANDOM(rand);
+	int ret;
 
 	VERBOSE_TOROUT_STRING("torture_onoff task started");
 	for_each_online_cpu(cpu)
 		maxcpu = cpu;
 	WARN_ON(maxcpu < 0);
+	if (!IS_MODULE(CONFIG_TORTURE_TEST))
+		for_each_possible_cpu(cpu) {
+			if (cpu_online(cpu))
+				continue;
+			ret = cpu_up(cpu);
+			if (ret && verbose) {
+				pr_alert("%s" TORTURE_FLAG
+					 "%s: Initial online %d: errno %d\n",
+					 __func__, torture_type, cpu, ret);
+			}
+		}
 
 	if (maxcpu == 0) {
 		VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
-- 
2.17.1