[PATCH 14/21] fault-injection: cpu: Convert to hotplug state machine

Sebastian Andrzej Siewior
2016-09-06T17:06:23Z

Install the callbacks via the state machine.
This is just temporary. The longterm plan is to create a debugfs interface
where we can put the CPUs up and down from any given point to any given
point. So even if the conversations is not the prettiest - it is just
temporary.

Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
include/linux/cpuhotplug.h | 1 +
lib/cpu-notifier-error-inject.c | 46 +++++++++++++++++++++++++++++++++++------
2 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 0c33668d1626..4cbf88c955d6 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -43,6 +43,7 @@ enum cpuhp_state {
CPUHP_ARM_SHMOBILE_SCU_PREPARE,
CPUHP_SH_SH3X_PREPARE,
CPUHP_X86_MICRCODE_PREPARE,
+ CPUHP_NOTF_ERR_INJ_PREPARE,
CPUHP_TIMERS_DEAD,
CPUHP_BRINGUP_CPU,
CPUHP_AP_IDLE_DEAD,
diff --git a/lib/cpu-notifier-error-inject.c b/lib/cpu-notifier-error-inject.c
index 707ca24f7b18..0e2c9a1e958a 100644
--- a/lib/cpu-notifier-error-inject.c
+++ b/lib/cpu-notifier-error-inject.c
@@ -8,16 +8,47 @@ static int priority;
module_param(priority, int, 0);
MODULE_PARM_DESC(priority, "specify cpu notifier priority");

+#define UP_PREPARE 0
+#define UP_PREPARE_FROZEN 0
+#define DOWN_PREPARE 0
+#define DOWN_PREPARE_FROZEN 0
+
static struct notifier_err_inject cpu_notifier_err_inject = {
.actions = {
- { NOTIFIER_ERR_INJECT_ACTION(CPU_UP_PREPARE) },
- { NOTIFIER_ERR_INJECT_ACTION(CPU_UP_PREPARE_FROZEN) },
- { NOTIFIER_ERR_INJECT_ACTION(CPU_DOWN_PREPARE) },
- { NOTIFIER_ERR_INJECT_ACTION(CPU_DOWN_PREPARE_FROZEN) },
+ { NOTIFIER_ERR_INJECT_ACTION(UP_PREPARE) },
+ { NOTIFIER_ERR_INJECT_ACTION(UP_PREPARE_FROZEN) },
+ { NOTIFIER_ERR_INJECT_ACTION(DOWN_PREPARE) },
+ { NOTIFIER_ERR_INJECT_ACTION(DOWN_PREPARE_FROZEN) },
{}
}
};

+static int notf_err_handle(struct notifier_err_inject_action *action)
+{
+ int ret;
+
+ ret = action->error;
+ if (ret)
+ pr_info("Injecting error (%d) to %s\n", ret, action->name);
+ return ret;
+}
+
+static int notf_err_inj_up_prepare(unsigned int cpu)
+{
+ if (!cpuhp_tasks_frozen)
+ return notf_err_handle(&cpu_notifier_err_inject.actions[0]);
+ else
+ return notf_err_handle(&cpu_notifier_err_inject.actions[1]);
+}
+
+static int notf_err_inj_dead(unsigned int cpu)
+{
+ if (!cpuhp_tasks_frozen)
+ return notf_err_handle(&cpu_notifier_err_inject.actions[2]);
+ else
+ return notf_err_handle(&cpu_notifier_err_inject.actions[3]);
+}
+
static struct dentry *dir;

static int err_inject_init(void)
@@ -29,7 +60,10 @@ static int err_inject_init(void)
if (IS_ERR(dir))
return PTR_ERR(dir);

- err = register_hotcpu_notifier(&cpu_notifier_err_inject.nb);
+ err = cpuhp_setup_state_nocalls(CPUHP_NOTF_ERR_INJ_PREPARE,
+ "cpu-err-notif:prepare",
+ notf_err_inj_up_prepare,
+ notf_err_inj_dead);
if (err)
debugfs_remove_recursive(dir);

@@ -38,7 +72,7 @@ static int err_inject_init(void)

static void err_inject_exit(void)
{
- unregister_hotcpu_notifier(&cpu_notifier_err_inject.nb);
+ cpuhp_remove_state_nocalls(CPUHP_NOTF_ERR_INJ_PREPARE);
debugfs_remove_recursive(dir);
}

--
2.9.3