Simplify stop_machine
stop_machine creates a kthread which creates kernel threads. We can
create those threads directly and simplify things a little. Some care
must be taken with CPU hotunplug, which has special needs, but that code
seems more robust than it was in the past.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 10ba5f1..cf79bb9 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -216,7 +216,6 @@
static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
{
int err, nr_calls = 0;
- struct task_struct *p;
cpumask_t old_allowed, tmp;
void *hcpu = (void *)(long)cpu;
unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
@@ -250,19 +249,15 @@
cpu_clear(cpu, tmp);
set_cpus_allowed_ptr(current, &tmp);
- p = __stop_machine_run(take_cpu_down, &tcd_param, cpu);
+ err = __stop_machine_run(take_cpu_down, &tcd_param, cpu);
- if (IS_ERR(p) || cpu_online(cpu)) {
+ if (err || cpu_online(cpu)) {
/* CPU didn't die: tell everyone. Can't complain. */
if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
hcpu) == NOTIFY_BAD)
BUG();
- if (IS_ERR(p)) {
- err = PTR_ERR(p);
- goto out_allowed;
- }
- goto out_thread;
+ goto out_allowed;
}
/* Wait for it to sleep (leaving idle task). */
@@ -279,8 +274,6 @@
check_for_tasks(cpu);
-out_thread:
- err = kthread_stop(p);
out_allowed:
set_cpus_allowed_ptr(current, &old_allowed);
out_release:
