stop_machine(): stop_machine_run() changed to use cpu mask
Instead of a "cpu" arg with magic values NR_CPUS (any cpu) and ~0 (all
cpus), pass a cpumask_t. Allow NULL for the common case (where we
don't care which CPU the function is run on): temporary cpumask_t's
are usually considered bad for stack space.
This deprecates stop_machine_run, to be removed soon when all the
callers are dead.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 35882dc..e446c7c 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -100,7 +100,7 @@
return 0;
}
-int __stop_machine_run(int (*fn)(void *), void *data, unsigned int cpu)
+int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
{
int i, err;
struct stop_machine_data active, idle;
@@ -112,10 +112,6 @@
idle.fn = chill;
idle.data = NULL;
- /* If they don't care which cpu fn runs on, just pick one. */
- if (cpu == NR_CPUS)
- cpu = any_online_cpu(cpu_online_map);
-
/* This could be too big for stack on large machines. */
threads = kcalloc(NR_CPUS, sizeof(threads[0]), GFP_KERNEL);
if (!threads)
@@ -128,13 +124,16 @@
set_state(STOPMACHINE_PREPARE);
for_each_online_cpu(i) {
- struct stop_machine_data *smdata;
+ struct stop_machine_data *smdata = &idle;
struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
- if (cpu == ALL_CPUS || i == cpu)
- smdata = &active;
- else
- smdata = &idle;
+ if (!cpus) {
+ if (i == first_cpu(cpu_online_map))
+ smdata = &active;
+ } else {
+ if (cpu_isset(i, *cpus))
+ smdata = &active;
+ }
threads[i] = kthread_create((void *)stop_cpu, smdata, "kstop%u",
i);
@@ -154,7 +153,7 @@
/* We've created all the threads. Wake them all: hold this CPU so one
* doesn't hit this CPU until we're ready. */
- cpu = get_cpu();
+ get_cpu();
for_each_online_cpu(i)
wake_up_process(threads[i]);
@@ -177,15 +176,15 @@
return err;
}
-int stop_machine_run(int (*fn)(void *), void *data, unsigned int cpu)
+int stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
{
int ret;
/* No CPUs can come up or down during this. */
get_online_cpus();
- ret = __stop_machine_run(fn, data, cpu);
+ ret = __stop_machine(fn, data, cpus);
put_online_cpus();
return ret;
}
-EXPORT_SYMBOL_GPL(stop_machine_run);
+EXPORT_SYMBOL_GPL(stop_machine);