rcu,cleanup: move synchronize_sched_expedited() out of sched.c

The first version of synchronize_sched_expedited() used the migration
code in the scheduler, and was therefore implemented in kernel/sched.c.
However, the more recent version of this code no longer uses the
migration code, so this commit moves it to the main RCU source files.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 0 insertions, 69 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index ae8f75a5ceb4..d1e8889872a1 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -9131,72 +9131,3 @@ struct cgroup_subsys cpuacct_subsys = {
 };
 #endif  /* CONFIG_CGROUP_CPUACCT */
 
-#ifndef CONFIG_SMP
-
-void synchronize_sched_expedited(void)
-{
-        barrier();
-}
-EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
-
-#else /* #ifndef CONFIG_SMP */
-
-static atomic_t synchronize_sched_expedited_count = ATOMIC_INIT(0);
-
-static int synchronize_sched_expedited_cpu_stop(void *data)
-{
-        /*
-         * There must be a full memory barrier on each affected CPU
-         * between the time that try_stop_cpus() is called and the
-         * time that it returns.
-         *
-         * In the current initial implementation of cpu_stop, the
-         * above condition is already met when the control reaches
-         * this point and the following smp_mb() is not strictly
-         * necessary.  Do smp_mb() anyway for documentation and
-         * robustness against future implementation changes.
-         */
-        smp_mb(); /* See above comment block. */
-        return 0;
-}
-
-/*
- * Wait for an rcu-sched grace period to elapse, but use "big hammer"
- * approach to force grace period to end quickly.  This consumes
- * significant time on all CPUs, and is thus not recommended for
- * any sort of common-case code.
- *
- * Note that it is illegal to call this function while holding any
- * lock that is acquired by a CPU-hotplug notifier.  Failing to
- * observe this restriction will result in deadlock.
- */
-void synchronize_sched_expedited(void)
-{
-        int snap, trycount = 0;
-
-        smp_mb();  /* ensure prior mod happens before capturing snap. */
-        snap = atomic_read(&synchronize_sched_expedited_count) + 1;
-        get_online_cpus();
-        while (try_stop_cpus(cpu_online_mask,
-                             synchronize_sched_expedited_cpu_stop,
-                             NULL) == -EAGAIN) {
-                put_online_cpus();
-                if (trycount++ < 10)
-                        udelay(trycount * num_online_cpus());
-                else {
-                        synchronize_sched();
-                        return;
-                }
-                if (atomic_read(&synchronize_sched_expedited_count) - snap > 0) {
-                        smp_mb(); /* ensure test happens before caller kfree */
-                        return;
-                }
-                get_online_cpus();
-        }
-        atomic_inc(&synchronize_sched_expedited_count);
-        smp_mb__after_atomic_inc(); /* ensure post-GP actions seen after GP. */
-        put_online_cpus();
-}
-EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
-
-#endif /* #else #ifndef CONFIG_SMP */