[tip:sched/core] stop_machine: Kill cpu_stop_done->executed

tip-bot for Oleg Nesterov
2015-11-23T16:23:49Z

Commit-ID: 6fa3b826bcb3309157166e6e523a4be236fe267a
Gitweb: http://git.kernel.org/tip/6fa3b826bcb3309157166e6e523a4be236fe267a
Author: Oleg Nesterov <oleg@redhat.com>
AuthorDate: Sun, 15 Nov 2015 20:33:26 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 23 Nov 2015 09:48:19 +0100

stop_machine: Kill cpu_stop_done->executed

Now that cpu_stop_done->executed becomes write-only (ignoring WARN_ON()
checks) we can remove it.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Milos Vyletel <milos@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20151115193326.GA8269@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/stop_machine.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index ed2019a..09eb83f 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -28,7 +28,6 @@
*/
struct cpu_stop_done {
atomic_t nr_todo; /* nr left to execute */
- bool executed; /* actually executed? */
int ret; /* collected return value */
struct completion completion; /* fired if nr_todo reaches 0 */
};
@@ -63,11 +62,9 @@ static void cpu_stop_init_done(struct cpu_stop_done *done, unsigned int nr_todo)
}

/* signal completion unless @done is NULL */
-static void cpu_stop_signal_done(struct cpu_stop_done *done, bool executed)
+static void cpu_stop_signal_done(struct cpu_stop_done *done)
{
if (done) {
- if (executed)
- done->executed = true;
if (atomic_dec_and_test(&done->nr_todo))
complete(&done->completion);
}
@@ -92,7 +89,7 @@ static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)
if (enabled)
__cpu_stop_queue_work(stopper, work);
else
- cpu_stop_signal_done(work->done, false);
+ cpu_stop_signal_done(work->done);
spin_unlock_irqrestore(&stopper->lock, flags);

return enabled;
@@ -131,7 +128,6 @@ int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg)
if (!cpu_stop_queue_work(cpu, &work))
return -ENOENT;
wait_for_completion(&done.completion);
- WARN_ON(!done.executed);
return done.ret;
}

@@ -286,7 +282,6 @@ int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void *
return -ENOENT;

wait_for_completion(&done.completion);
- WARN_ON(!done.executed);
return done.ret;
}

@@ -354,7 +349,6 @@ static int __stop_cpus(const struct cpumask *cpumask,
if (!queue_stop_cpus_work(cpumask, fn, arg, &done))
return -ENOENT;
wait_for_completion(&done.completion);
- WARN_ON(!done.executed);
return done.ret;
}

@@ -467,6 +461,7 @@ repeat:
ret = fn(arg);
if (ret && done)
done->ret = ret;
+ cpu_stop_signal_done(done);

/* restore preemption and check it's still balanced */
preempt_enable();
@@ -475,7 +470,6 @@ repeat:
kallsyms_lookup((unsigned long)fn, NULL, NULL, NULL,
ksym_buf), arg);

- cpu_stop_signal_done(done, true);
goto repeat;
}
}