linux-kernel - [tip:sched/core] stop_machine: Kill cpu_stop

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Date:	Mon, 23 Nov 2015 08:23:11 -0800
From:	tip-bot for Oleg Nesterov <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	oleg@...hat.com, tglx@...utronix.de, mingo@...nel.org,
	torvalds@...ux-foundation.org, prarit@...hat.com,
	linux-kernel@...r.kernel.org, tj@...nel.org, hpa@...or.com,
	efault@....de, milos@...hat.com, peterz@...radead.org
Subject: [tip:sched/core] stop_machine: Kill cpu_stop_done->executed

Commit-ID:  6fa3b826bcb3309157166e6e523a4be236fe267a
Gitweb:     http://git.kernel.org/tip/6fa3b826bcb3309157166e6e523a4be236fe267a
Author:     Oleg Nesterov <oleg@...hat.com>
AuthorDate: Sun, 15 Nov 2015 20:33:26 +0100
Committer:  Ingo Molnar <mingo@...nel.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@...hat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Acked-by: Tejun Heo <tj@...nel.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Mike Galbraith <efault@....de>
Cc: Milos Vyletel <milos@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Prarit Bhargava <prarit@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/20151115193326.GA8269@redhat.com
Signed-off-by: Ingo Molnar <mingo@...nel.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;
 	}
 }
--
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