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Commit 1b034bd9 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Ingo Molnar
Browse files

stop_machine: Make cpu_stop_queue_work() and stop_one_cpu_nowait() return bool 



Change cpu_stop_queue_work() to return true if the work was queued and
change stop_one_cpu_nowait() to return the result of cpu_stop_queue_work().
This makes it more useful, for example now you can alloc cpu_stop_work for
stop_one_cpu_nowait() and free it in the callback or if stop_one_cpu_nowait()
fails, currently this is impossible because you can't know if @FN will be
called or not.

Also, this allows to kill cpu_stop_done->executed, see the next changes.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarTejun 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/20151117170523.GA13955@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 6a190051

include/linux/stop_machine.h

+5 −2
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ struct cpu_stop_work { 


int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg);

int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void *arg);

void stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,

bool stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,

			 struct cpu_stop_work *work_buf);

int stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg);

int try_stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg);
@@ -65,7 +65,7 @@ static void stop_one_cpu_nowait_workfn(struct work_struct *work) 
	preempt_enable();

}



static inline void stop_one_cpu_nowait(unsigned int cpu,

static inline bool stop_one_cpu_nowait(unsigned int cpu,

				       cpu_stop_fn_t fn, void *arg,

				       struct cpu_stop_work *work_buf)

{
@@ -74,7 +74,10 @@ static inline void stop_one_cpu_nowait(unsigned int cpu, 
		work_buf->fn = fn;

		work_buf->arg = arg;

		schedule_work(&work_buf->work);

		return true;

	}



	return false;

}



static inline int stop_cpus(const struct cpumask *cpumask,

kernel/stop_machine.c

+12 −4
Original line number Diff line number Diff line
@@ -81,17 +81,21 @@ static void __cpu_stop_queue_work(struct cpu_stopper *stopper, 
}



/* queue @work to @stopper.  if offline, @work is completed immediately */

static void cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)

static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)

{

	struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);

	unsigned long flags;

	bool enabled;



	spin_lock_irqsave(&stopper->lock, flags);

	if (stopper->enabled)

	enabled = stopper->enabled;

	if (enabled)

		__cpu_stop_queue_work(stopper, work);

	else

		cpu_stop_signal_done(work->done, false);

	spin_unlock_irqrestore(&stopper->lock, flags);



	return enabled;

}



/**
@@ -297,12 +301,16 @@ int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void * 
 *

 * CONTEXT:

 * Don't care.

 *

 * RETURNS:

 * true if cpu_stop_work was queued successfully and @fn will be called,

 * false otherwise.

 */

void stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,

bool stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,

			struct cpu_stop_work *work_buf)

{

	*work_buf = (struct cpu_stop_work){ .fn = fn, .arg = arg, };

	cpu_stop_queue_work(cpu, work_buf);

	return cpu_stop_queue_work(cpu, work_buf);

}



/* static data for stop_cpus */