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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: 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/20151117170523.GA13955@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Oleg Nesterov 2015-11-17 18:05:23 +01:00 committed by Ingo Molnar
parent 6a19005157
commit 1b034bd989
2 changed files with 17 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
include/linux/stop_machine.h
View File

@ -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,

16
kernel/stop_machine.c
View File

@ -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 */