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| author | Oleg Nesterov <oleg@redhat.com> | 2015-11-15 19:33:14 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-11-23 08:48:18 (GMT) |
| commit | 6a19005157c464b47b2082f2617d12bc11198a0d (patch) | |
| tree | 90b75567427d005de8b2032fe2005cd08153f40c | |
| parent | 64038f292a1b33c7d46bd11f62f7798101152c00 (diff) | |
| download | linux-6a19005157c464b47b2082f2617d12bc11198a0d.tar.xz | |
stop_machine: Don't disable preemption in stop_two_cpus()
Now that stop_two_cpus() path does not check cpu_active() we can remove
preempt_disable(), it was only needed to ensure that stop_machine() can
not be called after we observe cpu_active() == T and before we queue the
new work.
Also, turn the pointless and confusing ->executed check into WARN_ON().
We know that both works must be executed, otherwise we have a bug. And
in fact I think that done->executed should die, 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/20151115193314.GA8249@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | kernel/stop_machine.c | 11 |
1 files changed, 3 insertions, 8 deletions
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index 1a66a95..17f01a9 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -258,7 +258,6 @@ int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void * struct cpu_stop_work work1, work2; struct multi_stop_data msdata; - preempt_disable(); msdata = (struct multi_stop_data){ .fn = fn, .data = arg, @@ -277,16 +276,12 @@ int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void * if (cpu1 > cpu2) swap(cpu1, cpu2); - if (cpu_stop_queue_two_works(cpu1, &work1, cpu2, &work2)) { - preempt_enable(); + if (cpu_stop_queue_two_works(cpu1, &work1, cpu2, &work2)) return -ENOENT; - } - - preempt_enable(); wait_for_completion(&done.completion); - - return done.executed ? done.ret : -ENOENT; + WARN_ON(!done.executed); + return done.ret; } /** |