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powerpc/powernv: Use stop_machine_cpuslocked()

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set_subcores_per_core() holds get_online_cpus() while invoking stop_machine().

stop_machine() invokes get_online_cpus() as well. This is correct, but
prevents the conversion of the hotplug locking to a percpu rwsem.

Use stop_machine_cpuslocked() to avoid the nested call. Convert
*_online_cpus() to the new interfaces while at it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/20170524081548.331016542@linutronix.de
This commit is contained in:
Sebastian Andrzej Siewior 2017-05-24 10:15:27 +02:00 committed by Thomas Gleixner
parent 2337e879e8
commit f9a69931c3
1 changed files with 4 additions and 3 deletions
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7
arch/powerpc/platforms/powernv/subcore.c
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@ -348,7 +348,7 @@ static int set_subcores_per_core(int new_mode)
state->master = 0;
}
get_online_cpus();
cpus_read_lock();
/* This cpu will update the globals before exiting stop machine */
this_cpu_ptr(&split_state)->master = 1;
@ -356,9 +356,10 @@ static int set_subcores_per_core(int new_mode)
/* Ensure state is consistent before we call the other cpus */
mb();
stop_machine(cpu_update_split_mode, &new_mode, cpu_online_mask);
stop_machine_cpuslocked(cpu_update_split_mode, &new_mode,
cpu_online_mask);
put_online_cpus();
cpus_read_unlock();
return 0;
}