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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 24 May 2017 10:15:27 +0200
Subject: [PATCH 16/32] powerpc/powernv: Use stop_machine_cpuslocked()
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
---
arch/powerpc/platforms/powernv/subcore.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/arch/powerpc/platforms/powernv/subcore.c
+++ b/arch/powerpc/platforms/powernv/subcore.c
@@ -348,7 +348,7 @@ static int set_subcores_per_core(int new
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
/* 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;
}
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