| 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; |
| } |