smp: use __cpumask_set_cpu in on_each_cpu_cond

The code in on_each_cpu_cond sets CPUs in a locally allocated bitmask,
which should never be used by other CPUs simultaneously. There is no
need to use locked memory accesses to set the bits in this bitmap.

Switch to __cpumask_set_cpu.

Cc: npiggin@gmail.com
Cc: mingo@kernel.org
Cc: will.deacon@arm.com
Cc: songliubraving@fb.com
Cc: kernel-team@fb.com
Cc: hpa@zytor.com
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180926035844.1420-4-riel@surriel.com

diff --git a/kernel/smp.c b/kernel/smp.c
index d86eec5..a7d4f9f 100644 (file)
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -682,7 +682,7 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
                preempt_disable();
                for_each_online_cpu(cpu)
                        if (cond_func(cpu, info))
-                               cpumask_set_cpu(cpu, cpus);
+                               __cpumask_set_cpu(cpu, cpus);
                on_each_cpu_mask(cpus, func, info, wait);
                preempt_enable();
                free_cpumask_var(cpus);