linux-kernel - [PATCH 3/7] smp: use __cpumask_set_cpu in on_each_cpu

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Message-Id: <20180924183759.23955-4-riel@surriel.com>
Date:   Mon, 24 Sep 2018 14:37:55 -0400
From:   Rik van Riel <riel@...riel.com>
To:     linux-kernel@...r.kernel.org
Cc:     peterz@...radead.org, kernel-team@...com, songliubraving@...com,
        mingo@...nel.org, will.deacon@....com, hpa@...or.com,
        luto@...nel.org, npiggin@...il.com, Rik van Riel <riel@...riel.com>
Subject: [PATCH 3/7] 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.

Suggested-by: Peter Zijlstra <peterz@...radead.org>
Signed-off-by: Rik van Riel <riel@...riel.com>
Reviewed-by: Andy Lutomirski <luto@...nel.org>
---
 kernel/smp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index 084c8b3a2681..2dbc842dd385 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -680,7 +680,7 @@ 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);
-- 
2.17.1