linux-kernel - [tip:x86/mm] smp: use __cpumask_set_cpu in on_each_cpu

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Message-ID: <tip-c3f7f2c7eba1a53d2e5ffbc2dcc9a20c5f094890@git.kernel.org>
Date:   Tue, 9 Oct 2018 07:59:15 -0700
From:   tip-bot for Rik van Riel <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tglx@...utronix.de, riel@...riel.com, peterz@...radead.org,
        linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
        luto@...nel.org
Subject: [tip:x86/mm] smp: use __cpumask_set_cpu in on_each_cpu_cond

Commit-ID:  c3f7f2c7eba1a53d2e5ffbc2dcc9a20c5f094890
Gitweb:     https://git.kernel.org/tip/c3f7f2c7eba1a53d2e5ffbc2dcc9a20c5f094890
Author:     Rik van Riel <riel@...riel.com>
AuthorDate: Tue, 25 Sep 2018 23:58:40 -0400
Committer:  Peter Zijlstra <peterz@...radead.org>
CommitDate: Tue, 9 Oct 2018 16:51:11 +0200

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@...il.com
Cc: mingo@...nel.org
Cc: will.deacon@....com
Cc: songliubraving@...com
Cc: kernel-team@...com
Cc: hpa@...or.com
Suggested-by: Peter Zijlstra <peterz@...radead.org>
Signed-off-by: Rik van Riel <riel@...riel.com>
Reviewed-by: Andy Lutomirski <luto@...nel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: http://lkml.kernel.org/r/20180926035844.1420-4-riel@surriel.com
---
 kernel/smp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index d86eec5f51c1..a7d4f9f50a49 100644
--- 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);