linux-kernel - [tip:smp/hotplug] perf/core: Remove redundant get_online

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Date:   Thu, 20 Apr 2017 04:28:35 -0700
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     bigeasy@...utronix.de, peterz@...radead.org, rostedt@...dmis.org,
        linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...nel.org,
        hpa@...or.com
Subject: [tip:smp/hotplug] perf/core: Remove redundant get_online_cpus()

Commit-ID:  3e27bdd5a4fc7954af4027f1a77e9556deed653d
Gitweb:     http://git.kernel.org/tip/3e27bdd5a4fc7954af4027f1a77e9556deed653d
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Tue, 18 Apr 2017 19:05:02 +0200
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Thu, 20 Apr 2017 13:08:56 +0200

perf/core: Remove redundant get_online_cpus()

SyS_perf_event_open() calls get_online_cpus() and eventually invokes
swevent_hlist_get() which does it again. 

All callchains leading to swevent_hlist_get() originate from
SyS_perf_event_open() so the extra protection is redundant.

Remove it.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Sebastian Siewior <bigeasy@...utronix.de>
Cc: Steven Rostedt <rostedt@...dmis.org>
Link: http://lkml.kernel.org/r/20170418170554.043759892@linutronix.de

---
 kernel/events/core.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index ff01cba..634dd95 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7592,7 +7592,6 @@ static int swevent_hlist_get(void)
 {
 	int err, cpu, failed_cpu;
 
-	get_online_cpus();
 	for_each_possible_cpu(cpu) {
 		err = swevent_hlist_get_cpu(cpu);
 		if (err) {
@@ -7600,8 +7599,6 @@ static int swevent_hlist_get(void)
 			goto fail;
 		}
 	}
-	put_online_cpus();
-
 	return 0;
 fail:
 	for_each_possible_cpu(cpu) {
@@ -7609,8 +7606,6 @@ fail:
 			break;
 		swevent_hlist_put_cpu(cpu);
 	}
-
-	put_online_cpus();
 	return err;
 }