linux-kernel - [tip:smp/hotplug] perf/x86/intel/cqm: Use cpuhp_setup_state

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Message-ID: <tip-88840592a3483951be52f3ed35f4c4348dc9eed9@git.kernel.org>
Date:   Thu, 20 Apr 2017 04:23:27 -0700
From:   tip-bot for Sebastian Andrzej Siewior <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tglx@...utronix.de, bigeasy@...utronix.de, fenghua.yu@...el.com,
        peterz@...radead.org, mingo@...nel.org, rostedt@...dmis.org,
        hpa@...or.com, linux-kernel@...r.kernel.org
Subject: [tip:smp/hotplug] perf/x86/intel/cqm: Use
 cpuhp_setup_state_cpuslocked()

Commit-ID:  88840592a3483951be52f3ed35f4c4348dc9eed9
Gitweb:     http://git.kernel.org/tip/88840592a3483951be52f3ed35f4c4348dc9eed9
Author:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>
AuthorDate: Tue, 18 Apr 2017 19:04:52 +0200
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Thu, 20 Apr 2017 13:08:53 +0200

perf/x86/intel/cqm: Use cpuhp_setup_state_cpuslocked()

intel_cqm_init() holds get_online_cpus() while registerring the hotplug
callbacks.

cpuhp_setup_state() invokes get_online_cpus() as well. This is correct, but
prevents the conversion of the hotplug locking to a percpu rwsem.

Use cpuhp_setup_state_cpuslocked() to avoid the nested call.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: Steven Rostedt <rostedt@...dmis.org>
Link: http://lkml.kernel.org/r/20170418170553.191578891@linutronix.de
---
 arch/x86/events/intel/cqm.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/events/intel/cqm.c b/arch/x86/events/intel/cqm.c
index 8c00dc0..2d4a842 100644
--- a/arch/x86/events/intel/cqm.c
+++ b/arch/x86/events/intel/cqm.c
@@ -1746,12 +1746,12 @@ static int __init intel_cqm_init(void)
 	 * Setup the hot cpu notifier once we are sure cqm
 	 * is enabled to avoid notifier leak.
 	 */
-	cpuhp_setup_state(CPUHP_AP_PERF_X86_CQM_STARTING,
-			  "perf/x86/cqm:starting",
-			  intel_cqm_cpu_starting, NULL);
-	cpuhp_setup_state(CPUHP_AP_PERF_X86_CQM_ONLINE, "perf/x86/cqm:online",
-			  NULL, intel_cqm_cpu_exit);
-
+	cpuhp_setup_state_cpuslocked(CPUHP_AP_PERF_X86_CQM_STARTING,
+				     "perf/x86/cqm:starting",
+				     intel_cqm_cpu_starting, NULL);
+	cpuhp_setup_state_cpuslocked(CPUHP_AP_PERF_X86_CQM_ONLINE,
+				     "perf/x86/cqm:online",
+				     NULL, intel_cqm_cpu_exit);
 out:
 	put_online_cpus();