[tip:smp/hotplug] hwtracing/coresight-etm4x: Use cpuhp_setup_state_nocalls_cpuslocked()

[tip-bot for Sebastian Andrzej Siewior]

Commit-ID:  91e555edde960481085a8a69ac32726a9f6df0c9
Gitweb:     http://git.kernel.org/tip/91e555edde960481085a8a69ac32726a9f6df0c9
Author:     Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
AuthorDate: Tue, 18 Apr 2017 19:04:51 +0200
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 20 Apr 2017 13:08:53 +0200

hwtracing/coresight-etm4x: Use cpuhp_setup_state_nocalls_cpuslocked()

etm_probe4() holds get_online_cpus() while invoking
cpuhp_setup_state_nocalls().

cpuhp_setup_state_nocalls() 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_nocalls_cpuslocked() to avoid the nested call.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20170418170553.108514162@xxxxxxxxxxxxx
---
 drivers/hwtracing/coresight/coresight-etm4x.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index d1340fb..bd3046c 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -990,12 +990,12 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id)
 		dev_err(dev, "ETM arch init failed\n");
 
 	if (!etm4_count++) {
-		cpuhp_setup_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING,
-					  "arm/coresight4:starting",
-					  etm4_starting_cpu, etm4_dying_cpu);
-		ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
-						"arm/coresight4:online",
-						etm4_online_cpu, NULL);
+		cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING,
+						     "arm/coresight4:starting",
+						     etm4_starting_cpu, etm4_dying_cpu);
+		ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
+							   "arm/coresight4:online",
+							   etm4_online_cpu, NULL);
 		if (ret < 0)
 			goto err_arch_supported;
 		hp_online = ret;