[patch 08/20] hwtracing/coresight-etm3x: Use the locked version of cpuhp_setup_state_nocalls()

From: Thomas Gleixner
Date: Sat Apr 15 2017 - 13:34:41 EST


From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>

etm_probe() 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_locked() 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: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx

---
drivers/hwtracing/coresight/coresight-etm3x.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
index a51b6b64ecdf..0887265f361d 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x.c
@@ -803,12 +803,12 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id)
dev_err(dev, "ETM arch init failed\n");

if (!etm_count++) {
- cpuhp_setup_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING,
- "arm/coresight:starting",
- etm_starting_cpu, etm_dying_cpu);
- ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
- "arm/coresight:online",
- etm_online_cpu, NULL);
+ cpuhp_setup_state_nocalls_locked(CPUHP_AP_ARM_CORESIGHT_STARTING,
+ "arm/coresight:starting",
+ etm_starting_cpu, etm_dying_cpu);
+ ret = cpuhp_setup_state_nocalls_locked(CPUHP_AP_ONLINE_DYN,
+ "arm/coresight:online",
+ etm_online_cpu, NULL);
if (ret < 0)
goto err_arch_supported;
hp_online = ret;
--
2.11.0