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Commit e9f5d63f authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner
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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. Convert *_online_cpus() to the new interfaces while at it.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170524081547.983493849@linutronix.de
parent e560c89c

drivers/hwtracing/coresight/coresight-etm4x.c

+10 −10
Original line number Diff line number Diff line
@@ -371,7 +371,7 @@ static void etm4_disable_sysfs(struct coresight_device *csdev) 
	 * after cpu online mask indicates the cpu is offline but before the

	 * DYING hotplug callback is serviced by the ETM driver.

	 */

	get_online_cpus();

	cpus_read_lock();

	spin_lock(&drvdata->spinlock);



	/*
@@ -381,7 +381,7 @@ static void etm4_disable_sysfs(struct coresight_device *csdev) 
	smp_call_function_single(drvdata->cpu, etm4_disable_hw, drvdata, 1);



	spin_unlock(&drvdata->spinlock);

	put_online_cpus();

	cpus_read_unlock();



	dev_info(drvdata->dev, "ETM tracing disabled\n");

}
@@ -982,7 +982,7 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) 


	drvdata->cpu = pdata ? pdata->cpu : 0;



	get_online_cpus();

	cpus_read_lock();

	etmdrvdata[drvdata->cpu] = drvdata;



	if (smp_call_function_single(drvdata->cpu,
@@ -990,10 +990,10 @@ 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,

		cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING,

						     "arm/coresight4:starting",

						     etm4_starting_cpu, etm4_dying_cpu);

		ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,

		ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,

							   "arm/coresight4:online",

							   etm4_online_cpu, NULL);

		if (ret < 0)
@@ -1001,7 +1001,7 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) 
		hp_online = ret;

	}



	put_online_cpus();

	cpus_read_unlock();



	if (etm4_arch_supported(drvdata->arch) == false) {

		ret = -EINVAL;