| Date | Wed, 24 May 2017 10:15:23 +0200 | From | Thomas Gleixner <> | Subject | [patch V3 12/32] hwtracing/coresight-etm4x: Use cpuhp_setup_state_nocalls_cpuslocked() |
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arm-kernel@lists.infradead.org
--- drivers/hwtracing/coresight/coresight-etm4x.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)
--- a/drivers/hwtracing/coresight/coresight-etm4x.c +++ b/drivers/hwtracing/coresight/coresight-etm4x.c @@ -371,7 +371,7 @@ static void etm4_disable_sysfs(struct co * 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 co 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 drvdata->cpu = pdata ? pdata->cpu : 0; - get_online_cpus(); + cpus_read_lock(); etmdrvdata[drvdata->cpu] = drvdata; if (smp_call_function_single(drvdata->cpu, @@ -990,18 +990,18 @@ static int etm4_probe(struct amba_device 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; } - put_online_cpus(); + cpus_read_unlock(); if (etm4_arch_supported(drvdata->arch) == false) { ret = -EINVAL;
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