From: Sebastian Andrzej Siewior <[email protected]> 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 <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: Mathieu Poirier <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: [email protected] --- 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;
