Re: [PATCH] leds/trigger/cpu: move from CPU_STARTING to ONLINE level

From: Jacek Anaszewski
Date: Thu Jul 21 2016 - 02:49:00 EST


Hi Sebastian,

On 07/20/2016 05:24 PM, Sebastian Andrzej Siewior wrote:
There is no need the ledtriger to be called *that* early in the hotplug
process (+ with disabled interrupts). As explained by Jacek Anaszewski [0]
there is no need for it.
Therefore this patch moves it to the ONLINE/PREPARE_DOWN level using the
dynamic registration for the id.

[0] https://lkml.kernel.org/r/578C92BC.2070603@xxxxxxxxxxx

Cc: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Richard Purdie <rpurdie@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-leds@xxxxxxxxxxxxxxx
Cc: rt@xxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
drivers/leds/trigger/ledtrig-cpu.c | 16 ++++++++--------
include/linux/cpuhotplug.h | 1 -
2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/leds/trigger/ledtrig-cpu.c b/drivers/leds/trigger/ledtrig-cpu.c
index 4a6a182d0a88..22f0634dd3fa 100644
--- a/drivers/leds/trigger/ledtrig-cpu.c
+++ b/drivers/leds/trigger/ledtrig-cpu.c
@@ -92,13 +92,13 @@ static struct syscore_ops ledtrig_cpu_syscore_ops = {
.resume = ledtrig_cpu_syscore_resume,
};

-static int ledtrig_starting_cpu(unsigned int cpu)
+static int ledtrig_online_cpu(unsigned int cpu)
{
ledtrig_cpu(CPU_LED_START);
return 0;
}

-static int ledtrig_dying_cpu(unsigned int cpu)
+static int ledtrig_prepare_down_cpu(unsigned int cpu)
{
ledtrig_cpu(CPU_LED_STOP);
return 0;
@@ -107,6 +107,7 @@ static int ledtrig_dying_cpu(unsigned int cpu)
static int __init ledtrig_cpu_init(void)
{
int cpu;
+ int ret;

/* Supports up to 9999 cpu cores */
BUILD_BUG_ON(CONFIG_NR_CPUS > 9999);
@@ -126,12 +127,11 @@ static int __init ledtrig_cpu_init(void)

register_syscore_ops(&ledtrig_cpu_syscore_ops);

- /*
- * FIXME: Why needs this to happen in the interrupt disabled
- * low level bringup phase of a cpu?
- */
- cpuhp_setup_state(CPUHP_AP_LEDTRIG_STARTING, "AP_LEDTRIG_STARTING",
- ledtrig_starting_cpu, ledtrig_dying_cpu);
+ ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "AP_LEDTRIG_STARTING",
+ ledtrig_online_cpu, ledtrig_prepare_down_cpu);
+ if (ret < 0)
+ pr_err("CPU hotplug notifier for ledtrig-cpu could not be registered: %d\n",
+ ret);

pr_info("ledtrig-cpu: registered to indicate activity on CPUs\n");

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 09ef54bcba39..282800b42627 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -65,7 +65,6 @@ enum cpuhp_state {
CPUHP_AP_ARM_CORESIGHT_STARTING,
CPUHP_AP_ARM_CORESIGHT4_STARTING,
CPUHP_AP_ARM64_ISNDEP_STARTING,
- CPUHP_AP_LEDTRIG_STARTING,
CPUHP_AP_SMPCFD_DYING,
CPUHP_AP_X86_TBOOT_DYING,
CPUHP_AP_NOTIFY_STARTING,


Acked-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>

--
Best regards,
Jacek Anaszewski