From: sboyd@codeaurora•org (Stephen Boyd)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 01/18] led-triggers: create a trigger for CPU activity
Date: Thu, 19 Apr 2012 23:59:13 -0700 [thread overview]
Message-ID: <4F910941.4000702@codeaurora.org> (raw)
In-Reply-To: <1334660025-20442-2-git-send-email-bryan.wu@canonical.com>
On 4/17/2012 3:53 AM, Bryan Wu wrote:
> +static int __init ledtrig_cpu_init(void)
> +{
> + int cpu;
> +
> + /* Supports up to 9999 cpu cores */
> + BUILD_BUG_ON(CONFIG_NR_CPUS > 9999);
> +
> + /*
> + * Registering CPU led trigger for each CPU cores here
> + * ignores CPU hotplug, but after this CPU hotplug works
> + * fine with this trigger.
> + */
> + for_each_possible_cpu(cpu) {
> + struct led_trigger *trig;
> + char *name = per_cpu(trig_name, cpu);
> + struct rw_semaphore *lock = &per_cpu(trig_lock, cpu);
> +
> + init_rwsem(lock);
What is this lock protecting?
> +
> + snprintf(name, MAX_NAME_LEN, "cpu%d", cpu);
> +
> + down_write(lock);
> + led_trigger_register_simple(name, &trig);
> + per_cpu(cpu_trig, cpu) = trig;
> + up_write(lock);
This is the only place it is locked and unlocked.
I think the previous comment was about how led_trigger_register_simple()
exposed a live trigger but it wasn't assigned to the per_cpu variable
yet. Can we not just reorder the assignment so we have
struct led_trigger *trig = NULL;
...
per_cpu(cpu_trig, cpu) = trig;
led_trigger_register_simple();
?
--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
next prev parent reply other threads:[~2012-04-20 6:59 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-17 10:53 [PATCH v7 00/18] Introduce a led trigger for CPU activity and consolidate LED driver in ARM Bryan Wu
2012-04-17 10:53 ` [PATCH 01/18] led-triggers: create a trigger for CPU activity Bryan Wu
2012-04-17 22:52 ` Andrew Morton
2012-04-17 23:07 ` Richard Purdie
2012-04-30 5:14 ` Bryan Wu
2012-04-19 2:44 ` Bryan Wu
2012-04-20 6:59 ` Stephen Boyd [this message]
2012-04-20 7:26 ` Bryan Wu
2012-04-17 10:53 ` [PATCH 02/18] ARM: at91: convert old leds drivers to gpio_led and led_trigger drivers Bryan Wu
2012-04-17 10:53 ` [PATCH 03/18] ARM: mach-realview and mach-versatile: retire custom LED code Bryan Wu
2012-04-17 10:53 ` [PATCH 04/18] ARM: mach-ks8695: remove leds driver, since nobody use it Bryan Wu
2012-04-17 10:53 ` [PATCH 05/18] ARM: mach-shark: retire custom LED code Bryan Wu
2012-04-17 10:53 ` [PATCH 06/18] ARM: mach-orion5x: convert custom LED code to gpio_led and LED CPU trigger Bryan Wu
2012-04-17 10:53 ` [PATCH 07/18] ARM: mach-integrator: move CM_CTRL to header file for accessing by other functions Bryan Wu
2012-04-17 10:53 ` [PATCH 08/18] ARM: mach-integrator: retire custom LED code Bryan Wu
2012-04-17 10:53 ` [PATCH 09/18] ARM: mach-clps711x: retire custom LED code of P720T machine Bryan Wu
2012-04-17 10:53 ` [PATCH 10/18] ARM: mach-ebsa110: retire custom LED code Bryan Wu
2012-04-17 10:53 ` [PATCH 11/18] ARM: mach-footbridge: " Bryan Wu
2012-04-17 10:53 ` [PATCH 12/18] char: nwflash: remove old led event code Bryan Wu
2012-04-17 10:53 ` [PATCH 13/18] ARM: mach-pxa: retire custom LED code Bryan Wu
2012-04-17 10:53 ` [PATCH 14/18] ARM: plat-samsung: remove including old leds event API header file Bryan Wu
2012-04-17 10:53 ` [PATCH 15/18] ARM: mach-pnx4008: " Bryan Wu
2012-04-17 10:53 ` [PATCH 16/18] ARM: mach-omap1: retire custom LED code Bryan Wu
2012-04-17 10:53 ` [PATCH 17/18] ARM: mach-sa1100: " Bryan Wu
2012-04-17 10:53 ` [PATCH 18/18] ARM: use new LEDS CPU trigger stub to replace old one Bryan Wu
-- strict thread matches above, loose matches on Subject: below --
2012-08-13 5:51 [PATCH v10 00/18] Introduce a led trigger for CPU activity and consolidate LED driver in ARM Bryan Wu
2012-08-13 5:51 ` [PATCH 01/18] led-triggers: create a trigger for CPU activity Bryan Wu
2012-04-13 11:25 [PATCH v6 00/18] Introduce a led trigger for CPU activity and consolidate LED driver in ARM Bryan Wu
2012-04-13 11:26 ` [PATCH 01/18] led-triggers: create a trigger for CPU activity Bryan Wu
2012-04-13 14:56 ` Tim Gardner
2012-04-16 9:51 ` Bryan Wu
2012-04-16 18:09 ` Tim Gardner
2012-03-30 11:58 [PATCH v5 00/18] Introduce a led trigger for CPU activity and consolidate LED driver in ARM Bryan Wu
2012-03-30 11:58 ` [PATCH 01/18] led-triggers: create a trigger for CPU activity Bryan Wu
2012-04-06 22:15 ` Andrew Morton
2012-04-13 11:29 ` Bryan Wu
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