From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CCB31C4CEC6 for ; Thu, 12 Sep 2019 14:40:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9B2B9206A5 for ; Thu, 12 Sep 2019 14:40:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="SbJm17Uk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732727AbfILOkV (ORCPT ); Thu, 12 Sep 2019 10:40:21 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:36635 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732592AbfILOkU (ORCPT ); Thu, 12 Sep 2019 10:40:20 -0400 Received: by mail-pf1-f196.google.com with SMTP id y22so16171647pfr.3; Thu, 12 Sep 2019 07:40:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=9AgdMynI1ZAA7JeCF/sT/EVViwMRnFrt1eKXKnGAHwk=; b=SbJm17Uk9xDJ8+HUu1bt3jYYPPs+1souh/nhp2HtTf8drQ41Pw8MQdkb9ltSQifAv0 AOa0W8+VmtNmns7NwCkE04Kq2JVi5YVUbrW3k0qNpRWamqUhJ9ELNDRiGdEc4Y/IxqEo zDOgdw/ZhF+nTzj+z5fN39L9t4BgUlMqDo5r/J+DBoRwOu8hglAbuvfEXn/fXH2u47+7 FcV0LLHSnfzawH9wKB2uS+1HYgf8Eoc7lMYsA+YHUHSCM/vf5df8/tcNdqyiynRF7mwM KPIw8zw3KSHBNsEKTpLNLbM/1Xn232n5Y7PruUi5yk7mv8DbUakKcqvJRfepRVFfbLYS LWbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=9AgdMynI1ZAA7JeCF/sT/EVViwMRnFrt1eKXKnGAHwk=; b=KRrSZhvXulrx7hwAx/BK+Rsk661jRqmBylnBlUMWDiuWgzIIQOYWXBnRIphla5BKtB 1gPesTREKqO/MOTuHu3vADSC2+4vrrm0/wIKx26ol69RatRgs2TyxQ5KOZdcGn9ZEOQD 5INmp/ls/6NdFQLKDnBK8fEtRK/ZPtmU/XEF4mnqHrDrl/kII1NLZ2VzGXLKnkQrUq8W OpPQQjbhq9OiTB54FI251wqZVFH3SkRpeCQ8O8BrjMRiPAlk51c8ciIUq3N/UtSC4q41 CMeSx6GCrWtwD2we0FflcnHvbuHdUQbuVxHA8/C7mwyKAXaPU+2MGqARZi0TsyWKjAVP htUw== X-Gm-Message-State: APjAAAX9xgmNOlk4X8QRsHSSd2qXks8u/9MKQknBa6N0BL7+vDzvZ+6z rLxnjnEpSDgjrTYqaIKecIAlBWnK X-Google-Smtp-Source: APXvYqx8ytoFqcf8SFiVf1zxmEx1E1wgooqSfRsNpLSZN0qyOok9P0qmJ1M1U2Lw+ssAy2160Qgjvw== X-Received: by 2002:aa7:980c:: with SMTP id e12mr47789354pfl.79.1568299219838; Thu, 12 Sep 2019 07:40:19 -0700 (PDT) Received: from localhost.localdomain ([240f:34:212d:1:a9d6:f377:69:9ad0]) by smtp.gmail.com with ESMTPSA id b3sm42125514pfp.65.2019.09.12.07.40.15 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 12 Sep 2019 07:40:18 -0700 (PDT) From: Akinobu Mita To: linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Akinobu Mita , Greg Kroah-Hartman , "Rafael J. Wysocki" , Jacek Anaszewski , Pavel Machek , Dan Murphy Subject: [PATCH] leds: remove PAGE_SIZE limit of /sys/class/leds//trigger Date: Thu, 12 Sep 2019 23:39:49 +0900 Message-Id: <1568299189-11074-2-git-send-email-akinobu.mita@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1568299189-11074-1-git-send-email-akinobu.mita@gmail.com> References: <1568299189-11074-1-git-send-email-akinobu.mita@gmail.com> Sender: linux-leds-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-leds@vger.kernel.org Reading /sys/class/leds//trigger returns all available LED triggers. However, the size of this file is limited to PAGE_SIZE because of the limitation for sysfs attribute. Enabling LED CPU trigger on systems with thousands of CPUs easily hits PAGE_SIZE limit, and makes it impossible to see all available LED triggers and which trigger is currently activated. We work around it here by converting /sys/class/leds//trigger to binary attribute, which is not limited by length. This is _not_ good design, do not copy it. Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Jacek Anaszewski Cc: Pavel Machek Cc: Dan Murphy Acked-by: Pavel Machek Signed-off-by: Akinobu Mita --- drivers/leds/led-class.c | 8 ++-- drivers/leds/led-triggers.c | 90 ++++++++++++++++++++++++++++++++++----------- drivers/leds/leds.h | 6 +++ include/linux/leds.h | 5 --- 4 files changed, 79 insertions(+), 30 deletions(-) diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index 4793e77..8b5a1d1 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -73,13 +73,13 @@ static ssize_t max_brightness_show(struct device *dev, static DEVICE_ATTR_RO(max_brightness); #ifdef CONFIG_LEDS_TRIGGERS -static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store); -static struct attribute *led_trigger_attrs[] = { - &dev_attr_trigger.attr, +static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0); +static struct bin_attribute *led_trigger_bin_attrs[] = { + &bin_attr_trigger, NULL, }; static const struct attribute_group led_trigger_group = { - .attrs = led_trigger_attrs, + .bin_attrs = led_trigger_bin_attrs, }; #endif diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c index 8d11a5e..ed5a311 100644 --- a/drivers/leds/led-triggers.c +++ b/drivers/leds/led-triggers.c @@ -16,6 +16,7 @@ #include #include #include +#include #include "leds.h" /* @@ -26,9 +27,11 @@ LIST_HEAD(trigger_list); /* Used by LED Class */ -ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr, - const char *buf, size_t count) +ssize_t led_trigger_write(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, char *buf, + loff_t pos, size_t count) { + struct device *dev = kobj_to_dev(kobj); struct led_classdev *led_cdev = dev_get_drvdata(dev); struct led_trigger *trig; int ret = count; @@ -64,39 +67,84 @@ ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr, mutex_unlock(&led_cdev->led_access); return ret; } -EXPORT_SYMBOL_GPL(led_trigger_store); +EXPORT_SYMBOL_GPL(led_trigger_write); -ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr, - char *buf) +__printf(4, 5) +static int led_trigger_snprintf(char *buf, size_t size, bool query, + const char *fmt, ...) +{ + va_list args; + int i; + + va_start(args, fmt); + if (query) + i = vsnprintf(NULL, 0, fmt, args); + else + i = vscnprintf(buf, size, fmt, args); + va_end(args); + + return i; +} + +static int led_trigger_format(char *buf, size_t size, bool query, + struct led_classdev *led_cdev) { - struct led_classdev *led_cdev = dev_get_drvdata(dev); struct led_trigger *trig; - int len = 0; + int len = led_trigger_snprintf(buf, size, query, "%s", + led_cdev->trigger ? "none" : "[none]"); + + list_for_each_entry(trig, &trigger_list, next_trig) { + bool hit = led_cdev->trigger && + !strcmp(led_cdev->trigger->name, trig->name); + + len += led_trigger_snprintf(buf + len, size - len, query, + " %s%s%s", hit ? "[" : "", + trig->name, hit ? "]" : ""); + } + + len += led_trigger_snprintf(buf + len, size - len, query, "\n"); + + return len; +} + +/* + * It was stupid to create 10000 cpu triggers, but we are stuck with it now. + * Don't make that mistake again. We work around it here by creating binary + * attribute, which is not limited by length. This is _not_ good design, do not + * copy it. + */ +ssize_t led_trigger_read(struct file *filp, struct kobject *kobj, + struct bin_attribute *attr, char *buf, + loff_t pos, size_t count) +{ + struct device *dev = kobj_to_dev(kobj); + struct led_classdev *led_cdev = dev_get_drvdata(dev); + void *data; + int len; down_read(&triggers_list_lock); down_read(&led_cdev->trigger_lock); - if (!led_cdev->trigger) - len += scnprintf(buf+len, PAGE_SIZE - len, "[none] "); + len = led_trigger_format(NULL, 0, true, led_cdev); + data = kvmalloc(len + 1, GFP_KERNEL); + if (data) + len = led_trigger_format(data, len + 1, false, led_cdev); else - len += scnprintf(buf+len, PAGE_SIZE - len, "none "); + len = -ENOMEM; - list_for_each_entry(trig, &trigger_list, next_trig) { - if (led_cdev->trigger && !strcmp(led_cdev->trigger->name, - trig->name)) - len += scnprintf(buf+len, PAGE_SIZE - len, "[%s] ", - trig->name); - else - len += scnprintf(buf+len, PAGE_SIZE - len, "%s ", - trig->name); - } up_read(&led_cdev->trigger_lock); up_read(&triggers_list_lock); - len += scnprintf(len+buf, PAGE_SIZE - len, "\n"); + if (len < 0) + return len; + + len = memory_read_from_buffer(buf, count, &pos, data, len); + + kvfree(data); + return len; } -EXPORT_SYMBOL_GPL(led_trigger_show); +EXPORT_SYMBOL_GPL(led_trigger_read); /* Caller must ensure led_cdev->trigger_lock held */ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig) diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h index 47b2294..a0ee33c 100644 --- a/drivers/leds/leds.h +++ b/drivers/leds/leds.h @@ -23,6 +23,12 @@ void led_set_brightness_nopm(struct led_classdev *led_cdev, enum led_brightness value); void led_set_brightness_nosleep(struct led_classdev *led_cdev, enum led_brightness value); +ssize_t led_trigger_read(struct file *filp, struct kobject *kobj, + struct bin_attribute *attr, char *buf, + loff_t pos, size_t count); +ssize_t led_trigger_write(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, char *buf, + loff_t pos, size_t count); extern struct rw_semaphore leds_list_lock; extern struct list_head leds_list; diff --git a/include/linux/leds.h b/include/linux/leds.h index fd2eb7c..33ae825 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -290,11 +290,6 @@ struct led_trigger { #define led_trigger_get_led(dev) ((struct led_classdev *)dev_get_drvdata((dev))) #define led_trigger_get_drvdata(dev) (led_get_trigger_data(led_trigger_get_led(dev))) -ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr, - const char *buf, size_t count); -ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr, - char *buf); - /* Registration functions for complex triggers */ extern int led_trigger_register(struct led_trigger *trigger); extern void led_trigger_unregister(struct led_trigger *trigger); -- 2.7.4