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[83.31.81.20]) by smtp.gmail.com with ESMTPSA id 12sm9549238wmi.34.2019.09.01.09.53.35 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 01 Sep 2019 09:53:36 -0700 (PDT) Subject: Re: [PATCH] leds: remove PAGE_SIZE limit of /sys/class/leds//trigger To: Akinobu Mita , linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Pavel Machek , Dan Murphy , Greg KH References: <1567090164-6819-1-git-send-email-akinobu.mita@gmail.com> From: Jacek Anaszewski Openpgp: preference=signencrypt Autocrypt: addr=jacek.anaszewski@gmail.com; prefer-encrypt=mutual; keydata= mQINBFWjfaEBEADd66EQbd6yd8YjG0kbEDT2QIkx8C7BqMXR8AdmA1OMApbfSvEZFT1D/ECR eWFBS8XtApKQx1xAs1j5z70k3zebk2eeNs5ahxi6vM4Qh89vBM46biSKeeX5fLcv7asmGb/a FnHPAfQaKFyG/Bj9V+//ef67hpjJWR3s74C6LZCFLcbZM0z/wTH+baA5Jwcnqr4h/ygosvhP X3gkRzJLSFYekmEv+WHieeKXLrJdsUPUvPJTZtvi3ELUxHNOZwX2oRJStWpmL2QGMwPokRNQ 29GvnueQdQrIl2ylhul6TSrClMrKZqOajDFng7TLgvNfyVZE8WQwmrkTrdzBLfu3kScjE14Q Volq8OtQpTsw5570D4plVKh2ahlhrwXdneSot0STk9Dh1grEB/Jfw8dknvqkdjALUrrM45eF FM4FSMxIlNV8WxueHDss9vXRbCUxzGw37Ck9JWYo0EpcpcvwPf33yntYCbnt+RQRjv7vy3w5 osVwRR4hpbL/fWt1AnZ+RvbP4kYSptOCPQ+Pp1tCw16BOaPjtlqSTcrlD2fo2IbaB5D21SUa IsdZ/XkD+V2S9jCrN1yyK2iKgxtDoUkWiqlfRgH2Ep1tZtb4NLF/S0oCr7rNLO7WbqLZQh1q ShfZR16h7YW//1/NFwnyCVaG1CP/L/io719dPWgEd/sVSKT2TwARAQABtC1KYWNlayBBbmFz emV3c2tpIDxqYWNlay5hbmFzemV3c2tpQGdtYWlsLmNvbT6JAlgEEwEIAEICGwMHCwkIBwMC AQYVCAIJCgsDFgIBAh4BAheABQkJZgNMFiEEvx38ClaPBfeVdXCQvWpQHLeLfCYFAl05/9sC GQEACgkQvWpQHLeLfCarMQ/9FN/WqJdN2tf6xkP0RFyS4ft0sT04zkOCFfOMxs8mZ+KZoMU+ X3a+fEppDL7xgRFpHyGaEel7lSi1eqtzsqZ5JiHbDS1Ht1G8TtATb8q8id68qeSeW2mfzaLQ 98NPELGfUXFoUqUQkG5z2p92UrGF4Muj1vOIW93pwvE4uDpNsl+jriwHomLtjIUoZtIRjGfZ RCyUQI0vi5LYzXCebuzAjGD7Jh2YAp7fDGrv3qTq8sX+DUJ4H/+I8PiL+jXKkEeppqIhlBJJ l4WcgggMu3c2uljYDuqRYghte33BXyCPAocfO2/sN+yJRUTVuRFlOxUk4srz/W8SQDwOAwtK V7TzdyF1/jOGBxWwS13EjMb4u3XwPMzcPlEQNdIqz76NFmJ99xYEvgkAmFmRioxuBTRv8Fs1 c1jQ00WWJ5vezqY6lccdDroPalXWeFzfPjIhKbV3LAYTlqv0It75GW9+0TBhPqdTM15DrCVX B7Ues7UnD5FBtWwewTnwr+cu8te449VDMzN2I+a9YKJ1s6uZmzh5HnuKn6tAfGyQh8MujSOM lZrNHrRsIsLXOjeGVa84Qk/watEcOoyQ7d+YaVosU0OCZl0GldvbGp1z2u8cd2N/HJ7dAgFh Q7dtGXmdXpt2WKQvTvQXhIrCWVQErNYbDZDD2V0TZtlPBaZP4fkUDkvH+Sy5Ag0EVaN9oQEQ AMPNymBNoCWc13U6qOztXrIKBVsLGZXq/yOaR2n7gFbFACD0TU7XuH2UcnwvNR+uQFwSrRqa EczX2V6iIy2CITXKg5Yvg12yn09gTmafuoIyKoU16XvC3aZQQ2Bn3LO2sRP0j/NuMD9GlO37 pHCVRpI2DPxFE39TMm1PLbHnDG8+lZql+dpNwWw8dDaRgyXx2Le542CcTBT52VCeeWDtqd2M wOr4LioYlfGfAqmwcwucBdTEBUxklQaOR3VbJQx6ntI2oDOBlNGvjnVDzZe+iREd5l40l+Oj TaiWvBGXkv6OI+wx5TFPp+BM6ATU+6UzFRTUWbj+LqVA/JMqYHQp04Y4H5GtjbHCa8abRvBw IKEvpwTyWZlfXPtp8gRlNmxYn6gQlTyEZAWodXwE7CE+KxNnq7bPHeLvrSn8bLNK682PoTGr 0Y00bguYLfyvEwuDYek1/h9YSXtHaCR3CEj4LU1B561G1j7FVaeYbX9bKBAoy/GxAW8J5O1n mmw7FnkSHuwO/QDe0COoO0QZ620Cf9IBWYHW4m2M2yh5981lUaiMcNM2kPgsJFYloFo2XGn6 lWU9BrWjEoNDhHZtF+yaPEuwjZo6x/3E2Tu3E5Jj0VpVcE9U1Zq/fquDY79l2RJn5ENogOs5 +Pi0GjVpEYQVWfm0PTCxNPOzOzGR4QB3BNFvABEBAAGJAiUEGAEIAA8FAlWjfaECGwwFCQlm AYAACgkQvWpQHLeLfCZqGxAAlWBWVvjU6xj70GwengiqYZwmW1i8gfS4TNibQT/KRq0zkBnE wgKwXRbVoW38pYVuGa5x/JDQMJDrLAJ0wrCOS3XxbSHCWOl/k2ZD9OaxUeXq6N+OmGTzfrYv PUvWS1Hy04q9AD1dIaMNruZQmvnRfkOk2UDncDIg0166/NTHiYI09H5mpWGpHn/2aT6dmpVw uoM9/rHlF5s5qAAo95tZ0QW2BtIceG9/rbYlL57waSMPF49awvwLQX5RhWoF8mPS5LsBrXXK hmizIsn40tLbi2RtWjzDWgZYitqmmqijeCnDvISN4qJ/nCLO4DjiSGs59w5HR+l0nwePDhOC A4RYZqS1e2Clx1VSkDXFpL3egabcIsqK7CZ6a21r8lXVpo4RnMlQsmXZTnRx4SajFvX7PrRg /02C811fLfh2r5O5if8sKQ6BKKlHpuuioqfj/w9z3B0aQ71e4n1zNJBO1kcdznikPLAbr7jG gkBUXT1yJiwpTfRQr5y2Uo12IJsKxohnNFVYtK8X/R6S0deKPjrZWvAkllgIPcHjMi2Va8yw KTj/JgcpUO5KN906Pf7ywZISe7Kbcc/qnE0YjPPSqFOvoeZvHe6EZCMW9+xZsaipvlqpByQV UHnVg09K9YFvjUBsBPdC8ef6YwgfR9o6AnPmxl0oMUIXkCCC5c99fzJY/k+JAq0EGAEIACAW IQS/HfwKVo8F95V1cJC9alAct4t8JgUCWwqKhgIbAgCBCRC9alAct4t8JnYgBBkWCAAdFiEE FMMcSshOZf56bfAEYhBsURv0pdsFAlsKioYACgkQYhBsURv0pdvELgD/U+y3/hsz0bIjMQJY 0LLxM/rFY9Vz1L43+lQHXjL3MPsA/1lNm5sailsY7aFBVJxAzTa8ZAGWBdVaGo6KCvimDB8G 7joP/jx+oGOmdRogs7mG//H+w9DTnBfPpnfkeiiokGYo/+huWO5V0Ac9tTqZeFc//t/YuYJn wWvS0Rx+KL0fT3eh9BQo47uF4yDiZIiWLNh4Agpup1MUSVsz4MjD0lW6ghtnLcGlIgoVHW0v tPW1m9jATYyJSOG/MC1iDrcYcp9uVYn5tKfkEeQNspuG6iSfS0q3tajPKnT1nJxMTxVOD2RW EIGfaV9Scrou92VD/eC+/8INRsiWS93j3hOKIAV5XRNINFqtzkagPYAP8r6wksjSjh01fSTB p5zxjfsIwWDDzDrqgzwv83CvrLXRV3OlG1DNUDYA52qJr47paH5QMWmHW5TNuoBX8qb6RW/H M3DzPgT+l+r1pPjMPfvL1t7civZUoPuNzoyFpQRj6TvWi2bGGMQKryeYksXG2zi2+avMFnLe lOxGdUZ7jn1SJ6Abba5WL3VrXCP+TUE6bZLgfw8kYa8QSXP3ysyeMI0topHFntBZ8a0KXBNs qqFCBWmTHXfwsfW0VgBmRtPO7eXVBybjJ1VXKR2RZxwSq/GoNXh/yrRXQxbcpZ+QP3/Tttsb FdKciZ4u3ts+5UwYra0BRuvb51RiZR2wRNnUeBnXWagJVTlG7RHBO/2jJOE6wrcdCMjs0Iiw PNWmiVoZA930TvHA5UeGENxdGqo2MvMdRJ54YaIR Message-ID: <6ebeedab-4a7f-14ea-d62e-9184e911047f@gmail.com> Date: Sun, 1 Sep 2019 18:53:34 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <1567090164-6819-1-git-send-email-akinobu.mita@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-leds-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-leds@vger.kernel.org Hi Akinobu, Thank you for the patch. I have one nit below but in general it looks good to me. I've tested it with 2000 mtd triggers (~14kB file size) and it worked flawlessly. Still, I would like to have ack from Greg for it. Adding Greg on Cc. On 8/29/19 4:49 PM, Akinobu Mita wrote: > 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. > > This converts /sys/class/leds//trigger to bin attribute and removes > the PAGE_SIZE limitation. > > Cc: Jacek Anaszewski > Cc: Pavel Machek > Cc: Dan Murphy > Signed-off-by: Akinobu Mita > --- > drivers/leds/led-class.c | 8 ++--- > drivers/leds/led-triggers.c | 84 ++++++++++++++++++++++++++++++++++----------- > drivers/leds/leds.h | 6 ++++ > include/linux/leds.h | 5 --- > 4 files changed, 74 insertions(+), 29 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..4788e00 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 +67,80 @@ 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; > > + len += led_trigger_snprintf(buf + len, size - len, query, "%s", Here we know len is 0 so we can pass just buf and size. > + 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; > +} > + > +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); > -- Best regards, Jacek Anaszewski