From patchwork Thu Aug 19 02:50:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ian Pilcher X-Patchwork-Id: 500723 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, 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 C49EEC432BE for ; Thu, 19 Aug 2021 02:51:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ADBD1610FB for ; Thu, 19 Aug 2021 02:51:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236124AbhHSCwG (ORCPT ); Wed, 18 Aug 2021 22:52:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51440 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236143AbhHSCvz (ORCPT ); Wed, 18 Aug 2021 22:51:55 -0400 Received: from mail-ot1-x329.google.com (mail-ot1-x329.google.com [IPv6:2607:f8b0:4864:20::329]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 24B69C06129E; Wed, 18 Aug 2021 19:51:13 -0700 (PDT) Received: by mail-ot1-x329.google.com with SMTP id r17-20020a0568302371b0290504f3f418fbso6795537oth.12; Wed, 18 Aug 2021 19:51:13 -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 :mime-version:content-transfer-encoding; bh=CHR8GEyHKCZ6Ukss9VRJCG5gxZXrolsRZXMVOL6995E=; b=a+E/hwq57irPKDH3Yx0253HMNP6ebrgBa3XT5+xMpZqo2G6bKFVh8HsaPRs3OqSaPE A5CY6TXhP/4ChaZuTbVk18v9B3XvC/kNBGp1/CWfQMpw4yGIQoX/QO/UifLarYqeRKTp FW8um0kWWK7/Jd2+fCIWvYNIY/5NbTzBwsvyYHHd2g66ey8phNLuC0D7QDKaSwkYa/ZU bDVaoic0k6lkTIqEomRQglTir16F9fzNpfBuCG7j3YpC0VSnPI4BEhd/qPRU+2FdpYnI qTvtDaTIlzWAKaYayzNsah7H716cWM8spf/8L3iSMEC4EtDvpCqvVnIcXIWi5keK3ZhN JL5A== 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:mime-version:content-transfer-encoding; bh=CHR8GEyHKCZ6Ukss9VRJCG5gxZXrolsRZXMVOL6995E=; b=XK7Y0av1dZAeB3xjcj+R/rqFmASuoTsSzStMqANAjmICBfOOEY9rXlxiUXOw2mb7Yz a3HfH2bMDuvFdb3n88D+q0Eosh1LUXs8ucC6KBWytb/QDyJY05AjBJVIKOMDGKxDgmyQ ZXmVntsf0h23xHp8AgHK6zMAsWZ4qFNlLc06DZc1Y+J4bpyrLMqeRmYdZ7pgO3p4Uu1+ 5vWnLFdYclFZfekNyRnPdZHitB9tMhzspEPJ3LCqSlLk7wtrizyHKUfRZ3WPwHxm9Q/2 n2cFJ32dkB+6l+fdNYIqPuhxfqsogwRtDqvySARZ3c4ABzDDY4wmPuDPyzvLNL42x5Bw +cBg== X-Gm-Message-State: AOAM531Cu6UN2TnGc4kefY+J21ArO4bXsflg9d2hR177YU52cQqm/BAa nni3CMhRePVJDHvnoNHB/ahfj2IF7XItjFsR X-Google-Smtp-Source: ABdhPJwYn0zhky0T0oFkOw81AF80BaiHQyx4j85uT/pQJYNmeMUXQeqiBjX8nbS0H3WwNh8cwZOD6w== X-Received: by 2002:a9d:3a6:: with SMTP id f35mr7709660otf.144.1629341472243; Wed, 18 Aug 2021 19:51:12 -0700 (PDT) Received: from ian.penurio.us ([47.184.51.90]) by smtp.gmail.com with ESMTPSA id w15sm156792oiw.19.2021.08.18.19.51.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Aug 2021 19:51:11 -0700 (PDT) From: Ian Pilcher To: linux-block@vger.kernel.org, linux-leds@vger.kernel.org Cc: axboe@kernel.dk, pavel@ucw.cz, kabel@kernel.org, linux-kernel@vger.kernel.org, kernelnewbies@kernelnewbies.org Subject: [RFC PATCH v3 11/18] ledtrig-blkdev: Add function to associate a device with an LED Date: Wed, 18 Aug 2021 21:50:46 -0500 Message-Id: <20210819025053.222710-12-arequipeno@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210819025053.222710-1-arequipeno@gmail.com> References: <20210819025053.222710-1-arequipeno@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-leds@vger.kernel.org If this is the first LED associated with the device, create the /sys/block//blkdev_leds directory. Otherwise, increment its reference count. Create symlinks in /sys/class/leds//block_devices and /sys/block//blkdev_leds If this the first device associated with any LED, schedule delayed work to periodically check associated devices and blink LEDs Signed-off-by: Ian Pilcher --- drivers/leds/trigger/ledtrig-blkdev.c | 168 ++++++++++++++++++++++++++ 1 file changed, 168 insertions(+) diff --git a/drivers/leds/trigger/ledtrig-blkdev.c b/drivers/leds/trigger/ledtrig-blkdev.c index 2072cc904616..a1646752b9a0 100644 --- a/drivers/leds/trigger/ledtrig-blkdev.c +++ b/drivers/leds/trigger/ledtrig-blkdev.c @@ -312,3 +312,171 @@ void ledtrig_blkdev_disk_cleanup(struct gendisk *const gd) mutex_unlock(&ledtrig_blkdev_mutex); } EXPORT_SYMBOL_GPL(ledtrig_blkdev_disk_cleanup); + + +/* + * + * Associate a block device with an LED + * + */ + +/* Gets or allocs & initializes the blkdev disk for a gendisk */ +static int blkdev_get_disk(struct gendisk *const gd) +{ + struct ledtrig_blkdev_disk *disk; + struct kobject *dir; + + if (gd->ledtrig != NULL) { + kobject_get(gd->ledtrig->dir); + return 0; + } + + disk = kmalloc(sizeof(*disk), GFP_KERNEL); + if (disk == NULL) + return -ENOMEM; + + dir = blkdev_mkdir("blkdev_leds", &disk_to_dev(gd)->kobj); + if (IS_ERR(dir)) { + kfree(disk); + return PTR_ERR(dir); + } + + INIT_HLIST_HEAD(&disk->leds); + disk->gd = gd; + disk->dir = dir; + disk->read_ios = 0; + disk->write_ios = 0; + + gd->ledtrig = disk; + + return 0; +} + +static void blkdev_put_disk(struct ledtrig_blkdev_disk *const disk) +{ + kobject_put(disk->dir); + + if (hlist_empty(&disk->leds)) { + disk->gd->ledtrig = NULL; + kfree(disk); + } +} + +static int blkdev_disk_add_locked(struct ledtrig_blkdev_led *const led, + struct gendisk *const gd) +{ + struct ledtrig_blkdev_link *link; + struct ledtrig_blkdev_disk *disk; + unsigned long delay; + int ret; + + link = kmalloc(sizeof(*link), GFP_KERNEL); + if (link == NULL) { + ret = -ENOMEM; + goto error_return; + } + + ret = blkdev_get_disk(gd); + if (ret != 0) + goto error_free_link; + + disk = gd->ledtrig; + + ret = sysfs_create_link(disk->dir, &led->led_dev->dev->kobj, + led->led_dev->name); + if (ret != 0) + goto error_put_disk; + + ret = sysfs_create_link(led->dir, &disk_to_dev(gd)->kobj, + gd->disk_name); + if (ret != 0) + goto error_remove_link; + + link->disk = disk; + link->led = led; + hlist_add_head(&link->led_disks_node, &led->disks); + hlist_add_head(&link->disk_leds_node, &disk->leds); + + if (ledtrig_blkdev_count == 0) { + delay = READ_ONCE(ledtrig_blkdev_interval); + WARN_ON(!schedule_delayed_work(&ledtrig_blkdev_work, delay)); + } + + ++ledtrig_blkdev_count; + + return 0; + +error_remove_link: + sysfs_remove_link(disk->dir, led->led_dev->name); +error_put_disk: + blkdev_put_disk(disk); +error_free_link: + kfree(link); +error_return: + return ret; +} + +static bool blkdev_already_linked(const struct ledtrig_blkdev_led *const led, + const struct gendisk *const gd) +{ + const struct ledtrig_blkdev_link *link; + + if (gd->ledtrig == NULL) + return false; + + hlist_for_each_entry(link, &gd->ledtrig->leds, disk_leds_node) { + + if (link->led == led) { + pr_info("blkdev LED: %s already associated with %s\n", + gd->disk_name, led->led_dev->name); + return true; + } + } + + return false; +} + +static int blkdev_disk_add(struct ledtrig_blkdev_led *const led, + const char *const disk_name, const size_t name_len) +{ + static char name[DISK_NAME_LEN]; /* only used w/ mutex locked */ + struct gendisk *gd; + int ret; + + if (name_len >= DISK_NAME_LEN) { + pr_info("blkdev LED: invalid device name %.*s\n", + (int)name_len, disk_name); + ret = -EINVAL; + goto exit_return; + } + + ret = mutex_lock_interruptible(&ledtrig_blkdev_mutex); + if (ret != 0) + goto exit_return; + + memcpy(name, disk_name, name_len); + name[name_len] = 0; + gd = get_disk_by_name(name); /* increments disk's refcount */ + + if (gd == NULL) { + pr_info("blkdev LED: no such block device %.*s\n", + (int)name_len, disk_name); + ret = -ENODEV; + goto exit_unlock; + } + + if (blkdev_already_linked(led, gd)) { + ret = -EEXIST; + goto exit_put_dev; + } + + ret = blkdev_disk_add_locked(led, gd); + +exit_put_dev: + if (ret != 0) + put_device(disk_to_dev(gd)); +exit_unlock: + mutex_unlock(&ledtrig_blkdev_mutex); +exit_return: + return ret; +}