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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 86359C433E0 for ; Sun, 10 Jan 2021 17:55:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5FA1722AAA for ; Sun, 10 Jan 2021 17:55:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726769AbhAJRyx (ORCPT ); Sun, 10 Jan 2021 12:54:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726495AbhAJRyw (ORCPT ); Sun, 10 Jan 2021 12:54:52 -0500 Received: from mail-qt1-x849.google.com (mail-qt1-x849.google.com [IPv6:2607:f8b0:4864:20::849]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 801A2C061794 for ; Sun, 10 Jan 2021 09:54:12 -0800 (PST) Received: by mail-qt1-x849.google.com with SMTP id p20so11760289qtq.3 for ; Sun, 10 Jan 2021 09:54:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:message-id:mime-version:subject:from:to:cc; bh=PMmvRaQ36fTjEgj6kVCX++Tln5tlagkABbPEgCbdZho=; b=cJsZKMaB3JE5+MUy0LLtyp7E/B0xRpdgO1gMH+09nzW6KLmnjz+a+TzXB1D+eMJHJe k5+pmAs8RQXMZXqr3wvSI98Cg97ua5OjRHWp5jQ7io1yhha42XGV5f5eq4eDSvLT4voh uGbOMwTz4kGj/4zfEsv3XbvmaY/gULHWe2vZzVM9WfbGiuMiNI2WkdUFKUfPHwhWgf75 0RQlkUzyhr0UrdFJY/Db3sA64xrWooDXuW7OMdVRDoS6PfuQ8BiUS+yeAdKhSiE5fs9V MJsF8Gj4AgYR6D/4PbjYoVbNuIfWD4x62+398Uh4URilIe4aPWLEPrHqwNtCFhx2ZIcy tIwA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:message-id:mime-version:subject:from :to:cc; bh=PMmvRaQ36fTjEgj6kVCX++Tln5tlagkABbPEgCbdZho=; b=ZieU0+ckubgWJNIEjPrUtUWx9WwjsRKc3JWGWS0bUZMUlIrlmWQyIsRAHVa1AQa34Z EeOTnE2/LeZ8Fmm8NlyJPk+H+S4qwNxVltEdqU94Pxczi34Hl2wp7DIxiXLyxkhK7j6k JLgvh0WQlArZ2HuuSAfU5PaP+Gz/FPL774J/RbjG81Sl2uxZM+jbVj7XShz1XGJbbLBu NP8gPGt4djwEsmbgfV0xJQvLfCOEdbYpeGpnY9jVoPwcB2dxsh9hyM5rxv0sr0htdvPa mD3w3Thp+oIFEKDKF+aEoEEhmnWOQBCo/3ogAiIZcMZNX2OwgsT4RJuwGvCj+mvuXp6K +9TA== X-Gm-Message-State: AOAM531VyGAbB1ewpAiarIkLMuarJ0s6GajuqPSK+/nCj1LBIC0Ch82N HiYc5Q0QZfn7KWh5h7bL/Dc1cYPsIFFe6vo= X-Google-Smtp-Source: ABdhPJxxFxEdB7Ve+ZXR4qEY23p/VHRY1z0BnWOv1bfqqOQkaaJYI3FMOfKYAElPSQl2BD0CJTyX3bDHWiyrCp8= Sender: "saravanak via sendgmr" X-Received: from saravanak.san.corp.google.com ([2620:15c:2d:3:7220:84ff:fe09:fedc]) (user=saravanak job=sendgmr) by 2002:a0c:f812:: with SMTP id r18mr12545001qvn.39.1610301251482; Sun, 10 Jan 2021 09:54:11 -0800 (PST) Date: Sun, 10 Jan 2021 09:54:07 -0800 Message-Id: <20210110175408.1465657-1-saravanak@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.30.0.284.gd98b1dd5eaa7-goog Subject: [PATCH v4] driver core: Fix device link device name collision From: Saravana Kannan To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Saravana Kannan Cc: stable@vger.kernel.org, Michael Walle , kernel-team@android.com, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The device link device's name was of the form: -- This can cause name collision as reported here [1] as device names are not globally unique. Since device names have to be unique within the bus/class, add the bus/class name as a prefix to the device names used to construct the device link device name. So the devuce link device's name will be of the form: :--: [1] - https://lore.kernel.org/lkml/20201229033440.32142-1-michael@walle.cc/ Cc: stable@vger.kernel.org Fixes: 287905e68dd2 ("driver core: Expose device link details in sysfs") Reported-by: Michael Walle Tested-by: Michael Walle Signed-off-by: Saravana Kannan --- v1: - Fixed the collision in the device link device name. v1 -> v2: - Tried to fixed collision in the supplier: and consumer: symlinks v2 -> v3: - Fixed the truncation of the symlink names caused by v2. v3 -> v4: - Did all the above fixes for the symlink removal path. Documentation/ABI/testing/sysfs-class-devlink | 4 +-- .../ABI/testing/sysfs-devices-consumer | 5 ++-- .../ABI/testing/sysfs-devices-supplier | 5 ++-- drivers/base/core.c | 27 ++++++++++--------- include/linux/device.h | 12 +++++++++ 5 files changed, 35 insertions(+), 18 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-class-devlink b/Documentation/ABI/testing/sysfs-class-devlink index b662f747c83e..8a21ce515f61 100644 --- a/Documentation/ABI/testing/sysfs-class-devlink +++ b/Documentation/ABI/testing/sysfs-class-devlink @@ -5,8 +5,8 @@ Description: Provide a place in sysfs for the device link objects in the kernel at any given time. The name of a device link directory, denoted as ... above, is of the form -- - where is the supplier device name and is - the consumer device name. + where is the supplier bus:device name and + is the consumer bus:device name. What: /sys/class/devlink/.../auto_remove_on Date: May 2020 diff --git a/Documentation/ABI/testing/sysfs-devices-consumer b/Documentation/ABI/testing/sysfs-devices-consumer index 1f06d74d1c3c..0809fda092e6 100644 --- a/Documentation/ABI/testing/sysfs-devices-consumer +++ b/Documentation/ABI/testing/sysfs-devices-consumer @@ -4,5 +4,6 @@ Contact: Saravana Kannan Description: The /sys/devices/.../consumer: are symlinks to device links where this device is the supplier. denotes the - name of the consumer in that device link. There can be zero or - more of these symlinks for a given device. + name of the consumer in that device link and is of the form + bus:device name. There can be zero or more of these symlinks + for a given device. diff --git a/Documentation/ABI/testing/sysfs-devices-supplier b/Documentation/ABI/testing/sysfs-devices-supplier index a919e0db5e90..207f5972e98d 100644 --- a/Documentation/ABI/testing/sysfs-devices-supplier +++ b/Documentation/ABI/testing/sysfs-devices-supplier @@ -4,5 +4,6 @@ Contact: Saravana Kannan Description: The /sys/devices/.../supplier: are symlinks to device links where this device is the consumer. denotes the - name of the supplier in that device link. There can be zero or - more of these symlinks for a given device. + name of the supplier in that device link and is of the form + bus:device name. There can be zero or more of these symlinks + for a given device. diff --git a/drivers/base/core.c b/drivers/base/core.c index 25e08e5f40bd..47a6faf1605a 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -456,7 +456,9 @@ static int devlink_add_symlinks(struct device *dev, struct device *con = link->consumer; char *buf; - len = max(strlen(dev_name(sup)), strlen(dev_name(con))); + len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)), + strlen(dev_bus_name(con)) + strlen(dev_name(con))); + len += strlen(":"); len += strlen("supplier:") + 1; buf = kzalloc(len, GFP_KERNEL); if (!buf) @@ -470,12 +472,12 @@ static int devlink_add_symlinks(struct device *dev, if (ret) goto err_con; - snprintf(buf, len, "consumer:%s", dev_name(con)); + snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con)); ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf); if (ret) goto err_con_dev; - snprintf(buf, len, "supplier:%s", dev_name(sup)); + snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup)); ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf); if (ret) goto err_sup_dev; @@ -483,7 +485,7 @@ static int devlink_add_symlinks(struct device *dev, goto out; err_sup_dev: - snprintf(buf, len, "consumer:%s", dev_name(con)); + snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con)); sysfs_remove_link(&sup->kobj, buf); err_con_dev: sysfs_remove_link(&link->link_dev.kobj, "consumer"); @@ -506,7 +508,9 @@ static void devlink_remove_symlinks(struct device *dev, sysfs_remove_link(&link->link_dev.kobj, "consumer"); sysfs_remove_link(&link->link_dev.kobj, "supplier"); - len = max(strlen(dev_name(sup)), strlen(dev_name(con))); + len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)), + strlen(dev_bus_name(con)) + strlen(dev_name(con))); + len += strlen(":"); len += strlen("supplier:") + 1; buf = kzalloc(len, GFP_KERNEL); if (!buf) { @@ -514,9 +518,9 @@ static void devlink_remove_symlinks(struct device *dev, return; } - snprintf(buf, len, "supplier:%s", dev_name(sup)); + snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup)); sysfs_remove_link(&con->kobj, buf); - snprintf(buf, len, "consumer:%s", dev_name(con)); + snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con)); sysfs_remove_link(&sup->kobj, buf); kfree(buf); } @@ -737,8 +741,9 @@ struct device_link *device_link_add(struct device *consumer, link->link_dev.class = &devlink_class; device_set_pm_not_required(&link->link_dev); - dev_set_name(&link->link_dev, "%s--%s", - dev_name(supplier), dev_name(consumer)); + dev_set_name(&link->link_dev, "%s:%s--%s:%s", + dev_bus_name(supplier), dev_name(supplier), + dev_bus_name(consumer), dev_name(consumer)); if (device_register(&link->link_dev)) { put_device(consumer); put_device(supplier); @@ -1808,9 +1813,7 @@ const char *dev_driver_string(const struct device *dev) * never change once they are set, so they don't need special care. */ drv = READ_ONCE(dev->driver); - return drv ? drv->name : - (dev->bus ? dev->bus->name : - (dev->class ? dev->class->name : "")); + return drv ? drv->name : dev_bus_name(dev); } EXPORT_SYMBOL(dev_driver_string); diff --git a/include/linux/device.h b/include/linux/device.h index 89bb8b84173e..1779f90eeb4c 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -609,6 +609,18 @@ static inline const char *dev_name(const struct device *dev) return kobject_name(&dev->kobj); } +/** + * dev_bus_name - Return a device's bus/class name, if at all possible + * @dev: struct device to get the bus/class name of + * + * Will return the name of the bus/class the device is attached to. If it is + * not attached to a bus/class, an empty string will be returned. + */ +static inline const char *dev_bus_name(const struct device *dev) +{ + return dev->bus ? dev->bus->name : (dev->class ? dev->class->name : ""); +} + __printf(2, 3) int dev_set_name(struct device *dev, const char *name, ...); #ifdef CONFIG_NUMA -- 2.30.0.284.gd98b1dd5eaa7-goog