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[2620:137:e000::1:20]) by mx.google.com with ESMTP id d2-20020a17090a110200b0022be3049e52si437533pja.34.2023.03.13.12.12.08; Mon, 13 Mar 2023 12:12:23 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=T8oFJt9D; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231477AbjCMSdA (ORCPT + 99 others); Mon, 13 Mar 2023 14:33:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231355AbjCMScW (ORCPT ); Mon, 13 Mar 2023 14:32:22 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A1711CAD1 for ; Mon, 13 Mar 2023 11:31:21 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B3512B811EA for ; Mon, 13 Mar 2023 18:31:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0FC1FC433EF; Mon, 13 Mar 2023 18:30:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678732259; bh=hPDqRd7gJAlE6q+8Dn7WGhvvs2+lkO722JN+XrEQSO8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T8oFJt9DXLI7Dq+P3FUyBUHgoWY75uuwjRvIkZmfF04kJS+nrH0zaBjC1hT3o/u1l 4MF3Z3ERPAVll+4EVU4gwUeSdb+Fr4p417NpIFfbISOG3HgYJeB4dx0m/7KIY66u8H FRd+Ej6+oWFJC9WGNYdLQtWKXAE+FgCT4FjOT0tc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: rafael@kernel.org, Greg Kroah-Hartman Subject: [PATCH 22/36] driver core: bus: move dev_root out of struct bus_type Date: Mon, 13 Mar 2023 19:29:04 +0100 Message-Id: <20230313182918.1312597-22-gregkh@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230313182918.1312597-1-gregkh@linuxfoundation.org> References: <20230313182918.1312597-1-gregkh@linuxfoundation.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4073; i=gregkh@linuxfoundation.org; h=from:subject; bh=hPDqRd7gJAlE6q+8Dn7WGhvvs2+lkO722JN+XrEQSO8=; b=owGbwMvMwCRo6H6F97bub03G02pJDCn82VXZF83MrzAx7Uu9yn/i/MUad/4NXcsaRGZ2/smoO lN7xEm8I5aFQZCJQVZMkeXLNp6j+ysOKXoZ2p6GmcPKBDKEgYtTACZi9oJhwVpGxbyamMO6Oz8a CFsdVVkgN/nzK4b5CYZamqqWTkceV54t+vf8guk897enAQ== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1760280962279251617?= X-GMAIL-MSGID: =?utf-8?q?1760280962279251617?= Now that all accesses of dev_root is through the bus_get_dev_root() call, move the pointer out of struct bus_type and into the private dynamic structure, subsys_private. With this change, there is no modifiable portions of struct bus_type so it can be marked as a constant structure and moved to read-only memory. Cc: "Rafael J. Wysocki" Signed-off-by: Greg Kroah-Hartman --- drivers/base/base.h | 2 ++ drivers/base/bus.c | 28 ++++++++++++++++++++++------ include/linux/device/bus.h | 2 -- 3 files changed, 24 insertions(+), 8 deletions(-) diff --git a/drivers/base/base.h b/drivers/base/base.h index b055eba1ec30..f1034e27e651 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -27,6 +27,7 @@ * on this bus. * @bus - pointer back to the struct bus_type that this structure is associated * with. + * @dev_root: Default device to use as the parent. * * @glue_dirs - "glue" directory to put in-between the parent device to * avoid namespace conflicts @@ -49,6 +50,7 @@ struct subsys_private { struct blocking_notifier_head bus_notifier; unsigned int drivers_autoprobe:1; struct bus_type *bus; + struct device *dev_root; struct kset glue_dirs; struct class *class; diff --git a/drivers/base/bus.c b/drivers/base/bus.c index dd4b82d7510f..91a6b6b1fc49 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -935,8 +935,8 @@ void bus_unregister(const struct bus_type *bus) return; pr_debug("bus: '%s': unregistering\n", bus->name); - if (bus->dev_root) - device_unregister(bus->dev_root); + if (sp->dev_root) + device_unregister(sp->dev_root); bus_kobj = &sp->subsys.kobj; sysfs_remove_groups(bus_kobj, bus->bus_groups); @@ -1198,6 +1198,7 @@ static int subsys_register(struct bus_type *subsys, const struct attribute_group **groups, struct kobject *parent_of_root) { + struct subsys_private *sp; struct device *dev; int err; @@ -1205,6 +1206,12 @@ static int subsys_register(struct bus_type *subsys, if (err < 0) return err; + sp = bus_to_subsys(subsys); + if (!sp) { + err = -EINVAL; + goto err_sp; + } + dev = kzalloc(sizeof(struct device), GFP_KERNEL); if (!dev) { err = -ENOMEM; @@ -1223,7 +1230,8 @@ static int subsys_register(struct bus_type *subsys, if (err < 0) goto err_dev_reg; - subsys->dev_root = dev; + sp->dev_root = dev; + subsys_put(sp); return 0; err_dev_reg: @@ -1232,6 +1240,8 @@ static int subsys_register(struct bus_type *subsys, err_name: kfree(dev); err_dev: + subsys_put(sp); +err_sp: bus_unregister(subsys); return err; } @@ -1349,9 +1359,15 @@ bool bus_is_registered(const struct bus_type *bus) */ struct device *bus_get_dev_root(const struct bus_type *bus) { - if (bus) - return get_device(bus->dev_root); - return NULL; + struct subsys_private *sp = bus_to_subsys(bus); + struct device *dev_root; + + if (!sp) + return NULL; + + dev_root = get_device(sp->dev_root); + subsys_put(sp); + return dev_root; } EXPORT_SYMBOL_GPL(bus_get_dev_root); diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h index 6ce32ef4b8fd..c258e8770285 100644 --- a/include/linux/device/bus.h +++ b/include/linux/device/bus.h @@ -26,7 +26,6 @@ struct fwnode_handle; * * @name: The name of the bus. * @dev_name: Used for subsystems to enumerate devices like ("foo%u", dev->id). - * @dev_root: Default device to use as the parent. * @bus_groups: Default attributes of the bus. * @dev_groups: Default attributes of the devices on the bus. * @drv_groups: Default attributes of the device drivers on the bus. @@ -82,7 +81,6 @@ struct fwnode_handle; struct bus_type { const char *name; const char *dev_name; - struct device *dev_root; const struct attribute_group **bus_groups; const struct attribute_group **dev_groups; const struct attribute_group **drv_groups;