From patchwork Fri Feb 2 12:18:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nuno Sa via B4 Relay X-Patchwork-Id: 769269 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 550F414076C; Fri, 2 Feb 2024 12:18:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706876302; cv=none; b=puxDza5FWsxvOWletooWE9YMncnk1vS3Vow11lfhwa+jZr+WK6v1GLiRS0we1ahNMcMW2L6v83M/CccW4MlensUkufQjGJ2Y2N9V26H9Nzi9FhflfD4qBSkRSjCGfnMeOYZgDuO92364X1FS+lvnqlJ4kbCccrBhgFVrOaYb7QU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706876302; c=relaxed/simple; bh=cDD6zWE+hIAQdurFS+rSICTH3h1uOHnIQoJ80Fb5RoU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=V67XxXrdhOUzjM6Nh7uPFmirMGl8KoynGVPexnGs7Vrl/tul+JUXnQtsiQFV2ranqt/BuOXI1PgSmbYtMYUW4uhwz0XgWf00PB4fTEUcuHDLe7R3kjQ3n8ejJSmXRWafxpItVphd2L0g6Ju5OALN3JTBRJw4WmppKUA9sS7bZAY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AoZV5JNv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AoZV5JNv" Received: by smtp.kernel.org (Postfix) with ESMTPS id EA050C433F1; Fri, 2 Feb 2024 12:18:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706876302; bh=cDD6zWE+hIAQdurFS+rSICTH3h1uOHnIQoJ80Fb5RoU=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=AoZV5JNv3oQO7IebuQ+al5XeD5XyLhj9FV4qgqVMmvTc2AHrq8seQEQec6+vns13S OrpsotHKZ8p6k3UUVmjMRo0L1vf9jImRW5GKfWBVLWQqeVnREKuq5NUqqPPGRWBuUC 6gAk26wDcIBcK1RJKZ9SgkZN/DDQDEr8nosZSfDiYjZ/sMIjSXWriLB2eFyV540KOD OAYg/toV4ky+RxvYujwYSPD1cW0ktLyVirTOqE1Y7fPjLySH3qT90i7qs33HsVV01i eOU0dq2xTSNKEpMorLGyzPfWh/xkPxTS6eQkwNrkYgepL1hK5GeTbz0B1Zf6D9xhQp HqvAhUU9KW2NA== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC173C48291; Fri, 2 Feb 2024 12:18:21 +0000 (UTC) From: Nuno Sa via B4 Relay Date: Fri, 02 Feb 2024 13:18:16 +0100 Subject: [PATCH 1/2] driver: core: add dedicated workqueue for devlink removal Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240202-fix-device-links-overlays-v1-1-f9fd1404c8e2@analog.com> References: <20240202-fix-device-links-overlays-v1-0-f9fd1404c8e2@analog.com> In-Reply-To: <20240202-fix-device-links-overlays-v1-0-f9fd1404c8e2@analog.com> To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Frank Rowand , Rob Herring , Andy Shevchenko , Daniel Scally , Heikki Krogerus , Sakari Ailus , Len Brown Cc: linux-acpi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1706876300; l=3622; i=nuno.sa@analog.com; s=20231116; h=from:subject:message-id; bh=ByQW6bRhqckZ/DlDF0eHD/SVHr3IYmtWZF3VkOkvgCw=; b=WICzQqU/L3gsEQRCsjjuaAvWQHaT7MtrCBmtTUWoXIlARhre7lov5EEkAoHQ++K02ag0qs27w lA2lR3S4/yjDPZnECukErBUw0XqUC3wNoIIEI7o9or9qJo1hbLkniV6 X-Developer-Key: i=nuno.sa@analog.com; a=ed25519; pk=3NQwYA013OUYZsmDFBf8rmyyr5iQlxV/9H4/Df83o1E= X-Endpoint-Received: by B4 Relay for nuno.sa@analog.com/20231116 with auth_id=100 X-Original-From: Nuno Sa Reply-To: From: Nuno Sa Let's use a dedicated queue for devlinks since releasing a link happens asynchronously but some code paths, like DT overlays, have some expectations regarding the of_node when being removed (the refcount must be 1). Given how devlinks are released that cannot be assured. Hence, add a dedicated queue so that it's easy to sync against devlinks removal. While at it, make sure to explicitly include . Signed-off-by: Nuno Sa --- drivers/base/core.c | 33 +++++++++++++++++++++++++++++---- include/linux/fwnode.h | 1 + 2 files changed, 30 insertions(+), 4 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 14d46af40f9a..06e7766b5227 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -31,6 +31,7 @@ #include #include #include /* for dma_default_coherent */ +#include #include "base.h" #include "physical_location.h" @@ -44,6 +45,7 @@ static bool fw_devlink_is_permissive(void); static void __fw_devlink_link_to_consumers(struct device *dev); static bool fw_devlink_drv_reg_done; static bool fw_devlink_best_effort; +static struct workqueue_struct *devlink_release_queue __ro_after_init; /** * __fwnode_link_add - Create a link between two fwnode_handles. @@ -235,6 +237,11 @@ static void __fw_devlink_pickup_dangling_consumers(struct fwnode_handle *fwnode, __fw_devlink_pickup_dangling_consumers(child, new_sup); } +void fwnode_links_flush_queue(void) +{ + flush_workqueue(devlink_release_queue); +} + static DEFINE_MUTEX(device_links_lock); DEFINE_STATIC_SRCU(device_links_srcu); @@ -531,9 +538,10 @@ static void devlink_dev_release(struct device *dev) * It may take a while to complete this work because of the SRCU * synchronization in device_link_release_fn() and if the consumer or * supplier devices get deleted when it runs, so put it into the "long" - * workqueue. + * devlink workqueue. + * */ - queue_work(system_long_wq, &link->rm_work); + queue_work(devlink_release_queue, &link->rm_work); } static struct class devlink_class = { @@ -636,10 +644,27 @@ static int __init devlink_class_init(void) return ret; ret = class_interface_register(&devlink_class_intf); - if (ret) + if (ret) { + class_unregister(&devlink_class); + return ret; + } + + /* + * Using a dedicated queue for devlinks since releasing a link happens + * asynchronously but some code paths, like DT overlays, have some + * expectations regarding the of_node when being removed (the refcount + * must be 1). Given how devlinks are released that cannot be assured. + * Hence, add a dedicated queue so that it's easy to sync against + * devlinks removal. + */ + devlink_release_queue = alloc_workqueue("devlink_release", 0, 0); + if (!devlink_release_queue) { + class_interface_unregister(&devlink_class_intf); class_unregister(&devlink_class); + return -ENODEV; + } - return ret; + return 0; } postcore_initcall(devlink_class_init); diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h index 2a72f55d26eb..017b170e9903 100644 --- a/include/linux/fwnode.h +++ b/include/linux/fwnode.h @@ -213,5 +213,6 @@ extern bool fw_devlink_is_strict(void); int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup); void fwnode_links_purge(struct fwnode_handle *fwnode); void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode); +void fwnode_links_flush_queue(void); #endif From patchwork Fri Feb 2 12:18:17 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nuno Sa via B4 Relay X-Patchwork-Id: 769551 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 550BC140764; Fri, 2 Feb 2024 12:18:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706876302; cv=none; b=GEWkAn/ijUwfmfQeKl3ZP01nUIq7U96qToITqv+PiiAnHd0DiOXB2hXB9BglQ1HXorkayKVtYG12sfr/9InVjSE/6xvF4c4X8F+2lTGxjqMUOKRyKitId3V+zdUznUqxeqUhBfHuHPfJV6ohAQ9nbV4YK6FBVdT6n7XqHkUTkFE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706876302; c=relaxed/simple; bh=76bLnTFW8hOss6IF1pWTx33Eugtw/u1ls0YA9hmCWJA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=RaBj+9p5EhKXqYkWGDnfEaYTD/2+l3/BYtI1FZifJdXaJj1J1YYcKibATilsSWg/VHcr9xWsp0Kz7ltXxfMZTFVMSUbrdj5Yo9hEu5ecYHJlM/hkWqLfF4532Mw3XbpF9/ki9+bt98rXyOerQQ7RXtx4f5Ty+wg7D5PgLQ+NQKs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XS91VSIV; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XS91VSIV" Received: by smtp.kernel.org (Postfix) with ESMTPS id F3AF3C433B1; Fri, 2 Feb 2024 12:18:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706876302; bh=76bLnTFW8hOss6IF1pWTx33Eugtw/u1ls0YA9hmCWJA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=XS91VSIVxeAq9Ho4N5W/CiepsN+55y/voO+51FzBqNFFbP9eddOWk7W6ktq2lZ+5+ Pp0SCqzYLiPKNdI7j8wf4UTAgc+S/J77Bf0hDS8RQUZIKOiGV42lZ/TSG/z3izPhiw uadBuCu+CYz0jxWTcNNaLyHahwT4fQIIZoa13E89CF0alxGxlDm9OnM8UNq7f9Rjek h9ijT1J7Plz98HwyqNFlcPgrk0NsBdGoyW7P+0lQVSU9Xd6UN/QjgprS0ogBFwSiIF B27mAYOf3/XH8EuxXnITW/F37jIQXjp2wa0gl7QQYfVGUG1/J2+hazmBU/m34qfYQr SilZ8SUdPBhVQ== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id D61A8C47DB3; Fri, 2 Feb 2024 12:18:21 +0000 (UTC) From: Nuno Sa via B4 Relay Date: Fri, 02 Feb 2024 13:18:17 +0100 Subject: [PATCH 2/2] of: dynamic: flush devlinks workqueue before destroying the changeset Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240202-fix-device-links-overlays-v1-2-f9fd1404c8e2@analog.com> References: <20240202-fix-device-links-overlays-v1-0-f9fd1404c8e2@analog.com> In-Reply-To: <20240202-fix-device-links-overlays-v1-0-f9fd1404c8e2@analog.com> To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Frank Rowand , Rob Herring , Andy Shevchenko , Daniel Scally , Heikki Krogerus , Sakari Ailus , Len Brown Cc: linux-acpi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1706876300; l=1506; i=nuno.sa@analog.com; s=20231116; h=from:subject:message-id; bh=YDuksPxVzpgUXsXtMiptrKAHNtqa9E4wT61h67KKExU=; b=ZZzDh6w2p09vAdpaA/tKnsT3Ui0/BIBnmAmI6LdOVcWud7O6pG7mMOAa9At/XeR3mGQi7zAsu 0e7xJAbQW2cCDWx1T2sT1C8IFd2yKgLf/WrOHH3wwaavzpt33PL6veD X-Developer-Key: i=nuno.sa@analog.com; a=ed25519; pk=3NQwYA013OUYZsmDFBf8rmyyr5iQlxV/9H4/Df83o1E= X-Endpoint-Received: by B4 Relay for nuno.sa@analog.com/20231116 with auth_id=100 X-Original-From: Nuno Sa Reply-To: From: Nuno Sa Device links will drop their supplier + consumer refcounts asynchronously. That means that the refcount of the of_node attached to these devices will also be dropped asynchronously and so we cannot guarantee the DT overlay assumption that the of_node refcount must be 1 in __of_changeset_entry_destroy(). Given the above, call the new fwnode_links_flush_queue() helper to flush the devlink workqueue so we can be sure that all links are dropped before doing the proper checks. Signed-off-by: Nuno Sa --- drivers/of/dynamic.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c index 3bf27052832f..b7153c72c9c9 100644 --- a/drivers/of/dynamic.c +++ b/drivers/of/dynamic.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "of_private.h" @@ -518,6 +519,13 @@ EXPORT_SYMBOL(of_changeset_create_node); static void __of_changeset_entry_destroy(struct of_changeset_entry *ce) { + /* + * device links drop their device references (and hence their of_node + * references) asynchronously on a dedicated workqueue. Hence we need + * to flush it to make sure everything is done before doing the below + * checks. + */ + fwnode_links_flush_queue(); if (ce->action == OF_RECONFIG_ATTACH_NODE && of_node_check_flag(ce->np, OF_OVERLAY)) { if (kref_read(&ce->np->kobj.kref) > 1) {