From patchwork Mon Feb 5 12:09:32 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: 770427 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 ADEF71BDE0; Mon, 5 Feb 2024 12:09:34 +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=1707134974; cv=none; b=ROvhW6XXnVxfB07B1yWOKnB7TfFTCec9AVRtZ7mV4dxzsOaT2mY7UuclLZ/+AerZGjM9tQqiIyMVmhGFUXarpLScszCeE+UUN9qo897moTwt/5k/8qj8Wsp9Sxw+bI1GOv4Ga+U1jbbXovV29HYO6b98gqVAYKoUo3qYhn7nBS8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707134974; c=relaxed/simple; bh=HewPtQWo7tWPORgACWT0isq/+RxLYJgNeixGj5Mul8E=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=pXVvXk2xzOQKA7+xVm+o0wNwJIpQi4kJ6CskiwvmqA4dz5RZBC+QoMk3p4R0lUomVGd+C+lCNIlxWg7LU5tNTyaXbGlRuYPL5ebqcbDXpb+d8PURjUeEf7nq07FT0rpm6W9b+Cixlo3lbuJnFWFKME7sLRrEyH6v/XcX4A0+6SQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=F/4eaYIu; 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="F/4eaYIu" Received: by smtp.kernel.org (Postfix) with ESMTPS id 2C586C43390; Mon, 5 Feb 2024 12:09:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1707134974; bh=HewPtQWo7tWPORgACWT0isq/+RxLYJgNeixGj5Mul8E=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=F/4eaYIunF6+IO8ZnDsUSI5qkGmgPLG9wJIOI2d/RnTcXpfPIIJAdcWADdPgx8qoN knAkraTNfKt+W2lrZAvWvf8i2D1LO+Qdk3Q+nMxbzozLw2u6fx9XJi+BuS36DR0HB0 Bwjf0TyGIbgi9luqXQOLYSPr8tTv5FhU0orBZxiGP08bhYWue7AZxe3uGy77h7hhhx y/yjnjFbbxkkb0uZEEUbejcc2s+T08/cIoGRrQiYt2RP8/S7O4ZMcmwZwf3lWFQOvt n2NMOVd5IQVE4ptuQS/ZXsZB9Y9D+R8vhyw8tczM0c0oXayGQ6J8pcJyvbFpW7BO5J NpN/T3cMjD+pw== 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 19A4AC48298; Mon, 5 Feb 2024 12:09:34 +0000 (UTC) From: Nuno Sa via B4 Relay Date: Mon, 05 Feb 2024 13:09:32 +0100 Subject: [PATCH v2 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: <20240205-fix-device-links-overlays-v2-1-5344f8c79d57@analog.com> References: <20240205-fix-device-links-overlays-v2-0-5344f8c79d57@analog.com> In-Reply-To: <20240205-fix-device-links-overlays-v2-0-5344f8c79d57@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=1707134972; l=3618; i=nuno.sa@analog.com; s=20231116; h=from:subject:message-id; bh=04lEYRnimMPlgUkTJm2JRaX4KnXuISPMtOvIVrmGT4w=; b=lwfkR/KxiRZUJunDSN14CeU4IP626N9hjJ6EcdvfTO3/wwBg6qH6hBZdyr82MOG6KDrEutXuL YwtUzVGk2I6DoMF8F9GU7korVSTuKL/kHovORS5XXoFa5y3Tbg+Bjzz 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 | 32 ++++++++++++++++++++++++++++---- include/linux/fwnode.h | 1 + 2 files changed, 29 insertions(+), 4 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 14d46af40f9a..4bb9c10489ed 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 +237,12 @@ 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) +{ + if (devlink_release_queue) + flush_workqueue(devlink_release_queue); +} + static DEFINE_MUTEX(device_links_lock); DEFINE_STATIC_SRCU(device_links_srcu); @@ -531,9 +539,13 @@ 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 (in case we could allocate one). + * */ - queue_work(system_long_wq, &link->rm_work); + if (devlink_release_queue) + queue_work(devlink_release_queue, &link->rm_work); + else + device_link_release_fn(&link->rm_work); } static struct class devlink_class = { @@ -636,10 +648,22 @@ 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; + } - 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); + + 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 Mon Feb 5 12:09:33 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: 770127 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 ADEB61BDD9; Mon, 5 Feb 2024 12:09:34 +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=1707134974; cv=none; b=OhS4X3pp3w7TsXsPc8DVVxNNq9wSZmniK6KCFi4navZyLtKTxLTEJnD8Glqyj0YdpTUgfji4W2/70xX40rKW/lNYMODHHoHcbQ4eI5RbWdLbgBoHCNY3daundtn9NO0HpUYBV669xs2HIEKWZ4VTpKAreF4FTTrSoiC5kZyh+rM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707134974; c=relaxed/simple; bh=76bLnTFW8hOss6IF1pWTx33Eugtw/u1ls0YA9hmCWJA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Ca8Dkl/FhF3QKsk7zml+ZdrALFX534sntgNGbhR3zrqEjCzwDesYjMEFuBQ17CIMvAB6xl5MNic3thf+cUwE+JGVIi++6LOFc/Scua/Sy5XPvqF7mDoyOOWNua4MyXdpMiUGcEHNtq5fAZ6GnDLx17mitDNBnuRJwzNv8v4u5Sw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BeEkOPAo; 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="BeEkOPAo" Received: by smtp.kernel.org (Postfix) with ESMTPS id 45979C433B1; Mon, 5 Feb 2024 12:09:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1707134974; bh=76bLnTFW8hOss6IF1pWTx33Eugtw/u1ls0YA9hmCWJA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=BeEkOPAoDv3chM+cAnfF5sgZRJD+P+xxeL/K+BBHS5at2/1Gi2+l1bWs8aaYvPucf XcoXBie0Jn+6ZWjon2DIURx5TZvYoGVQSG8d13zNY9HdU+rMJyAUDOehijidCe08s7 goBwyQh8IlalNMRGy8mubR47Se4m+W4BD1MEyxRrI6DG861k4xIiI0xyIZwCsHI+aC kSYsjcquM/yFejppnINsiPz6ImRnpzE1JMqfdcoCZricpEO84Uuc7ePwsSH/UzpNtx 4Op3VGcVQO+8mpnEQ4CW0rNdz8ZZuvZOOtKxYPhSiXZSV0MpDrETq5mibcvy7wQAE7 s09GZ1V+VXGGg== 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 2518FC4828D; Mon, 5 Feb 2024 12:09:34 +0000 (UTC) From: Nuno Sa via B4 Relay Date: Mon, 05 Feb 2024 13:09:33 +0100 Subject: [PATCH v2 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: <20240205-fix-device-links-overlays-v2-2-5344f8c79d57@analog.com> References: <20240205-fix-device-links-overlays-v2-0-5344f8c79d57@analog.com> In-Reply-To: <20240205-fix-device-links-overlays-v2-0-5344f8c79d57@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=1707134972; l=1506; i=nuno.sa@analog.com; s=20231116; h=from:subject:message-id; bh=YDuksPxVzpgUXsXtMiptrKAHNtqa9E4wT61h67KKExU=; b=+pR9xIxPkbxkT8MxATu4NfCBUJ+zzK6rP+cyMoqKYeDDvSxTJi8Gd3uvMlCO1CEC8rqyBMLCI WWMLTeb8A1LDHRH9Rh6EZ0RqMEszqHesQn9jA8kbQP8zEix/vgTjyD3 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) {