From patchwork Fri Apr 22 03:01:24 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tetsuo Handa X-Patchwork-Id: 12822702 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 476B8C433EF for ; Fri, 22 Apr 2022 03:02:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1443639AbiDVDEt (ORCPT ); Thu, 21 Apr 2022 23:04:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231341AbiDVDEr (ORCPT ); Thu, 21 Apr 2022 23:04:47 -0400 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C92EF4D240 for ; Thu, 21 Apr 2022 20:01:54 -0700 (PDT) Received: from fsav116.sakura.ne.jp (fsav116.sakura.ne.jp [27.133.134.243]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 23M31OSk038755; Fri, 22 Apr 2022 12:01:24 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav116.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav116.sakura.ne.jp); Fri, 22 Apr 2022 12:01:24 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav116.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 23M31Otc038751 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Fri, 22 Apr 2022 12:01:24 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: <7390d51f-60e2-3cee-5277-b819a55ceabe@I-love.SAKURA.ne.jp> Date: Fri, 22 Apr 2022 12:01:24 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Content-Language: en-US To: Loic Poulain , Sergey Ryazanov , Johannes Berg , "David S. Miller" , Jakub Kicinski , Paolo Abeni Cc: Network Development From: Tetsuo Handa Subject: [PATCH v2] wwan_hwsim: Avoid flush_scheduled_work() usage Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Flushing system-wide workqueues is dangerous and will be forbidden. Replace system_wq with local wwan_wq. While we are at it, make err_clean_devs: label of wwan_hwsim_init() behave like wwan_hwsim_exit(), for it is theoretically possible to call wwan_hwsim_debugfs_devcreate_write()/wwan_hwsim_debugfs_devdestroy_write() by the moment wwan_hwsim_init_devs() returns. Link: https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa Reviewed-by: Sergey Ryazanov Reviewed-by: Loic Poulain --- Changes in v2: Keep flush_workqueue(wwan_wq) explicit in order to match the comment. Make error path of wwan_hwsim_init() identical to wwan_hwsim_exit(). drivers/net/wwan/wwan_hwsim.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/drivers/net/wwan/wwan_hwsim.c b/drivers/net/wwan/wwan_hwsim.c index 5b62cf3b3c42..fad642f9ffd8 100644 --- a/drivers/net/wwan/wwan_hwsim.c +++ b/drivers/net/wwan/wwan_hwsim.c @@ -33,6 +33,7 @@ static struct dentry *wwan_hwsim_debugfs_devcreate; static DEFINE_SPINLOCK(wwan_hwsim_devs_lock); static LIST_HEAD(wwan_hwsim_devs); static unsigned int wwan_hwsim_dev_idx; +static struct workqueue_struct *wwan_wq; struct wwan_hwsim_dev { struct list_head list; @@ -371,7 +372,7 @@ static ssize_t wwan_hwsim_debugfs_portdestroy_write(struct file *file, * waiting this callback to finish in the debugfs_remove() call. So, * use workqueue. */ - schedule_work(&port->del_work); + queue_work(wwan_wq, &port->del_work); return count; } @@ -416,7 +417,7 @@ static ssize_t wwan_hwsim_debugfs_devdestroy_write(struct file *file, * waiting this callback to finish in the debugfs_remove() call. So, * use workqueue. */ - schedule_work(&dev->del_work); + queue_work(wwan_wq, &dev->del_work); return count; } @@ -506,9 +507,15 @@ static int __init wwan_hwsim_init(void) if (wwan_hwsim_devsnum < 0 || wwan_hwsim_devsnum > 128) return -EINVAL; + wwan_wq = alloc_workqueue("wwan_wq", 0, 0); + if (!wwan_wq) + return -ENOMEM; + wwan_hwsim_class = class_create(THIS_MODULE, "wwan_hwsim"); - if (IS_ERR(wwan_hwsim_class)) - return PTR_ERR(wwan_hwsim_class); + if (IS_ERR(wwan_hwsim_class)) { + err = PTR_ERR(wwan_hwsim_class); + goto err_wq_destroy; + } wwan_hwsim_debugfs_topdir = debugfs_create_dir("wwan_hwsim", NULL); wwan_hwsim_debugfs_devcreate = @@ -523,9 +530,13 @@ static int __init wwan_hwsim_init(void) return 0; err_clean_devs: + debugfs_remove(wwan_hwsim_debugfs_devcreate); /* Avoid new devs */ wwan_hwsim_free_devs(); + flush_workqueue(wwan_wq); /* Wait deletion works completion */ debugfs_remove(wwan_hwsim_debugfs_topdir); class_destroy(wwan_hwsim_class); +err_wq_destroy: + destroy_workqueue(wwan_wq); return err; } @@ -534,9 +545,10 @@ static void __exit wwan_hwsim_exit(void) { debugfs_remove(wwan_hwsim_debugfs_devcreate); /* Avoid new devs */ wwan_hwsim_free_devs(); - flush_scheduled_work(); /* Wait deletion works completion */ + flush_workqueue(wwan_wq); /* Wait deletion works completion */ debugfs_remove(wwan_hwsim_debugfs_topdir); class_destroy(wwan_hwsim_class); + destroy_workqueue(wwan_wq); } module_init(wwan_hwsim_init);