From patchwork Mon Mar 8 08:14:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Vaittinen, Matti" X-Patchwork-Id: 12121741 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 EAF4CC433E0 for ; Mon, 8 Mar 2021 08:15:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E4516513A for ; Mon, 8 Mar 2021 08:15:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231631AbhCHIPK (ORCPT ); Mon, 8 Mar 2021 03:15:10 -0500 Received: from mail-lj1-f182.google.com ([209.85.208.182]:38289 "EHLO mail-lj1-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231156AbhCHIOi (ORCPT ); Mon, 8 Mar 2021 03:14:38 -0500 Received: by mail-lj1-f182.google.com with SMTP id 2so14948324ljr.5; Mon, 08 Mar 2021 00:14:37 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=BsY7YkuLSTkyifbDrF2JneCtTyzv1UBxYFrackx4xR8=; b=YTiiDJY12idIvV5K6HY8/qDaqt67/BybdmHTXpQgax2SEqMPgIYBEjsM5BvUy+rf7d FEZehutzb1rRmBuJCOstWUU9S6qTQBihhpJRqAyFoAf/7C6q40rxAS2EOA09Fy5HE9pW hcXOHtxvnA2ne3vD4PWmcKlxXkKnBtcxdaZ9nCRLy/Ax657orZDbRXzz3qU2Rot7+cam 9eVX6iJ9EjgN2fPx1dsotdMK8ZhGvizqOoMiaOxyvo+WwDbSlwVA9kj5vQZyCalKnXAe DVm0ajKsW/cKydlO3WP0OA0YkOyIDfiWVbuQVeToVXpz7lWfct8qtorIK0EpjCtEki0q DeBg== X-Gm-Message-State: AOAM532IG3DKq2+gZBD4/UvzhEU/gcOpUbKm1vjZfLSLpT4pCur5GsgH Qza8gyjTxwGODuCHK0GDRT4= X-Google-Smtp-Source: ABdhPJy4xumvg0xGCoOKqEE8DnfFdePx7FGRoHfszIvelo6PtIuYKRw2B90h39CtVR+4XQkHZwtqzQ== X-Received: by 2002:a2e:2f0c:: with SMTP id v12mr12577254ljv.367.1615191276436; Mon, 08 Mar 2021 00:14:36 -0800 (PST) Received: from localhost.localdomain (dc7vkhyyyyyyyyyyyyycy-3.rev.dnainternet.fi. [2001:14ba:16e2:8300::4]) by smtp.gmail.com with ESMTPSA id d3sm1271836lfq.249.2021.03.08.00.14.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Mar 2021 00:14:36 -0800 (PST) Date: Mon, 8 Mar 2021 10:14:29 +0200 From: Matti Vaittinen To: matti.vaittinen@fi.rohmeurope.com, mazziesaccount@gmail.com Cc: MyungJoo Ham , Chanwoo Choi , Andy Gross , Bjorn Andersson , Jean Delvare , Guenter Roeck , Hans de Goede , Mark Gross , Sebastian Reichel , Chen-Yu Tsai , Liam Girdwood , Mark Brown , Wim Van Sebroeck , Matti Vaittinen , gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-hwmon@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-pm@vger.kernel.org, linux-watchdog@vger.kernel.org Subject: [RFC PATCH v2 1/8] workqueue: Add resource managed version of delayed work init Message-ID: <2ff44816b72a43f715d58552d2fadc1470e167d0.1615187284.git.matti.vaittinen@fi.rohmeurope.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org A few drivers which need a delayed work-queue must cancel work at driver detach. Some of those implement remove() solely for this purpose. Help drivers to avoid unnecessary remove and error-branch implementation by adding managed verision of delayed work initialization. This will also help drivers to avoid mixing manual and devm based unwinding when other resources are handled by devm. Signed-off-by: Matti Vaittinen --- include/linux/devm-helpers.h | 53 ++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 include/linux/devm-helpers.h diff --git a/include/linux/devm-helpers.h b/include/linux/devm-helpers.h new file mode 100644 index 000000000000..f64e0c9f3763 --- /dev/null +++ b/include/linux/devm-helpers.h @@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef __LINUX_DEVM_HELPERS_H +#define __LINUX_DEVM_HELPERS_H + +/* + * Functions which do automatically cancel operations or release resources upon + * driver detach. + * + * These should be helpful to avoid mixing the manual and devm-based resource + * management which can be source of annoying, rarely occurring, + * hard-to-reproduce bugs. + * + * Please take into account that devm based cancellation may be performed some + * time after the remove() is ran. + * + * Thus mixing devm and manual resource management can easily cause problems + * when unwinding operations with dependencies. IRQ scheduling a work in a queue + * is typical example where IRQs are often devm-managed and WQs are manually + * cleaned at remove(). If IRQs are not manually freed at remove() (and this is + * often the case when we use devm for IRQs) we have a period of time after + * remove() - and before devm managed IRQs are freed - where new IRQ may fire + * and schedule a work item which won't be cancelled because remove() was + * already ran. + */ + +#include +#include + +static inline void devm_delayed_work_drop(void *res) +{ + cancel_delayed_work_sync(res); +} + +/** + * devm_delayed_work_autocancel - Resource-managed work allocation + * @dev: Device which lifetime work is bound to + * @pdata: work to be cancelled when driver is detached + * + * Initialize work which is automatically cancelled when driver is detached. + * A few drivers need delayed work which must be cancelled before driver + * is detached to avoid accessing removed resources. + * devm_delayed_work_autocancel() can be used to omit the explicit + * cancelleation when driver is detached. + */ +static inline int devm_delayed_work_autocancel(struct device *dev, + struct delayed_work *w, + work_func_t worker) +{ + INIT_DELAYED_WORK(w, worker); + return devm_add_action(dev, devm_delayed_work_drop, w); +} + +#endif