From patchwork Mon Mar 22 01:38:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Torokhov X-Patchwork-Id: 1456348 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-i2c-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=Caa2gW8H; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4F3ccH08m3z9sWS for ; Mon, 22 Mar 2021 12:39:27 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229872AbhCVBix (ORCPT ); Sun, 21 Mar 2021 21:38:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52848 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230070AbhCVBig (ORCPT ); Sun, 21 Mar 2021 21:38:36 -0400 Received: from mail-pg1-x529.google.com (mail-pg1-x529.google.com [IPv6:2607:f8b0:4864:20::529]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 43DB1C061574; Sun, 21 Mar 2021 18:38:36 -0700 (PDT) Received: by mail-pg1-x529.google.com with SMTP id v2so7592995pgk.11; Sun, 21 Mar 2021 18:38:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition; bh=qlNbZGIMBNb9SgIMukwug5lwHWy/u/7OkPnoFKIJhWc=; b=Caa2gW8HOFDauVViHY8sYagds7MPgYnkyNwAz6tb8IIRTHJ+hAuHzMe6Qk51Js2+oG VL9VQtewQzIHhPKci2NAcTq9nX6/Y2U6p3rvkTaoINGp8FTRd03SBu24wDHhJNp42KNv Pr3+L4VRSeUrt6MWKqTWAYCFHHL1Is1MbZ3phZ7xK2+JpuORZn8gczbHFilgBmJrITKz 6GmKNzmt2OAQo/++sXzHB13vO3FivmUiC6J6cN24ZyYHHC+sVVo/l3+nvadB7oUnXMlT QroO5vsiz2u/C/RMdIsrmtkK5l4UmXGM084MqppJK57Q+G/qIEfuhN3YHlMAl51DLOQp Tncw== 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:mime-version :content-disposition; bh=qlNbZGIMBNb9SgIMukwug5lwHWy/u/7OkPnoFKIJhWc=; b=SEQmMNgIKH17neQT4Mxb3Iq9ejVL0qtiBqneEIQGUwkp/NqW7iDdmoO+E9rdPph6QR u2f5jDyXWZjNEpOQmZMyvOujDWW7yRTwF7Bb+SVsL0VIay3+SzcY+SIXSSOR5AcasQzE eouT4QW1m04KXpUDQMZIL0lxVdzajMgPH9FP+Gy34iwJSfbPreM/qt9oSIwQfURWAxuT PNtpElgL2CpfNDUElkHxmp7AJSsfiS3ctDYPa0uKo9NZXoCNs07VU+SblZbMzBHGubuA DHixL7FddATesaUGqb2SnplOTq31/dbUoTGCD/lt1/ax3hGQ3Esr88zbi1sbT7p4YNXG vUPQ== X-Gm-Message-State: AOAM531VsF95JaR8e5LCFAfnTfKXeVOZjCuK04He5kLZZwSNplJYCRKv XtmpZKdkaLrWyvIa1xTIb1idowUBJRE= X-Google-Smtp-Source: ABdhPJy2Z9jhoTkhERKqWQPcWZijOh2LKMt6RqtnAm/8gVX3S7w+GYcFJL+FA28vLbYuKxewZANLcg== X-Received: by 2002:a63:cd09:: with SMTP id i9mr21091503pgg.407.1616377115745; Sun, 21 Mar 2021 18:38:35 -0700 (PDT) Received: from google.com ([2620:15c:202:201:85c2:9df1:533a:87e9]) by smtp.gmail.com with ESMTPSA id v18sm11943846pfn.117.2021.03.21.18.38.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 21 Mar 2021 18:38:34 -0700 (PDT) Date: Sun, 21 Mar 2021 18:38:32 -0700 From: Dmitry Torokhov To: Wolfram Sang Cc: Jeff LaBundy , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] i2c: ensure timely release of driver-allocated resources Message-ID: MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org More and more drivers rely on devres to manage their resources, however if bus' probe() and release() methods are not trivial and control some of resources as well (for example enable or disable clocks, or attach device to a power domain), we need to make sure that driver-allocated resources are released immediately after driver's remove() method returns, and not postponed until driver core gets around to releasing resources. To fix that we open a new devres group before calling driver's probe() and explicitly release it when we return from driver's remove(). Tested-by: Jeff LaBundy Signed-off-by: Dmitry Torokhov --- Note that this problem is not I2C-specific and I will be sending patches for other buses as well. drivers/i2c/i2c-core-base.c | 21 ++++++++++++++++++++- include/linux/i2c.h | 3 +++ 2 files changed, 23 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 63ebf722a424..b38ecd888b90 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -518,6 +518,13 @@ static int i2c_device_probe(struct device *dev) if (status) goto err_clear_wakeup_irq; + client->devres_group_id = devres_open_group(&client->dev, NULL, + GFP_KERNEL); + if (!client->devres_group_id) { + status = -ENOMEM; + goto err_detach_pm_domain; + } + /* * When there are no more users of probe(), * rename probe_new to probe. @@ -530,11 +537,21 @@ static int i2c_device_probe(struct device *dev) else status = -EINVAL; + /* + * Note that we are not closing the devres group opened above so + * even resources that were attached to the device after probe is + * run are released when i2c_device_remove() is executed. This is + * needed as some drivers would allocate additional resources, + * for example when updating firmware. + */ + if (status) - goto err_detach_pm_domain; + goto err_release_driver_resources; return 0; +err_release_driver_resources: + devres_release_group(&client->dev, client->devres_group_id); err_detach_pm_domain: dev_pm_domain_detach(&client->dev, true); err_clear_wakeup_irq: @@ -563,6 +580,8 @@ static int i2c_device_remove(struct device *dev) dev_warn(dev, "remove failed (%pe), will be ignored\n", ERR_PTR(status)); } + devres_release_group(&client->dev, client->devres_group_id); + dev_pm_domain_detach(&client->dev, true); dev_pm_clear_wake_irq(&client->dev); diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 56622658b215..5d1f11c0deaa 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -306,6 +306,8 @@ struct i2c_driver { * userspace_devices list * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter * calls it to pass on slave events to the slave driver. + * @devres_group_id: id of the devres group that will be created for resources + * acquired when probing this device. * * An i2c_client identifies a single device (i.e. chip) connected to an * i2c bus. The behaviour exposed to Linux is defined by the driver @@ -334,6 +336,7 @@ struct i2c_client { #if IS_ENABLED(CONFIG_I2C_SLAVE) i2c_slave_cb_t slave_cb; /* callback for slave mode */ #endif + void *devres_group_id; /* ID of probe devres group */ }; #define to_i2c_client(d) container_of(d, struct i2c_client, dev)