From patchwork Fri Mar 12 12:24:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Nicolas Saenz Julienne X-Patchwork-Id: 12134503 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=-17.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 163AFC433DB for ; Fri, 12 Mar 2021 12:27:13 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9AAD564FEE for ; Fri, 12 Mar 2021 12:27:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9AAD564FEE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=iI7mJzC13DXSpmTZELHafdAPehkqajxqXjGEmvkVPto=; b=nbyiosKwgIjetajhmnbCMhXeS N+aaaOfqjYzPjFbHv/olzZTzDyvJhpLyoyiQhczeR6GjG4Mu2cnRyMw4OMVHZt3wLpPP9dw5bxgXK ZqnwmqYUk9ZA36KMy09GZh6LQrh8TzaHIFVlux7H99l0x4yqRgviwuNjEDk9Y3dsQBW8KONYsKbE5 raeFn1vcPXdkzuL8EXIqueX7cU5JDcAloCBM2J4yyHKOOiCd4oo1+vyDHHG3LmlGcAbnrfRyR3xJK bokaTtw2FAY0dor4cPdc4BI8ZGFOrsIViLgIMl7IGidXX3TFf7vTImJRO/XozR1Xljdu4weOxEkQn vH2ABis+A==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lKgrE-00BOPu-Hj; Fri, 12 Mar 2021 12:25:32 +0000 Received: from mx2.suse.de ([195.135.220.15]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lKgr1-00BOJz-P8; Fri, 12 Mar 2021 12:25:21 +0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A5FD6B0B3; Fri, 12 Mar 2021 12:25:17 +0000 (UTC) From: Nicolas Saenz Julienne To: u.kleine-koenig@pengutronix.de Cc: f.fainelli@gmail.com, linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, wahrenst@gmx.net, linux-input@vger.kernel.org, dmitry.torokhov@gmail.com, gregkh@linuxfoundation.org, devel@driverdev.osuosl.org, p.zabel@pengutronix.de, linux-gpio@vger.kernel.org, linus.walleij@linaro.org, linux-clk@vger.kernel.org, sboyd@kernel.org, linux-rpi-kernel@lists.infradead.org, bgolaszewski@baylibre.com, andy.shevchenko@gmail.com, Nicolas Saenz Julienne Subject: [PATCH v8 01/11] firmware: raspberrypi: Keep count of all consumers Date: Fri, 12 Mar 2021 13:24:44 +0100 Message-Id: <20210312122454.24480-2-nsaenzjulienne@suse.de> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210312122454.24480-1-nsaenzjulienne@suse.de> References: <20210312122454.24480-1-nsaenzjulienne@suse.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210312_122520_058210_71488CD9 X-CRM114-Status: GOOD ( 18.14 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When unbinding the firmware device we need to make sure it has no consumers left. Otherwise we'd leave them with a firmware handle pointing at freed memory. Keep a reference count of all consumers and introduce rpi_firmware_put() which will permit automatically decrease the reference count upon unbinding consumer drivers. Suggested-by: Uwe Kleine-König Signed-off-by: Nicolas Saenz Julienne Reviewed-by: Florian Fainelli Reviewed-by: Stephen Boyd Reviewed-by: Bartosz Golaszewski --- Changes since v5: - Add comment to avoid people blindly switching the memory allocation to the devm variant. - Fix function documentation as per Florian's comment. Changes since v3: - Use kref instead of waiting on refcount drivers/firmware/raspberrypi.c | 40 ++++++++++++++++++++-- include/soc/bcm2835/raspberrypi-firmware.h | 2 ++ 2 files changed, 39 insertions(+), 3 deletions(-) diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c index 30259dc9b805..b65e4c495772 100644 --- a/drivers/firmware/raspberrypi.c +++ b/drivers/firmware/raspberrypi.c @@ -7,6 +7,7 @@ */ #include +#include #include #include #include @@ -27,6 +28,8 @@ struct rpi_firmware { struct mbox_chan *chan; /* The property channel. */ struct completion c; u32 enabled; + + struct kref consumers; }; static DEFINE_MUTEX(transaction_lock); @@ -225,12 +228,31 @@ static void rpi_register_clk_driver(struct device *dev) -1, NULL, 0); } +static void rpi_firmware_delete(struct kref *kref) +{ + struct rpi_firmware *fw = container_of(kref, struct rpi_firmware, + consumers); + + mbox_free_channel(fw->chan); + kfree(fw); +} + +void rpi_firmware_put(struct rpi_firmware *fw) +{ + kref_put(&fw->consumers, rpi_firmware_delete); +} +EXPORT_SYMBOL_GPL(rpi_firmware_put); + static int rpi_firmware_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct rpi_firmware *fw; - fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL); + /* + * Memory will be freed by rpi_firmware_delete() once all users have + * released their firmware handles. Don't use devm_kzalloc() here. + */ + fw = kzalloc(sizeof(*fw), GFP_KERNEL); if (!fw) return -ENOMEM; @@ -247,6 +269,7 @@ static int rpi_firmware_probe(struct platform_device *pdev) } init_completion(&fw->c); + kref_init(&fw->consumers); platform_set_drvdata(pdev, fw); @@ -275,7 +298,8 @@ static int rpi_firmware_remove(struct platform_device *pdev) rpi_hwmon = NULL; platform_device_unregister(rpi_clk); rpi_clk = NULL; - mbox_free_channel(fw->chan); + + rpi_firmware_put(fw); return 0; } @@ -284,16 +308,26 @@ static int rpi_firmware_remove(struct platform_device *pdev) * rpi_firmware_get - Get pointer to rpi_firmware structure. * @firmware_node: Pointer to the firmware Device Tree node. * + * The reference to rpi_firmware has to be released with rpi_firmware_put(). + * * Returns NULL is the firmware device is not ready. */ struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node) { struct platform_device *pdev = of_find_device_by_node(firmware_node); + struct rpi_firmware *fw; if (!pdev) return NULL; - return platform_get_drvdata(pdev); + fw = platform_get_drvdata(pdev); + if (!fw) + return NULL; + + if (!kref_get_unless_zero(&fw->consumers)) + return NULL; + + return fw; } EXPORT_SYMBOL_GPL(rpi_firmware_get); diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h index cc9cdbc66403..fdfef7fe40df 100644 --- a/include/soc/bcm2835/raspberrypi-firmware.h +++ b/include/soc/bcm2835/raspberrypi-firmware.h @@ -140,6 +140,7 @@ int rpi_firmware_property(struct rpi_firmware *fw, u32 tag, void *data, size_t len); int rpi_firmware_property_list(struct rpi_firmware *fw, void *data, size_t tag_size); +void rpi_firmware_put(struct rpi_firmware *fw); struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node); #else static inline int rpi_firmware_property(struct rpi_firmware *fw, u32 tag, @@ -154,6 +155,7 @@ static inline int rpi_firmware_property_list(struct rpi_firmware *fw, return -ENOSYS; } +static inline void rpi_firmware_put(struct rpi_firmware *fw) { } static inline struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node) { return NULL;