From mboxrd@z Thu Jan 1 00:00:00 1970 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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 E6C5AC433E1 for ; Fri, 21 Aug 2020 03:47:49 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 A62E220758 for ; Fri, 21 Aug 2020 03:47:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ykwAoa6Q"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="JeRKYVN/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A62E220758 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org 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=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=vA2DE3SYrAwfhPQAIjhiWfaWzujv5/YYt/gDKhw+nS0=; b=ykwAoa6Qx194O6Hi/ckmDPifB AxSJNoV+oOPkMDguUAV0A6LRlrVAue75OMhkyOlJt3SQVNCiFwPemb4SEgxBF3F377uBUJxTg9wSI R/qdqygTKI8KcMUj0jpDgkIQ/2kPHD3YnHw6N+IhKH+r12on2z9O5xD3UKv09I60eytK7+N+cpKbX FRD13Wr8FM5TYp3XaHHimIlYPYAaEXeNjZhmiJ75u0fdbDbkkZ+msTegk+O3262Ak34gwq+bQs5UI VkBgY8I4J8BpBG/nTIZuOxjcVCX5xl2RX9dDnjBy/ufCDbxln+UdDlZEg7pEJMka9W6xWI/FArNa6 ELeYjRYLA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k8y06-00080I-NB; Fri, 21 Aug 2020 03:45:58 +0000 Received: from mail29.static.mailgun.info ([104.130.122.29]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1k8xzy-0007we-Hd for linux-arm-kernel@lists.infradead.org; Fri, 21 Aug 2020 03:45:54 +0000 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1597981552; h=Content-Transfer-Encoding: MIME-Version: References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=0JWnrqYnoICZtBZ5ETAhr8dod5Y3jvxCvvbjFVLwcIw=; b=JeRKYVN/54q2qy3DXK//UPnqCASTeANQJ37PiQ6MPz+9BcrRdOgukNt5GBhvg8tFRmy74Z1B ebcIYMUmxHFCxcquE8iorsf0U0WudKhyGm33Rxv9ALlURSJns3ubFU+iqZ6T42oM4Ttm2iEs j5iUlGaj3WOqM7QTEXLNmrCgGr8= X-Mailgun-Sending-Ip: 104.130.122.29 X-Mailgun-Sid: WyJiYzAxZiIsICJsaW51eC1hcm0ta2VybmVsQGxpc3RzLmluZnJhZGVhZC5vcmciLCAiYmU5ZTRhIl0= Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n03.prod.us-east-1.postgun.com with SMTP id 5f3f436487bb72acbba09136 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Fri, 21 Aug 2020 03:45:40 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 62899C433B2; Fri, 21 Aug 2020 03:45:39 +0000 (UTC) Received: from tingweiz-gv.qualcomm.com (unknown [180.166.53.21]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: tingwei) by smtp.codeaurora.org (Postfix) with ESMTPSA id 9406EC433A0; Fri, 21 Aug 2020 03:45:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 9406EC433A0 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=tingwei@codeaurora.org From: Tingwei Zhang To: Mathieu Poirier , Suzuki K Poulose , Alexander Shishkin , Mike Leach Subject: [PATCH v10 06/24] coresight: add try_get_module() in coresight_grab_device() Date: Fri, 21 Aug 2020 11:44:27 +0800 Message-Id: <20200821034445.967-7-tingwei@codeaurora.org> X-Mailer: git-send-email 2.20.0 In-Reply-To: <20200821034445.967-1-tingwei@codeaurora.org> References: <20200821034445.967-1-tingwei@codeaurora.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200820_234553_062273_65BAD296 X-CRM114-Status: GOOD ( 24.75 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tsoni@codeaurora.org, Sai Prakash Ranjan , Kim Phillips , Mao Jinlong , Greg Kroah-Hartman , coresight@lists.linaro.org, Randy Dunlap , Mian Yousaf Kaukab , Russell King , linux-kernel@vger.kernel.org, Tingwei Zhang , Leo Yan , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When coresight device is in an active session, driver module of that device should not be removed. Use try_get_module() in coresight_grab_device() to prevent module to be unloaded. Use get_device()/put_device() to protect device data in the middle of active session. Signed-off-by: Tingwei Zhang Tested-by: Mike Leach Suggested-by: Suzuki K Poulose --- drivers/hwtracing/coresight/coresight.c | 60 ++++++++++++++++++++++--- 1 file changed, 53 insertions(+), 7 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index cd17aea6b50d..b040d4421f84 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -633,13 +633,45 @@ struct coresight_device *coresight_get_sink_by_id(u32 id) return dev ? to_coresight_device(dev) : NULL; } +/** + * coresight_get_ref- Helper function to increase reference count to module + * and device. + * Return true in successful case and power up the device. + * Return false when failed to get reference of module. + */ +static inline bool coresight_get_ref(struct coresight_device *csdev) +{ + struct device *dev = csdev->dev.parent; + + /* Make sure the driver can't be removed */ + if (!try_module_get(dev->driver->owner)) + return false; + /* Make sure the device can't go away */ + get_device(dev); + pm_runtime_get_sync(dev); + return true; +} + +/** + * coresight_put_ref- Helper function to decrease reference count to module + * and device. Power off the device. + */ +static inline void coresight_put_ref(struct coresight_device *csdev) +{ + struct device *dev = csdev->dev.parent; + + pm_runtime_put(dev); + put_device(dev); + module_put(dev->driver->owner); +} + /* * coresight_grab_device - Power up this device and any of the helper * devices connected to it for trace operation. Since the helper devices * don't appear on the trace path, they should be handled along with the * the master device. */ -static void coresight_grab_device(struct coresight_device *csdev) +static int coresight_grab_device(struct coresight_device *csdev) { int i; @@ -648,9 +680,20 @@ static void coresight_grab_device(struct coresight_device *csdev) child = csdev->pdata->conns[i].child_dev; if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) - pm_runtime_get_sync(child->dev.parent); + if (!coresight_get_ref(child)) + goto err; + } + if (coresight_get_ref(csdev)) + return 0; +err: + for (i--; i >= 0; i--) { + struct coresight_device *child; + + child = csdev->pdata->conns[i].child_dev; + if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) + coresight_put_ref(child); } - pm_runtime_get_sync(csdev->dev.parent); + return -ENODEV; } /* @@ -661,13 +704,13 @@ static void coresight_drop_device(struct coresight_device *csdev) { int i; - pm_runtime_put(csdev->dev.parent); + coresight_put_ref(csdev); for (i = 0; i < csdev->pdata->nr_outport; i++) { struct coresight_device *child; child = csdev->pdata->conns[i].child_dev; if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) - pm_runtime_put(child->dev.parent); + coresight_put_ref(child); } } @@ -686,7 +729,7 @@ static int _coresight_build_path(struct coresight_device *csdev, struct coresight_device *sink, struct list_head *path) { - int i; + int i, ret; bool found = false; struct coresight_node *node; @@ -716,11 +759,14 @@ static int _coresight_build_path(struct coresight_device *csdev, * is tell the PM runtime core we need this element and add a node * for it. */ + ret = coresight_grab_device(csdev); + if (ret) + return ret; + node = kzalloc(sizeof(struct coresight_node), GFP_KERNEL); if (!node) return -ENOMEM; - coresight_grab_device(csdev); node->csdev = csdev; list_add(&node->link, path); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel