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Sat, 25 Jul 2020 09:56:17 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id B2D64C43395; Sat, 25 Jul 2020 09:56:15 +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 5C36AC433A1; Sat, 25 Jul 2020 09:56:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 5C36AC433A1 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 v5 06/22] coresight: add try_get_module() in coresight_grab_device() Date: Sat, 25 Jul 2020 17:55:14 +0800 Message-Id: <20200725095530.18053-7-tingwei@codeaurora.org> X-Mailer: git-send-email 2.20.0 In-Reply-To: <20200725095530.18053-1-tingwei@codeaurora.org> References: <20200725095530.18053-1-tingwei@codeaurora.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200725_055617_879629_968E60CF X-CRM114-Status: GOOD ( 17.93 ) 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 , 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 --- drivers/hwtracing/coresight/coresight.c | 39 +++++++++++++++++++++---- 1 file changed, 34 insertions(+), 5 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index b7151c5f81b1..1626bc885dfe 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -640,7 +640,7 @@ struct coresight_device *coresight_get_sink_by_id(u32 id) * 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; @@ -648,10 +648,30 @@ static void coresight_grab_device(struct coresight_device *csdev) struct coresight_device *child; child = csdev->pdata->conns[i].child_dev; - if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) + if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) { + if (!try_module_get(child->dev.parent->driver->owner)) + goto err; + get_device(child->dev.parent); pm_runtime_get_sync(child->dev.parent); + } } + if (!try_module_get(csdev->dev.parent->driver->owner)) + goto err; + get_device(csdev->dev.parent); pm_runtime_get_sync(csdev->dev.parent); + 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) { + pm_runtime_put(child->dev.parent); + put_device(child->dev.parent); + module_put(child->dev.parent->driver->owner); + } + } + return -ENODEV; } /* @@ -663,12 +683,17 @@ static void coresight_drop_device(struct coresight_device *csdev) int i; pm_runtime_put(csdev->dev.parent); + put_device(csdev->dev.parent); + module_put(csdev->dev.parent->driver->owner); 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) + if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) { pm_runtime_put(child->dev.parent); + put_device(child->dev.parent); + module_put(child->dev.parent->driver->owner); + } } } @@ -687,7 +712,7 @@ 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; @@ -721,7 +746,11 @@ static int _coresight_build_path(struct coresight_device *csdev, if (!node) return -ENOMEM; - coresight_grab_device(csdev); + ret = coresight_grab_device(csdev); + if (ret) { + kfree(node); + return ret; + } 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