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From: Tingwei Zhang <tingwei@codeaurora.org>
To: Mathieu Poirier <mathieu.poirier@linaro.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Mike Leach <mike.leach@linaro.org>
Cc: tsoni@codeaurora.org,
	Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
	Kim Phillips <kim.phillips@arm.com>,
	Mao Jinlong <jinlmao@codeaurora.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	coresight@lists.linaro.org, Randy Dunlap <rdunlap@infradead.org>,
	Mian Yousaf Kaukab <ykaukab@suse.de>,
	Russell King <linux@armlinux.org.uk>,
	linux-kernel@vger.kernel.org,
	Tingwei Zhang <tingwei@codeaurora.org>,
	Leo Yan <leo.yan@linaro.org>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v9 20/24] coresight: cti: increase reference count when enabling cti
Date: Thu, 20 Aug 2020 13:47:14 +0800	[thread overview]
Message-ID: <20200820054718.20115-21-tingwei@codeaurora.org> (raw)
In-Reply-To: <20200820054718.20115-1-tingwei@codeaurora.org>

CTI device is enabled when associated coresight device is enabled.
Increase the module and device reference count for CTI device
when it's enabled. This can prevent CTI device be removed or
module be unloaded when CTI device is enabled by an active trace
session.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
---
 drivers/hwtracing/coresight/coresight.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index d354fd57474e..6c9f6930b8b8 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -241,19 +241,30 @@ coresight_control_assoc_ectdev(struct coresight_device *csdev, bool enable)
 {
 	int ect_ret = 0;
 	struct coresight_device *ect_csdev = csdev->ect_dev;
+	struct module *mod;
 
 	if (!ect_csdev)
 		return 0;
 	if ((!ect_ops(ect_csdev)->enable) || (!ect_ops(ect_csdev)->disable))
 		return 0;
 
+	mod = ect_csdev->dev.parent->driver->owner;
 	if (enable) {
-		ect_ret = ect_ops(ect_csdev)->enable(ect_csdev);
-		if (!ect_ret)
-			csdev->ect_enabled = true;
+		if (try_module_get(mod)) {
+			ect_ret = ect_ops(ect_csdev)->enable(ect_csdev);
+			if (ect_ret) {
+				module_put(mod);
+			} else {
+				get_device(ect_csdev->dev.parent);
+				csdev->ect_enabled = true;
+			}
+		} else
+			ect_ret = -ENODEV;
 	} else {
 		if (csdev->ect_enabled) {
 			ect_ret = ect_ops(ect_csdev)->disable(ect_csdev);
+			put_device(ect_csdev->dev.parent);
+			module_put(mod);
 			csdev->ect_enabled = false;
 		}
 	}
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


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  parent reply	other threads:[~2020-08-20  5:55 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-20  5:46 [PATCH v9 00/24] coresight: allow to build coresight as modules Tingwei Zhang
2020-08-20  5:46 ` [PATCH v9 01/24] coresight: cpu_debug: add module name in Kconfig Tingwei Zhang
2020-08-20  5:46 ` [PATCH v9 02/24] coresight: cpu_debug: define MODULE_DEVICE_TABLE Tingwei Zhang
2020-08-20  5:46 ` [PATCH v9 03/24] coresight: use IS_ENABLED for CONFIGs that may be modules Tingwei Zhang
2020-08-20  5:46 ` [PATCH v9 04/24] coresight: add coresight prefix to barrier_pkt Tingwei Zhang
2020-08-20  5:46 ` [PATCH v9 05/24] coresight: export global symbols Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 06/24] coresight: add try_get_module() in coresight_grab_device() Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 07/24] coresight: stm: allow to build coresight-stm as a module Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 08/24] coresight: etm: perf: Fix warning caused by etm_setup_aux failure Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 09/24] coresight: etm3x: allow etm3x to be built as a module Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 10/24] coresight: etm4x: allow etm4x " Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 11/24] coresight: etb: allow etb " Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 12/24] coresight: tpiu: allow tpiu " Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 13/24] coresight: tmc: allow tmc " Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 14/24] coresight: allow funnel driver to be built as module Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 15/24] coresight: allow replicator " Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 16/24] coresight: cti: add function to register cti associate ops Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 17/24] coresight: cti: Fix remove sysfs link error Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 18/24] coresight: cti: Fix bug clearing sysfs links on callback Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 19/24] coresight: cti: don't disable ect device if it's not enabled Tingwei Zhang
2020-08-20  5:47 ` Tingwei Zhang [this message]
2020-08-20  5:47 ` [PATCH v9 21/24] coresight: cti: allow cti to be built as a module Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 22/24] coresight: tmc-etr: add function to register catu ops Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 23/24] coresight: catu: allow catu drivers to be built as modules Tingwei Zhang
2020-08-20  5:47 ` [PATCH v9 24/24] coresight: allow the coresight core driver to be built as a module Tingwei Zhang
2020-09-08 17:53 ` [PATCH v9 00/24] coresight: allow to build coresight as modules Mathieu Poirier
2020-09-09  2:54   ` Tingwei Zhang
     [not found]   ` <0101017470c9475d-00e296fc-1173-4afa-95cb-22ac70d85d5b-000000@us-west-2.amazonses.com>
2020-09-09 16:15     ` Mathieu Poirier
2020-09-09 20:45       ` tsoni
     [not found]       ` <c8737d9935a1b7a7372c41492939648d@codeaurora.org>
2020-09-09 23:56         ` Tingwei Zhang

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