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: Tingwei Zhang <tingwei@codeaurora.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Leo Yan <leo.yan@linaro.org>,
Randy Dunlap <rdunlap@infradead.org>,
Russell King <linux@armlinux.org.uk>,
Kim Phillips <kim.phillips@arm.com>,
Mian Yousaf Kaukab <ykaukab@suse.de>,
tsoni@codeaurora.org,
Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
Mao Jinlong <jinlmao@codeaurora.org>,
coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v10 06/24] coresight: add try_get_module() in coresight_grab_device()
Date: Fri, 21 Aug 2020 11:44:27 +0800 [thread overview]
Message-ID: <20200821034445.967-7-tingwei@codeaurora.org> (raw)
In-Reply-To: <20200821034445.967-1-tingwei@codeaurora.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 <tingwei@codeaurora.org>
Tested-by: Mike Leach <mike.leach@linaro.org>
Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
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
next prev parent reply other threads:[~2020-08-21 3:45 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-21 3:44 [PATCH v10 00/24] coresight: allow to build coresight as modules Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 01/24] coresight: cpu_debug: add module name in Kconfig Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 02/24] coresight: cpu_debug: define MODULE_DEVICE_TABLE Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 03/24] coresight: use IS_ENABLED for CONFIGs that may be modules Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 04/24] coresight: add coresight prefix to barrier_pkt Tingwei Zhang
2020-09-10 22:19 ` Mathieu Poirier
2020-09-11 2:39 ` Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 05/24] coresight: export global symbols Tingwei Zhang
2020-08-21 3:44 ` Tingwei Zhang [this message]
2020-08-21 3:44 ` [PATCH v10 07/24] coresight: stm: allow to build coresight-stm as a module Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 08/24] coresight: etm: perf: Fix warning caused by etm_setup_aux failure Tingwei Zhang
2020-09-10 22:28 ` Mathieu Poirier
2020-09-11 2:49 ` Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 09/24] coresight: etm3x: allow etm3x to be built as a module Tingwei Zhang
2020-09-13 13:17 ` Suzuki K Poulose
2020-09-14 2:19 ` Tingwei Zhang
2020-09-14 15:45 ` Mathieu Poirier
2020-09-14 18:11 ` Mathieu Poirier
2020-08-21 3:44 ` [PATCH v10 10/24] coresight: etm4x: allow etm4x " Tingwei Zhang
2020-08-21 9:10 ` Sai Prakash Ranjan
2020-09-13 13:18 ` Suzuki K Poulose
2020-08-21 3:44 ` [PATCH v10 11/24] coresight: etb: allow etb " Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 12/24] coresight: tpiu: allow tpiu " Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 13/24] coresight: tmc: allow tmc " Tingwei Zhang
2020-08-21 9:09 ` Sai Prakash Ranjan
2020-08-21 3:44 ` [PATCH v10 14/24] coresight: allow funnel driver to be built as module Tingwei Zhang
2020-08-21 9:09 ` Sai Prakash Ranjan
2020-09-13 13:20 ` Suzuki K Poulose
2020-09-13 13:24 ` Suzuki K Poulose
2020-09-14 2:17 ` Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 15/24] coresight: allow replicator " Tingwei Zhang
2020-08-21 9:08 ` Sai Prakash Ranjan
2020-09-10 23:00 ` Mathieu Poirier
2020-08-21 3:44 ` [PATCH v10 16/24] coresight: cti: add function to register cti associate ops Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 17/24] coresight: cti: Fix remove sysfs link error Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 18/24] coresight: cti: Fix bug clearing sysfs links on callback Tingwei Zhang
2020-09-10 23:00 ` Mathieu Poirier
2020-08-21 3:44 ` [PATCH v10 19/24] coresight: cti: don't disable ect device if it's not enabled Tingwei Zhang
2020-09-14 18:07 ` Mathieu Poirier
2020-08-21 3:44 ` [PATCH v10 20/24] coresight: cti: increase reference count when enabling cti Tingwei Zhang
2020-09-14 18:08 ` Mathieu Poirier
2020-08-21 3:44 ` [PATCH v10 21/24] coresight: cti: allow cti to be built as a module Tingwei Zhang
2020-09-10 23:03 ` Mathieu Poirier
2020-09-11 2:51 ` Tingwei Zhang
[not found] ` <010101747b1340f9-b0542779-88d7-4193-b53b-5b5bfab5d6a3-000000@us-west-2.amazonses.com>
2020-09-11 17:42 ` Mathieu Poirier
2020-08-21 3:44 ` [PATCH v10 22/24] coresight: tmc-etr: add function to register catu ops Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 23/24] coresight: catu: allow catu drivers to be built as modules Tingwei Zhang
2020-08-21 3:44 ` [PATCH v10 24/24] coresight: allow the coresight core driver to be built as a module Tingwei Zhang
2020-08-21 9:07 ` Sai Prakash Ranjan
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