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 v11 06/24] coresight: add try_get_module() in coresight_grab_device()
Date: Tue, 15 Sep 2020 18:40:58 +0800 [thread overview]
Message-ID: <20200915104116.16789-7-tingwei@codeaurora.org> (raw)
In-Reply-To: <20200915104116.16789-1-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 d1aea3a1e7b6..4faa4aa3964d 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -629,13 +629,45 @@ 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;
@@ -644,9 +676,20 @@ 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;
}
/*
@@ -657,13 +700,13 @@ 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);
}
}
@@ -682,7 +725,7 @@ 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;
@@ -712,11 +755,14 @@ 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
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next prev parent reply other threads:[~2020-09-15 10:47 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-15 10:40 [PATCH v11 00/24] coresight: allow to build coresight as modules Tingwei Zhang
2020-09-15 10:40 ` [PATCH v11 01/24] coresight: cpu_debug: add module name in Kconfig Tingwei Zhang
2020-09-15 10:40 ` [PATCH v11 02/24] coresight: cpu_debug: define MODULE_DEVICE_TABLE Tingwei Zhang
2020-09-15 10:40 ` [PATCH v11 03/24] coresight: use IS_ENABLED for CONFIGs that may be modules Tingwei Zhang
2020-09-15 10:40 ` [PATCH v11 04/24] coresight: add coresight prefix to barrier_pkt Tingwei Zhang
2020-09-15 10:40 ` [PATCH v11 05/24] coresight: export global symbols Tingwei Zhang
2020-09-15 10:40 ` Tingwei Zhang [this message]
2020-09-15 11:08 ` [PATCH v11 06/24] coresight: add try_get_module() in coresight_grab_device() Suzuki K Poulose
2020-09-15 10:40 ` [PATCH v11 07/24] coresight: stm: allow to build coresight-stm as a module Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 08/24] coresight: etm: perf: Fix warning caused by etm_setup_aux failure Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 09/24] coresight: etm3x: allow etm3x to be built as a module Tingwei Zhang
2020-09-15 18:09 ` Mathieu Poirier
2020-09-22 21:42 ` Mathieu Poirier
2020-09-23 0:23 ` Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 10/24] coresight: etm4x: allow etm4x " Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 11/24] coresight: etb: allow etb " Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 12/24] coresight: tpiu: allow tpiu " Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 13/24] coresight: tmc: allow tmc " Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 14/24] coresight: allow funnel driver to be built as module Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 15/24] coresight: allow replicator " Tingwei Zhang
2020-09-15 11:25 ` Suzuki K Poulose
2020-09-15 10:41 ` [PATCH v11 16/24] coresight: cti: add function to register cti associate ops Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 17/24] coresight: cti: Fix remove sysfs link error Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 18/24] coresight: cti: Fix bug clearing sysfs links on callback Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 19/24] coresight: cti: don't disable ect device if it's not enabled Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 20/24] coresight: cti: increase reference count when enabling cti Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 21/24] coresight: cti: allow cti to be built as a module Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 22/24] coresight: tmc-etr: add function to register catu ops Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 23/24] coresight: catu: allow catu drivers to be built as modules Tingwei Zhang
2020-09-15 10:41 ` [PATCH v11 24/24] coresight: allow the coresight core driver to be built as a module Tingwei Zhang
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