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Subject[PATCH v4 05/14] coresight: get/put module in coresight_build/release_path
Date
Increment the refcnt for driver modules in current use by calling
module_get in coresight_build_path and module_put in release_path.

This prevents driver modules from being unloaded when they are in use,
either in sysfs or perf mode.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Kim Phillips <kim.phillips@arm.com>
---
drivers/hwtracing/coresight/coresight.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 338f1719641c..1c941351f1d1 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -465,6 +465,12 @@ static int _coresight_build_path(struct coresight_device *csdev,

node->csdev = csdev;
list_add(&node->link, path);
+
+ if (!try_module_get(csdev->dev.parent->driver->owner)) {
+ dev_err(&csdev->dev, "could not get coresight driver module\n");
+ return -ENODEV;
+ }
+
pm_runtime_get_sync(csdev->dev.parent);

return 0;
@@ -510,6 +516,9 @@ void coresight_release_path(struct list_head *path)
csdev = nd->csdev;

pm_runtime_put_sync(csdev->dev.parent);
+
+ module_put(csdev->dev.parent->driver->owner);
+
list_del(&nd->link);
kfree(nd);
}
--
2.17.0
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