On 06/05/2018 10:07 PM, Kim Phillips wrote:
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 <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Russell King <[email protected]>
Signed-off-by: Kim Phillips <[email protected]>
---
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;
+ }
+
Kim,
It would be safer to do the check before we actually add the device to
the path above. That way, we don't add an unavailable device to the
path, which will be "released" in the release_path below.
Otherwise looks good to me.
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);
}
Suzuki
