[PATCH v2 19/20] coresight: add try_get_module() in coresight_grab_device()
Tingwei Zhang
tingwei at codeaurora.org
Tue Jul 14 01:49:13 EDT 2020
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.
Signed-off-by: Tingwei Zhang <tingwei at codeaurora.org>
---
drivers/hwtracing/coresight/coresight.c | 27 +++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index cf7079f4b99c..ca4fd0001603 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -655,7 +655,7 @@ struct coresight_device *coresight_get_sink_by_id(u32 id)
* 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;
@@ -663,10 +663,25 @@ static void coresight_grab_device(struct coresight_device *csdev)
struct coresight_device *child;
child = csdev->pdata->conns[i].child_dev;
- if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
+ if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) {
+ if (!try_module_get(child->dev.parent->driver->owner))
+ goto err;
pm_runtime_get_sync(child->dev.parent);
+ }
}
+ if (!try_module_get(csdev->dev.parent->driver->owner))
+ goto err;
pm_runtime_get_sync(csdev->dev.parent);
+ 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)
+ pm_runtime_put(child->dev.parent);
+ }
+ return -ENODEV;
}
/*
@@ -678,12 +693,15 @@ static void coresight_drop_device(struct coresight_device *csdev)
int i;
pm_runtime_put(csdev->dev.parent);
+ module_put(csdev->dev.parent->driver->owner);
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)
+ if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) {
pm_runtime_put(child->dev.parent);
+ module_put(child->dev.parent->driver->owner);
+ }
}
}
@@ -736,7 +754,8 @@ static int _coresight_build_path(struct coresight_device *csdev,
if (!node)
return -ENOMEM;
- coresight_grab_device(csdev);
+ if (coresight_grab_device(csdev))
+ return -ENODEV;
node->csdev = csdev;
list_add(&node->link, path);
--
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