coresight: Add try_get_module() in coresight_grab_device() (32b0707a) · Commits · 戴 / test

drivers/hwtracing/coresight/coresight.c

+53 −7

Original line number	Diff line number	Diff line
		@@ -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;
		}
		pm_runtime_get_sync(csdev->dev.parent);
		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);
		}
		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 @@ out:
		* 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);

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