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Commit 57480484 authored by Jon Medhurst (Tixy)'s avatar Jon Medhurst (Tixy) Committed by Russell King
Browse files

component: Detach components when deleting master struct 



component_master_add_with_match calls find_components which, if any
components already exist, it attaches to the master struct. However, if
we later encounter an error the master struct is deleted, leaving
components with a dangling pointer to it.

If the error was a temporary one, e.g. for probe deferral, then when
the master device is re-probed, it will fail to find the required
components as they appear to already be attached to a master.

Fix this by nulling components pointers to the master struct when it is
deleted. This code is factored out into a separate function so it can be
shared with component_master_del.

Signed-off-by: default avatarJon Medhurst <tixy@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 9a4e7849

drivers/base/component.c

+22 −19
Original line number Diff line number Diff line
@@ -285,6 +285,24 @@ void component_match_add_release(struct device *master, 
}

EXPORT_SYMBOL(component_match_add_release);



static void free_master(struct master *master)

{

	struct component_match *match = master->match;

	int i;



	list_del(&master->node);



	if (match) {

		for (i = 0; i < match->num; i++) {

			struct component *c = match->compare[i].component;

			if (c)

				c->master = NULL;

		}

	}



	kfree(master);

}



int component_master_add_with_match(struct device *dev,

	const struct component_master_ops *ops,

	struct component_match *match)
@@ -311,11 +329,9 @@ int component_master_add_with_match(struct device *dev, 


	ret = try_to_bring_up_master(master, NULL);



	if (ret < 0) {

		/* Delete off the list if we weren't successful */

		list_del(&master->node);

		kfree(master);

	}

	if (ret < 0)

		free_master(master);



	mutex_unlock(&component_mutex);



	return ret < 0 ? ret : 0;
@@ -326,25 +342,12 @@ void component_master_del(struct device *dev, 
	const struct component_master_ops *ops)

{

	struct master *master;

	int i;



	mutex_lock(&component_mutex);

	master = __master_find(dev, ops);

	if (master) {

		struct component_match *match = master->match;



		take_down_master(master);



		list_del(&master->node);



		if (match) {

			for (i = 0; i < match->num; i++) {

				struct component *c = match->compare[i].component;

				if (c)

					c->master = NULL;

			}

		}

		kfree(master);

		free_master(master);

	}

	mutex_unlock(&component_mutex);

}