Commit 3e3b8196 authored by Heikki Krogerus's avatar Heikki Krogerus Committed by Greg Kroah-Hartman
Browse files

usb: typec: mux: Take care of driver module reference counting 



Functions typec_mux_get() and typec_switch_get() already
make sure that the mux device reference count is
incremented, but the same must be done to the driver module
as well to prevent the drivers from being unloaded in the
middle of operation.

This fixes a potential "BUG: unable to handle kernel paging
request at ..." from happening.

Fixes: 93dd2112 ("usb: typec: mux: Get the mux identifier from function parameter")
Acked-by: default avatarHans de Goede <hdegoede@redhat.com>
Tested-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 16c4cb19

drivers/usb/typec/mux.c

+13 −4
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 


#include <linux/device.h>

#include <linux/list.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/usb/typec_mux.h>
@@ -49,8 +50,10 @@ struct typec_switch *typec_switch_get(struct device *dev) 
	mutex_lock(&switch_lock);

	sw = device_connection_find_match(dev, "typec-switch", NULL,

					  typec_switch_match);

	if (!IS_ERR_OR_NULL(sw))

	if (!IS_ERR_OR_NULL(sw)) {

		WARN_ON(!try_module_get(sw->dev->driver->owner));

		get_device(sw->dev);

	}

	mutex_unlock(&switch_lock);



	return sw;
@@ -65,9 +68,11 @@ EXPORT_SYMBOL_GPL(typec_switch_get); 
 */

void typec_switch_put(struct typec_switch *sw)

{

	if (!IS_ERR_OR_NULL(sw))

	if (!IS_ERR_OR_NULL(sw)) {

		module_put(sw->dev->driver->owner);

		put_device(sw->dev);

	}

}

EXPORT_SYMBOL_GPL(typec_switch_put);



/**
@@ -136,8 +141,10 @@ struct typec_mux *typec_mux_get(struct device *dev, const char *name) 


	mutex_lock(&mux_lock);

	mux = device_connection_find_match(dev, name, NULL, typec_mux_match);

	if (!IS_ERR_OR_NULL(mux))

	if (!IS_ERR_OR_NULL(mux)) {

		WARN_ON(!try_module_get(mux->dev->driver->owner));

		get_device(mux->dev);

	}

	mutex_unlock(&mux_lock);



	return mux;
@@ -152,9 +159,11 @@ EXPORT_SYMBOL_GPL(typec_mux_get); 
 */

void typec_mux_put(struct typec_mux *mux)

{

	if (!IS_ERR_OR_NULL(mux))

	if (!IS_ERR_OR_NULL(mux)) {

		module_put(mux->dev->driver->owner);

		put_device(mux->dev);

	}

}

EXPORT_SYMBOL_GPL(typec_mux_put);



/**

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