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usb: roles: Take care of driver module reference counting 

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

Fixes: fde0aa6c17 ("usb: common: Small class for USB role switches")
Cc: <stable@vger.kernel.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Heikki Krogerus 2018-09-19 10:58:05 +03:00 committed by Greg Kroah-Hartman
parent c9a4cb204e
commit 5c54fcac9a
1 changed files with 12 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/usb/common/roles.c
View File

@ -109,8 +109,15 @@ static void *usb_role_switch_match(struct device_connection *con, int ep,
*/
struct usb_role_switch *usb_role_switch_get(struct device *dev)
{
return device_connection_find_match(dev, "usb-role-switch", NULL,
usb_role_switch_match);
struct usb_role_switch *sw;
sw = device_connection_find_match(dev, "usb-role-switch", NULL,
usb_role_switch_match);
if (!IS_ERR_OR_NULL(sw))
WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
return sw;
}
EXPORT_SYMBOL_GPL(usb_role_switch_get);
@ -122,8 +129,10 @@ EXPORT_SYMBOL_GPL(usb_role_switch_get);
*/
void usb_role_switch_put(struct usb_role_switch *sw)
{
if (!IS_ERR_OR_NULL(sw))
if (!IS_ERR_OR_NULL(sw)) {
put_device(&sw->dev);
module_put(sw->dev.parent->driver->owner);
}
}
EXPORT_SYMBOL_GPL(usb_role_switch_put);