Commit b433c4c7 authored by Heikki Krogerus's avatar Heikki Krogerus Committed by Greg Kroah-Hartman
Browse files

usb: Iterator for ports 



Introducing usb_for_each_port(). It works the same way as
usb_for_each_dev(), but instead of going through every USB
device in the system, it walks through the USB ports in the
system.

Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20210407065555.88110-4-heikki.krogerus@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 63cd7861

drivers/usb/core/usb.c

+46 −0
Original line number Diff line number Diff line
@@ -398,6 +398,52 @@ int usb_for_each_dev(void *data, int (*fn)(struct usb_device *, void *)) 
}

EXPORT_SYMBOL_GPL(usb_for_each_dev);



struct each_hub_arg {

	void *data;

	int (*fn)(struct device *, void *);

};



static int __each_hub(struct usb_device *hdev, void *data)

{

	struct each_hub_arg *arg = (struct each_hub_arg *)data;

	struct usb_hub *hub;

	int ret = 0;

	int i;



	hub = usb_hub_to_struct_hub(hdev);

	if (!hub)

		return 0;



	mutex_lock(&usb_port_peer_mutex);



	for (i = 0; i < hdev->maxchild; i++) {

		ret = arg->fn(&hub->ports[i]->dev, arg->data);

		if (ret)

			break;

	}



	mutex_unlock(&usb_port_peer_mutex);



	return ret;

}



/**

 * usb_for_each_port - interate over all USB ports in the system

 * @data: data pointer that will be handed to the callback function

 * @fn: callback function to be called for each USB port

 *

 * Iterate over all USB ports and call @fn for each, passing it @data. If it

 * returns anything other than 0, we break the iteration prematurely and return

 * that value.

 */

int usb_for_each_port(void *data, int (*fn)(struct device *, void *))

{

	struct each_hub_arg arg = {data, fn};



	return usb_for_each_dev(&arg, __each_hub);

}

EXPORT_SYMBOL_GPL(usb_for_each_port);



/**

 * usb_release_dev - free a usb device structure when all users of it are finished.

 * @dev: device that's been disconnected

include/linux/usb.h

+9 −0
Original line number Diff line number Diff line
@@ -882,6 +882,15 @@ extern struct usb_host_interface *usb_find_alt_setting( 
		unsigned int iface_num,

		unsigned int alt_num);



#if IS_REACHABLE(CONFIG_USB)

int usb_for_each_port(void *data, int (*fn)(struct device *, void *));

#else

static inline int usb_for_each_port(void *data, int (*fn)(struct device *, void *))

{

	return 0;

}

#endif



/* port claiming functions */

int usb_hub_claim_port(struct usb_device *hdev, unsigned port1,

		struct usb_dev_state *owner);