Commit a8995751 authored by Thomas Pugliese's avatar Thomas Pugliese Committed by Greg Kroah-Hartman
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USB: HWA: fix device probe failure 



This patch fixes a race condition that caused the HWA_HC interface probe
function to occasionally fail.  The HWA_HC would attempt to register
itself with the HWA_RC by searching for a uwb_rc class device with the
same parent device ptr.  If the probe function for the HWA_RC interface
had yet to run, the uwb_rc class device would not have been created
causing the look up to fail and the HWA_HC probe function to return an
error causing the device to be unusable.

The fix is for the HWA to delay registering with the HWA_RC until
receiving the command from userspace to start the wireless channel.  It
is the responsibility of userspace to ensure that the uwb_rc class
device has been created before starting the HWA channel.

Signed-off-by: default avatarThomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6e6581e0

drivers/usb/host/hwa-hc.c

+3 −8
Original line number Diff line number Diff line
@@ -683,12 +683,9 @@ static int hwahc_create(struct hwahc *hwahc, struct usb_interface *iface) 
	wa->usb_dev = usb_get_dev(usb_dev);	/* bind the USB device */

	wa->usb_iface = usb_get_intf(iface);

	wusbhc->dev = dev;

	wusbhc->uwb_rc = uwb_rc_get_by_grandpa(iface->dev.parent);

	if (wusbhc->uwb_rc == NULL) {

		result = -ENODEV;

		dev_err(dev, "Cannot get associated UWB Host Controller\n");

		goto error_rc_get;

	}

	/* defer getting the uwb_rc handle until it is needed since it

	 * may not have been registered by the hwa_rc driver yet. */

	wusbhc->uwb_rc = NULL;

	result = wa_fill_descr(wa);	/* Get the device descriptor */

	if (result < 0)

		goto error_fill_descriptor;
@@ -731,8 +728,6 @@ error_wusbhc_create: 
	/* WA Descr fill allocs no resources */

error_security_create:

error_fill_descriptor:

	uwb_rc_put(wusbhc->uwb_rc);

error_rc_get:

	usb_put_intf(iface);

	usb_put_dev(usb_dev);

	return result;

drivers/usb/wusbcore/mmc.c

+27 −0
Original line number Diff line number Diff line
@@ -195,6 +195,7 @@ int wusbhc_start(struct wusbhc *wusbhc) 
	struct device *dev = wusbhc->dev;



	WARN_ON(wusbhc->wuie_host_info != NULL);

	BUG_ON(wusbhc->uwb_rc == NULL);



	result = wusbhc_rsv_establish(wusbhc);

	if (result < 0) {
@@ -276,12 +277,38 @@ int wusbhc_chid_set(struct wusbhc *wusbhc, const struct wusb_ckhdid *chid) 
		}

		wusbhc->chid = *chid;

	}



	/* register with UWB if we haven't already since we are about to start

	    the radio. */

	if ((chid) && (wusbhc->uwb_rc == NULL)) {

		wusbhc->uwb_rc = uwb_rc_get_by_grandpa(wusbhc->dev->parent);

		if (wusbhc->uwb_rc == NULL) {

			result = -ENODEV;

			dev_err(wusbhc->dev, "Cannot get associated UWB Host Controller\n");

			goto error_rc_get;

		}



		result = wusbhc_pal_register(wusbhc);

		if (result < 0) {

			dev_err(wusbhc->dev, "Cannot register as a UWB PAL\n");

			goto error_pal_register;

		}

	}

	mutex_unlock(&wusbhc->mutex);



	if (chid)

		result = uwb_radio_start(&wusbhc->pal);

	else

		uwb_radio_stop(&wusbhc->pal);



	return result;



error_pal_register:

	uwb_rc_put(wusbhc->uwb_rc);

	wusbhc->uwb_rc = NULL;

error_rc_get:

	mutex_unlock(&wusbhc->mutex);



	return result;

}

EXPORT_SYMBOL_GPL(wusbhc_chid_set);

drivers/usb/wusbcore/pal.c

+3 −2
Original line number Diff line number Diff line
@@ -45,10 +45,11 @@ int wusbhc_pal_register(struct wusbhc *wusbhc) 
}



/**

 * wusbhc_pal_register - unregister the WUSB HC as a UWB PAL

 * wusbhc_pal_unregister - unregister the WUSB HC as a UWB PAL

 * @wusbhc: the WUSB HC

 */

void wusbhc_pal_unregister(struct wusbhc *wusbhc)

{

	if (wusbhc->uwb_rc)

		uwb_pal_unregister(&wusbhc->pal);

}

drivers/usb/wusbcore/reservation.c

+3 −0
Original line number Diff line number Diff line
@@ -80,6 +80,9 @@ int wusbhc_rsv_establish(struct wusbhc *wusbhc) 
	struct uwb_dev_addr bcid;

	int ret;



	if (rc == NULL)

		return -ENODEV;



	rsv = uwb_rsv_create(rc, wusbhc_rsv_complete_cb, wusbhc);

	if (rsv == NULL)

		return -ENOMEM;

drivers/usb/wusbcore/wusbhc.c

+2 −7
Original line number Diff line number Diff line
@@ -325,13 +325,7 @@ int wusbhc_b_create(struct wusbhc *wusbhc) 
		goto error_create_attr_group;

	}



	result = wusbhc_pal_register(wusbhc);

	if (result < 0)

		goto error_pal_register;

	return 0;



error_pal_register:

	sysfs_remove_group(wusbhc_kobj(wusbhc), &wusbhc_attr_group);

error_create_attr_group:

	return result;

}
@@ -457,6 +451,7 @@ EXPORT_SYMBOL_GPL(wusbhc_giveback_urb); 
 */

void wusbhc_reset_all(struct wusbhc *wusbhc)

{

	if (wusbhc->uwb_rc)

		uwb_rc_reset_all(wusbhc->uwb_rc);

}

EXPORT_SYMBOL_GPL(wusbhc_reset_all);

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