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authorThomas Pugliese <thomas.pugliese@gmail.com>2013-06-24 19:26:35 (GMT)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-06-24 23:20:43 (GMT)
commita899575191ba85a71401f2c8f36bec7b14487043 (patch)
tree74070049b20ec44cf625db68ac62751e4b33cab0 /drivers/usb
parent6e6581e0a94758a4e69fab82407d39312eeff5c4 (diff)
downloadlinux-a899575191ba85a71401f2c8f36bec7b14487043.tar.xz
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: Thomas Pugliese <thomas.pugliese@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/host/hwa-hc.c11
-rw-r--r--drivers/usb/wusbcore/mmc.c27
-rw-r--r--drivers/usb/wusbcore/pal.c5
-rw-r--r--drivers/usb/wusbcore/reservation.c3
-rw-r--r--drivers/usb/wusbcore/wusbhc.c9
5 files changed, 38 insertions, 17 deletions
diff --git a/drivers/usb/host/hwa-hc.c b/drivers/usb/host/hwa-hc.c
index 4af750e..483990c 100644
--- a/drivers/usb/host/hwa-hc.c
+++ b/drivers/usb/host/hwa-hc.c
@@ -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;
diff --git a/drivers/usb/wusbcore/mmc.c b/drivers/usb/wusbcore/mmc.c
index 021467f..b71760c 100644
--- a/drivers/usb/wusbcore/mmc.c
+++ b/drivers/usb/wusbcore/mmc.c
@@ -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);
diff --git a/drivers/usb/wusbcore/pal.c b/drivers/usb/wusbcore/pal.c
index d0b172c..59e100c 100644
--- a/drivers/usb/wusbcore/pal.c
+++ b/drivers/usb/wusbcore/pal.c
@@ -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)
{
- uwb_pal_unregister(&wusbhc->pal);
+ if (wusbhc->uwb_rc)
+ uwb_pal_unregister(&wusbhc->pal);
}
diff --git a/drivers/usb/wusbcore/reservation.c b/drivers/usb/wusbcore/reservation.c
index 6f4fafd..ead79f7 100644
--- a/drivers/usb/wusbcore/reservation.c
+++ b/drivers/usb/wusbcore/reservation.c
@@ -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;
diff --git a/drivers/usb/wusbcore/wusbhc.c b/drivers/usb/wusbcore/wusbhc.c
index e712af3..742c607 100644
--- a/drivers/usb/wusbcore/wusbhc.c
+++ b/drivers/usb/wusbcore/wusbhc.c
@@ -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;
}
@@ -457,7 +451,8 @@ EXPORT_SYMBOL_GPL(wusbhc_giveback_urb);
*/
void wusbhc_reset_all(struct wusbhc *wusbhc)
{
- uwb_rc_reset_all(wusbhc->uwb_rc);
+ if (wusbhc->uwb_rc)
+ uwb_rc_reset_all(wusbhc->uwb_rc);
}
EXPORT_SYMBOL_GPL(wusbhc_reset_all);