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authorThomas Pugliese <thomas.pugliese@gmail.com>2013-06-24 23:26:35 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-06-25 03:20:43 +0400
commita899575191ba85a71401f2c8f36bec7b14487043 (patch)
tree74070049b20ec44cf625db68ac62751e4b33cab0 /drivers/uwb
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/uwb')
-rw-r--r--drivers/uwb/pal.c2
-rw-r--r--drivers/uwb/uwb-internal.h3
2 files changed, 4 insertions, 1 deletions
diff --git a/drivers/uwb/pal.c b/drivers/uwb/pal.c
index 8ee7d90a8c68..690577d2a35b 100644
--- a/drivers/uwb/pal.c
+++ b/drivers/uwb/pal.c
@@ -44,10 +44,12 @@ int uwb_pal_register(struct uwb_pal *pal)
int ret;
if (pal->device) {
+ /* create a link to the uwb_rc in the PAL device's directory. */
ret = sysfs_create_link(&pal->device->kobj,
&rc->uwb_dev.dev.kobj, "uwb_rc");
if (ret < 0)
return ret;
+ /* create a link to the PAL in the UWB device's directory. */
ret = sysfs_create_link(&rc->uwb_dev.dev.kobj,
&pal->device->kobj, pal->name);
if (ret < 0) {
diff --git a/drivers/uwb/uwb-internal.h b/drivers/uwb/uwb-internal.h
index a7494bf10081..9a103b100f1e 100644
--- a/drivers/uwb/uwb-internal.h
+++ b/drivers/uwb/uwb-internal.h
@@ -55,7 +55,8 @@ static inline struct uwb_rc *__uwb_rc_get(struct uwb_rc *rc)
static inline void __uwb_rc_put(struct uwb_rc *rc)
{
- uwb_dev_put(&rc->uwb_dev);
+ if (rc)
+ uwb_dev_put(&rc->uwb_dev);
}
extern int uwb_rc_reset(struct uwb_rc *rc);