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| author | Thomas Pugliese <thomas.pugliese@gmail.com> | 2013-06-24 14:26:35 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-06-24 16:20:43 -0700 |
| commit | a899575191ba85a71401f2c8f36bec7b14487043 (patch) | |
| tree | 74070049b20ec44cf625db68ac62751e4b33cab0 /drivers/uwb | |
| parent | 6e6581e0a94758a4e69fab82407d39312eeff5c4 (diff) | |
| download | linux-a899575191ba85a71401f2c8f36bec7b14487043.tar.gz linux-a899575191ba85a71401f2c8f36bec7b14487043.tar.bz2 linux-a899575191ba85a71401f2c8f36bec7b14487043.zip | |
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.c | 2 | ||||
| -rw-r--r-- | drivers/uwb/uwb-internal.h | 3 |
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); |