sound: usb: Fix possible race between release and cleanup

In a case where the physical disconnect of headset
and the disable call from QMI race with each other,
there is a possibility that usb_sec_event_ring_cleanup
is called at the same time from uaudio_dev_cleanup
and uaudio_dev_release leading to kernel panic.
Fix this by seriailizing both these calls using
the dev_lock mutex.

Change-Id: I88abccca704786446e0826fc60994c9580828156
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>

sound/usb/usb_audio_qmi_svc.c

@@ -1156,17 +1156,17 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle,
 
 response:
 	if (!req_msg->enable && ret != -EINVAL) {
+		mutex_lock(&chip->dev_lock);
 		if (info_idx >= 0) {
-			mutex_lock(&chip->dev_lock);
 			info = &uadev[pcm_card_num].info[info_idx];
 			uaudio_dev_intf_cleanup(uadev[pcm_card_num].udev, info);
 			uaudio_dbg("release resources: intf# %d card# %d\n",
 					subs->interface, pcm_card_num);
-			mutex_unlock(&chip->dev_lock);
 		}
 		if (atomic_read(&uadev[pcm_card_num].in_use))
 			kref_put(&uadev[pcm_card_num].kref,
 					uaudio_dev_release);
+		mutex_unlock(&chip->dev_lock);
 	}
 
 	resp.usb_token = req_msg->usb_token;