4 files changed, 31 insertions, 1 deletions

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 71bb5e477dba..d37965867b23 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -890,13 +890,37 @@ static void uvc_function_unbind(struct usb_configuration *c,
 {
 	struct usb_composite_dev *cdev = c->cdev;
 	struct uvc_device *uvc = to_uvc(f);
+	long wait_ret = 1;
 
 	uvcg_info(f, "%s()\n", __func__);
 
+	/* If we know we're connected via v4l2, then there should be a cleanup
+	 * of the device from userspace either via UVC_EVENT_DISCONNECT or
+	 * though the video device removal uevent. Allow some time for the
+	 * application to close out before things get deleted.
+	 */
+	if (uvc->func_connected) {
+		uvcg_dbg(f, "waiting for clean disconnect\n");
+		wait_ret = wait_event_interruptible_timeout(uvc->func_connected_queue,
+				uvc->func_connected == false, msecs_to_jiffies(500));
+		uvcg_dbg(f, "done waiting with ret: %ld\n", wait_ret);
+	}
+
 	device_remove_file(&uvc->vdev.dev, &dev_attr_function_name);
 	video_unregister_device(&uvc->vdev);
 	v4l2_device_unregister(&uvc->v4l2_dev);
 
+	if (uvc->func_connected) {
+		/* Wait for the release to occur to ensure there are no longer any
+		 * pending operations that may cause panics when resources are cleaned
+		 * up.
+		 */
+		uvcg_warn(f, "%s no clean disconnect, wait for release\n", __func__);
+		wait_ret = wait_event_interruptible_timeout(uvc->func_connected_queue,
+				uvc->func_connected == false, msecs_to_jiffies(1000));
+		uvcg_dbg(f, "done waiting for release with ret: %ld\n", wait_ret);
+	}
+
 	usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
 	kfree(uvc->control_buf);
 
@@ -915,6 +939,7 @@ static struct usb_function *uvc_alloc(struct usb_function_instance *fi)
 
 	mutex_init(&uvc->video.mutex);
 	uvc->state = UVC_STATE_DISCONNECTED;
+	init_waitqueue_head(&uvc->func_connected_queue);
 	opts = fi_to_f_uvc_opts(fi);
 
 	mutex_lock(&opts->lock);
diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h
index c3607a32b986..886103a1fe9b 100644
--- a/drivers/usb/gadget/function/uvc.h
+++ b/drivers/usb/gadget/function/uvc.h
@@ -14,6 +14,7 @@
 #include <linux/spinlock.h>
 #include <linux/usb/composite.h>
 #include <linux/videodev2.h>
+#include <linux/wait.h>
 
 #include <media/v4l2-device.h>
 #include <media/v4l2-dev.h>
@@ -129,6 +130,7 @@ struct uvc_device {
 	struct usb_function func;
 	struct uvc_video video;
 	bool func_connected;
+	wait_queue_head_t func_connected_queue;
 
 	/* Descriptors */
 	struct {
diff --git a/drivers/usb/gadget/function/uvc_queue.c b/drivers/usb/gadget/function/uvc_queue.c
index d852ac9e47e7..2cda982f3765 100644
--- a/drivers/usb/gadget/function/uvc_queue.c
+++ b/drivers/usb/gadget/function/uvc_queue.c
@@ -264,6 +264,8 @@ void uvcg_queue_cancel(struct uvc_video_queue *queue, int disconnect)
 		buf->state = UVC_BUF_STATE_ERROR;
 		vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_ERROR);
 	}
+	queue->buf_used = 0;
+
 	/* This must be protected by the irqlock spinlock to avoid race
 	 * conditions between uvc_queue_buffer and the disconnection event that
 	 * could result in an interruptible wait in uvc_dequeue_buffer. Do not
diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
index a2c78690c5c2..fd8f73bb726d 100644
--- a/drivers/usb/gadget/function/uvc_v4l2.c
+++ b/drivers/usb/gadget/function/uvc_v4l2.c
@@ -253,10 +253,11 @@ uvc_v4l2_subscribe_event(struct v4l2_fh *fh,
 
 static void uvc_v4l2_disable(struct uvc_device *uvc)
 {
-	uvc->func_connected = false;
 	uvc_function_disconnect(uvc);
 	uvcg_video_enable(&uvc->video, 0);
 	uvcg_free_buffers(&uvc->video.queue);
+	uvc->func_connected = false;
+	wake_up_interruptible(&uvc->func_connected_queue);
 }
 
 static int