1 files changed, 15 insertions, 6 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 683617714e7c..3e15add665e2 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -360,7 +360,7 @@ static void acm_ctrl_irq(struct urb *urb)
 	}
 exit:
 	retval = usb_submit_urb(urb, GFP_ATOMIC);
-	if (retval)
+	if (retval && retval != -EPERM)
 		dev_err(&acm->control->dev, "%s - usb_submit_urb failed: %d\n",
 							__func__, retval);
 }
@@ -417,25 +417,33 @@ static void acm_read_bulk_callback(struct urb *urb)
 	struct acm_rb *rb = urb->context;
 	struct acm *acm = rb->instance;
 	unsigned long flags;
+	int status = urb->status;
 
 	dev_vdbg(&acm->data->dev, "%s - urb %d, len %d\n", __func__,
 					rb->index, urb->actual_length);
-	set_bit(rb->index, &acm->read_urbs_free);
 
 	if (!acm->dev) {
+		set_bit(rb->index, &acm->read_urbs_free);
 		dev_dbg(&acm->data->dev, "%s - disconnected\n", __func__);
 		return;
 	}
 
-	if (urb->status) {
+	if (status) {
+		set_bit(rb->index, &acm->read_urbs_free);
 		dev_dbg(&acm->data->dev, "%s - non-zero urb status: %d\n",
-							__func__, urb->status);
+							__func__, status);
 		return;
 	}
 
 	usb_mark_last_busy(acm->dev);
 
 	acm_process_read_urb(acm, urb);
+	/*
+	 * Unthrottle may run on another CPU which needs to see events
+	 * in the same order. Submission has an implict barrier
+	 */
+	smp_mb__before_atomic();
+	set_bit(rb->index, &acm->read_urbs_free);
 
 	/* throttle device if requested by tty */
 	spin_lock_irqsave(&acm->read_lock, flags);
@@ -454,13 +462,14 @@ static void acm_write_bulk(struct urb *urb)
 	struct acm_wb *wb = urb->context;
 	struct acm *acm = wb->instance;
 	unsigned long flags;
+	int status = urb->status;
 
-	if (urb->status	|| (urb->actual_length != urb->transfer_buffer_length))
+	if (status || (urb->actual_length != urb->transfer_buffer_length))
 		dev_vdbg(&acm->data->dev, "%s - len %d/%d, status %d\n",
 			__func__,
 			urb->actual_length,
 			urb->transfer_buffer_length,
-			urb->status);
+			status);
 
 	spin_lock_irqsave(&acm->write_lock, flags);
 	acm_write_done(acm, wb);