1 files changed, 54 insertions, 21 deletions

diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c
index b74e98e94393..d719c16ea30b 100644
--- a/drivers/usb/host/xhci-dbgtty.c
+++ b/drivers/usb/host/xhci-dbgtty.c
@@ -25,16 +25,26 @@ static inline struct dbc_port *dbc_to_port(struct xhci_dbc *dbc)
 }
 
 static unsigned int
-dbc_send_packet(struct dbc_port *port, char *packet, unsigned int size)
+dbc_kfifo_to_req(struct dbc_port *port, char *packet)
 {
-	unsigned int		len;
-
-	len = kfifo_len(&port->write_fifo);
-	if (len < size)
-		size = len;
-	if (size != 0)
-		size = kfifo_out(&port->write_fifo, packet, size);
-	return size;
+	unsigned int	len;
+
+	len = kfifo_len(&port->port.xmit_fifo);
+
+	if (len == 0)
+		return 0;
+
+	len = min(len, DBC_MAX_PACKET);
+
+	if (port->tx_boundary)
+		len = min(port->tx_boundary, len);
+
+	len = kfifo_out(&port->port.xmit_fifo, packet, len);
+
+	if (port->tx_boundary)
+		port->tx_boundary -= len;
+
+	return len;
 }
 
 static int dbc_start_tx(struct dbc_port *port)
@@ -49,7 +59,7 @@ static int dbc_start_tx(struct dbc_port *port)
 
 	while (!list_empty(pool)) {
 		req = list_entry(pool->next, struct dbc_request, list_pool);
-		len = dbc_send_packet(port, req->buf, DBC_MAX_PACKET);
+		len = dbc_kfifo_to_req(port, req->buf);
 		if (len == 0)
 			break;
 		do_tty_wake = true;
@@ -213,14 +223,32 @@ static ssize_t dbc_tty_write(struct tty_struct *tty, const u8 *buf,
 {
 	struct dbc_port		*port = tty->driver_data;
 	unsigned long		flags;
+	unsigned int		written = 0;
 
 	spin_lock_irqsave(&port->port_lock, flags);
-	if (count)
-		count = kfifo_in(&port->write_fifo, buf, count);
-	dbc_start_tx(port);
+
+	/*
+	 * Treat tty write as one usb transfer. Make sure the writes are turned
+	 * into TRB request having the same size boundaries as the tty writes.
+	 * Don't add data to kfifo before previous write is turned into TRBs
+	 */
+	if (port->tx_boundary) {
+		spin_unlock_irqrestore(&port->port_lock, flags);
+		return 0;
+	}
+
+	if (count) {
+		written = kfifo_in(&port->port.xmit_fifo, buf, count);
+
+		if (written == count)
+			port->tx_boundary = kfifo_len(&port->port.xmit_fifo);
+
+		dbc_start_tx(port);
+	}
+
 	spin_unlock_irqrestore(&port->port_lock, flags);
 
-	return count;
+	return written;
 }
 
 static int dbc_tty_put_char(struct tty_struct *tty, u8 ch)
@@ -230,7 +258,7 @@ static int dbc_tty_put_char(struct tty_struct *tty, u8 ch)
 	int			status;
 
 	spin_lock_irqsave(&port->port_lock, flags);
-	status = kfifo_put(&port->write_fifo, ch);
+	status = kfifo_put(&port->port.xmit_fifo, ch);
 	spin_unlock_irqrestore(&port->port_lock, flags);
 
 	return status;
@@ -253,7 +281,11 @@ static unsigned int dbc_tty_write_room(struct tty_struct *tty)
 	unsigned int		room;
 
 	spin_lock_irqsave(&port->port_lock, flags);
-	room = kfifo_avail(&port->write_fifo);
+	room = kfifo_avail(&port->port.xmit_fifo);
+
+	if (port->tx_boundary)
+		room = 0;
+
 	spin_unlock_irqrestore(&port->port_lock, flags);
 
 	return room;
@@ -266,7 +298,7 @@ static unsigned int dbc_tty_chars_in_buffer(struct tty_struct *tty)
 	unsigned int		chars;
 
 	spin_lock_irqsave(&port->port_lock, flags);
-	chars = kfifo_len(&port->write_fifo);
+	chars = kfifo_len(&port->port.xmit_fifo);
 	spin_unlock_irqrestore(&port->port_lock, flags);
 
 	return chars;
@@ -346,7 +378,7 @@ static void dbc_rx_push(struct tasklet_struct *t)
 			port->n_read = 0;
 		}
 
-		list_move(&req->list_pool, &port->read_pool);
+		list_move_tail(&req->list_pool, &port->read_pool);
 	}
 
 	if (do_push)
@@ -424,7 +456,8 @@ static int xhci_dbc_tty_register_device(struct xhci_dbc *dbc)
 		goto err_idr;
 	}
 
-	ret = kfifo_alloc(&port->write_fifo, DBC_WRITE_BUF_SIZE, GFP_KERNEL);
+	ret = kfifo_alloc(&port->port.xmit_fifo, DBC_WRITE_BUF_SIZE,
+			  GFP_KERNEL);
 	if (ret)
 		goto err_exit_port;
 
@@ -453,7 +486,7 @@ err_free_requests:
 	xhci_dbc_free_requests(&port->read_pool);
 	xhci_dbc_free_requests(&port->write_pool);
 err_free_fifo:
-	kfifo_free(&port->write_fifo);
+	kfifo_free(&port->port.xmit_fifo);
 err_exit_port:
 	idr_remove(&dbc_tty_minors, port->minor);
 err_idr:
@@ -478,7 +511,7 @@ static void xhci_dbc_tty_unregister_device(struct xhci_dbc *dbc)
 	idr_remove(&dbc_tty_minors, port->minor);
 	mutex_unlock(&dbc_tty_minors_lock);
 
-	kfifo_free(&port->write_fifo);
+	kfifo_free(&port->port.xmit_fifo);
 	xhci_dbc_free_requests(&port->read_pool);
 	xhci_dbc_free_requests(&port->read_queue);
 	xhci_dbc_free_requests(&port->write_pool);