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path: root/drivers/usb/host/xhci-dbgtty.c
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Diffstat (limited to 'drivers/usb/host/xhci-dbgtty.c')
-rw-r--r--drivers/usb/host/xhci-dbgtty.c23
1 files changed, 22 insertions, 1 deletions
diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c
index d894081d8d15..57cdda4e09c8 100644
--- a/drivers/usb/host/xhci-dbgtty.c
+++ b/drivers/usb/host/xhci-dbgtty.c
@@ -47,7 +47,7 @@ dbc_kfifo_to_req(struct dbc_port *port, char *packet)
return len;
}
-static int dbc_start_tx(struct dbc_port *port)
+static int dbc_do_start_tx(struct dbc_port *port)
__releases(&port->port_lock)
__acquires(&port->port_lock)
{
@@ -57,6 +57,8 @@ static int dbc_start_tx(struct dbc_port *port)
bool do_tty_wake = false;
struct list_head *pool = &port->write_pool;
+ port->tx_running = true;
+
while (!list_empty(pool)) {
req = list_entry(pool->next, struct dbc_request, list_pool);
len = dbc_kfifo_to_req(port, req->buf);
@@ -77,12 +79,25 @@ static int dbc_start_tx(struct dbc_port *port)
}
}
+ port->tx_running = false;
+
if (do_tty_wake && port->port.tty)
tty_wakeup(port->port.tty);
return status;
}
+/* must be called with port->port_lock held */
+static int dbc_start_tx(struct dbc_port *port)
+{
+ lockdep_assert_held(&port->port_lock);
+
+ if (port->tx_running)
+ return -EBUSY;
+
+ return dbc_do_start_tx(port);
+}
+
static void dbc_start_rx(struct dbc_port *port)
__releases(&port->port_lock)
__acquires(&port->port_lock)
@@ -535,6 +550,12 @@ static void xhci_dbc_tty_unregister_device(struct xhci_dbc *dbc)
if (!port->registered)
return;
+ /*
+ * Hang up the TTY. This wakes up any blocked
+ * writers and causes subsequent writes to fail.
+ */
+ tty_vhangup(port->port.tty);
+
tty_unregister_device(dbc_tty_driver, port->minor);
xhci_dbc_tty_exit_port(port);
port->registered = false;