TTY: hso, use tty from tty_port

We switched tty refcounting there to the one provided by tty_port
helpers. So tty_port->tty is now protected by tty_port->lock, not by
hso_serial->serial_lock.

Side note: tty->driver_data does not need the lock, so it is needed
neither in open, nor in close paths.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Jan Dumon <j.dumon@option.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 13 insertions, 27 deletions

diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index ec782c7eabd8..813d70946d39 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -250,7 +250,6 @@ struct hso_serial {
 
         struct tty_port port;
         /* from usb_serial_port */
-        struct tty_struct *tty;
         spinlock_t serial_lock;
 
         int (*write_data) (struct hso_serial *serial);
@@ -1297,11 +1296,8 @@ static int hso_serial_open(struct tty_struct *tty, struct file *filp)
         kref_get(&serial->parent->ref);
 
         /* setup */
-        spin_lock_irq(&serial->serial_lock);
         tty->driver_data = serial;
-        tty_kref_put(serial->tty);
-        serial->tty = tty_kref_get(tty);
-        spin_unlock_irq(&serial->serial_lock);
+        tty_port_tty_set(&serial->port, tty);
 
         /* check for port already opened, if not set the termios */
         serial->port.count++;
@@ -1358,13 +1354,7 @@ static void hso_serial_close(struct tty_struct *tty, struct file *filp)
 
         if (serial->port.count <= 0) {
                 serial->port.count = 0;
-                spin_lock_irq(&serial->serial_lock);
-                if (serial->tty == tty) {
-                        serial->tty->driver_data = NULL;
-                        serial->tty = NULL;
-                        tty_kref_put(tty);
-                }
-                spin_unlock_irq(&serial->serial_lock);
+                tty_port_tty_set(&serial->port, NULL);
                 if (!usb_gone)
                         hso_stop_serial_device(serial->parent);
                 tasklet_kill(&serial->unthrottle_tasklet);
@@ -1947,14 +1937,13 @@ static void hso_std_serial_write_bulk_callback(struct urb *urb)
 
         spin_lock(&serial->serial_lock);
         serial->tx_urb_used = 0;
-        tty = tty_kref_get(serial->tty);
         spin_unlock(&serial->serial_lock);
         if (status) {
                 handle_usb_error(status, __func__, serial->parent);
-                tty_kref_put(tty);
                 return;
         }
         hso_put_activity(serial->parent);
+        tty = tty_port_tty_get(&serial->port);
         if (tty) {
                 tty_wakeup(tty);
                 tty_kref_put(tty);
@@ -1994,7 +1983,6 @@ static void ctrl_callback(struct urb *urb)
         struct hso_serial *serial = urb->context;
         struct usb_ctrlrequest *req;
         int status = urb->status;
-        struct tty_struct *tty;
 
         /* sanity check */
         if (!serial)
@@ -2002,11 +1990,9 @@ static void ctrl_callback(struct urb *urb)
 
         spin_lock(&serial->serial_lock);
         serial->tx_urb_used = 0;
-        tty = tty_kref_get(serial->tty);
         spin_unlock(&serial->serial_lock);
         if (status) {
                 handle_usb_error(status, __func__, serial->parent);
-                tty_kref_put(tty);
                 return;
         }
 
@@ -2024,13 +2010,15 @@ static void ctrl_callback(struct urb *urb)
                 put_rxbuf_data_and_resubmit_ctrl_urb(serial);
                 spin_unlock(&serial->serial_lock);
         } else {
+                struct tty_struct *tty = tty_port_tty_get(&serial->port);
                 hso_put_activity(serial->parent);
-                if (tty)
+                if (tty) {
                         tty_wakeup(tty);
+                        tty_kref_put(tty);
+                }
                 /* response to a write command */
                 hso_kick_transmit(serial);
         }
-        tty_kref_put(tty);
 }
 
 /* handle RX data for serial port */
@@ -2046,8 +2034,7 @@ static int put_rxbuf_data(struct urb *urb, struct hso_serial *serial)
                 return -2;
         }
 
-        /* All callers to put_rxbuf_data hold serial_lock */
-        tty = tty_kref_get(serial->tty);
+        tty = tty_port_tty_get(&serial->port);
 
         /* Push data to tty */
         if (tty) {
@@ -2067,12 +2054,12 @@ static int put_rxbuf_data(struct urb *urb, struct hso_serial *serial)
                         write_length_remaining -= curr_write_len;
                         tty_flip_buffer_push(tty);
                 }
+                tty_kref_put(tty);
         }
         if (write_length_remaining == 0) {
                 serial->curr_rx_urb_offset = 0;
                 serial->rx_urb_filled[hso_urb_to_index(serial, urb)] = 0;
         }
-        tty_kref_put(tty);
         return write_length_remaining;
 }
 
@@ -3166,13 +3153,12 @@ static void hso_free_interface(struct usb_interface *interface)
                 if (serial_table[i] &&
                     (serial_table[i]->interface == interface)) {
                         hso_dev = dev2ser(serial_table[i]);
-                        spin_lock_irq(&hso_dev->serial_lock);
-                        tty = tty_kref_get(hso_dev->tty);
-                        spin_unlock_irq(&hso_dev->serial_lock);
-                        if (tty)
+                        tty = tty_port_tty_get(&hso_dev->port);
+                        if (tty) {
                                 tty_hangup(tty);
+                                tty_kref_put(tty);
+                        }
                         mutex_lock(&hso_dev->parent->mutex);
-                        tty_kref_put(tty);
                         hso_dev->parent->usb_gone = 1;
                         mutex_unlock(&hso_dev->parent->mutex);
                         kref_put(&serial_table[i]->ref, hso_serial_ref_free);