usb_serial: API all change

USB serial likes to use port->tty back pointers for the real work it does and
to do so without any actual locking. Unfortunately when you consider hangup
events, hangup/parallel reopen or even worse hangup followed by parallel close
events the tty->port and port->tty pointers are not guaranteed to be the same
as port->tty is the active tty while tty->port is the port the tty may or
may not still be attached to.

So rework the entire API to pass the tty struct. For console cases we need
to pass both for now. This shows up multiple drivers that immediately crash
with USB console some of which have been fixed in the process.

Longer term we need a proper tty as console abstraction

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 20 insertions, 38 deletions

diff --git a/drivers/usb/serial/garmin_gps.c b/drivers/usb/serial/garmin_gps.c
index 8ce5a56a48e3..06cfa43c6f02 100644
--- a/drivers/usb/serial/garmin_gps.c
+++ b/drivers/usb/serial/garmin_gps.c
@@ -275,7 +275,7 @@ static inline int isAbortTrfCmnd(const unsigned char *buf)
 static void send_to_tty(struct usb_serial_port *port,
                         char *data, unsigned int actual_length)
 {
-        struct tty_struct *tty = port->tty;
+        struct tty_struct *tty = port->port.tty;
 
         if (tty && actual_length) {
 
@@ -970,7 +970,8 @@ static int garmin_init_session(struct usb_serial_port *port)
 
 
 
-static int garmin_open (struct usb_serial_port *port, struct file *filp)
+static int garmin_open (struct tty_struct *tty,
+                        struct usb_serial_port *port, struct file *filp)
 {
         unsigned long flags;
         int status = 0;
@@ -983,8 +984,8 @@ static int garmin_open (struct usb_serial_port *port, struct file *filp)
          * through, otherwise it is scheduled, and with high data rates (like
          * with OHCI) data can get lost.
          */
-        if (port->tty)
-                port->tty->low_latency = 1;
+        if (tty)
+                tty->low_latency = 1;
 
         spin_lock_irqsave(&garmin_data_p->lock, flags);
         garmin_data_p->mode  = initial_mode;
@@ -998,17 +999,16 @@ static int garmin_open (struct usb_serial_port *port, struct file *filp)
         usb_kill_urb (port->write_urb);
         usb_kill_urb (port->read_urb);
 
-        if (garmin_data_p->state == STATE_RESET) {
+        if (garmin_data_p->state == STATE_RESET)
                 status = garmin_init_session(port);
-        }
 
         garmin_data_p->state = STATE_ACTIVE;
-
         return status;
 }
 
 
-static void garmin_close (struct usb_serial_port *port, struct file * filp)
+static void garmin_close(struct tty_struct *tty,
+                        struct usb_serial_port *port, struct file * filp)
 {
         struct usb_serial *serial = port->serial;
         struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
@@ -1042,7 +1042,6 @@ static void garmin_close (struct usb_serial_port *port, struct file * filp)
         mutex_unlock(&port->serial->disc_mutex);
 }
 
-
 static void garmin_write_bulk_callback (struct urb *urb)
 {
         unsigned long flags;
@@ -1145,10 +1144,8 @@ static int garmin_write_bulk (struct usb_serial_port *port,
         return count;
 }
 
-
-
-static int garmin_write (struct usb_serial_port *port,
-                         const unsigned char *buf, int count)
+static int garmin_write (struct tty_struct *tty, struct usb_serial_port *port,
+                                         const unsigned char *buf, int count)
 {
         int pktid, pktsiz, len;
         struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
@@ -1158,7 +1155,6 @@ static int garmin_write (struct usb_serial_port *port,
 
         /* check for our private packets */
         if (count >= GARMIN_PKTHDR_LENGTH) {
-
                 len = PRIVPKTSIZ;
                 if (count < len)
                         len = count;
@@ -1226,8 +1222,9 @@ static int garmin_write (struct usb_serial_port *port,
 }
 
 
-static int garmin_write_room (struct usb_serial_port *port)
+static int garmin_write_room(struct tty_struct *tty)
 {
+        struct usb_serial_port *port = tty->driver_data;
         /*
          * Report back the bytes currently available in the output buffer.
          */
@@ -1236,20 +1233,6 @@ static int garmin_write_room (struct usb_serial_port *port)
 }
 
 
-static int garmin_chars_in_buffer (struct usb_serial_port *port)
-{
-        /*
-         * Report back the number of bytes currently in our input buffer.
-         * Will this lock up the driver - the buffer contains an incomplete
-         * package which will not be written to the device until it
-         * has been completed ?
-         */
-        //struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
-        //return garmin_data_p->insize;
-        return 0;
-}
-
-
 static void garmin_read_process(struct garmin_data * garmin_data_p,
                                  unsigned char *data, unsigned data_length)
 {
@@ -1468,10 +1451,11 @@ static int garmin_flush_queue(struct garmin_data * garmin_data_p)
 }
 
 
-static void garmin_throttle (struct usb_serial_port *port)
+static void garmin_throttle(struct tty_struct *tty)
 {
-        unsigned long flags;
+        struct usb_serial_port *port = tty->driver_data;
         struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+        unsigned long flags;
 
         dbg("%s - port %d", __func__, port->number);
         /* set flag, data received will be put into a queue
@@ -1482,10 +1466,11 @@ static void garmin_throttle (struct usb_serial_port *port)
 }
 
 
-static void garmin_unthrottle (struct usb_serial_port *port)
+static void garmin_unthrottle (struct tty_struct *tty)
 {
-        unsigned long flags;
+        struct usb_serial_port *port = tty->driver_data;
         struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+        unsigned long flags;
         int status;
 
         dbg("%s - port %d", __func__, port->number);
@@ -1507,8 +1492,6 @@ static void garmin_unthrottle (struct usb_serial_port *port)
         }
 }
 
-
-
 /*
  * The timer is currently only used to send queued packets to
  * the tty in cases where the protocol provides no own handshaking
@@ -1526,7 +1509,7 @@ static void timeout_handler(unsigned long data)
 
 
 
-static int garmin_attach (struct usb_serial *serial)
+static int garmin_attach(struct usb_serial *serial)
 {
         int status = 0;
         struct usb_serial_port *port = serial->port[0];
@@ -1556,7 +1539,7 @@ static int garmin_attach (struct usb_serial *serial)
 }
 
 
-static void garmin_shutdown (struct usb_serial *serial)
+static void garmin_shutdown(struct usb_serial *serial)
 {
         struct usb_serial_port *port = serial->port[0];
         struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
@@ -1588,7 +1571,6 @@ static struct usb_serial_driver garmin_device = {
         .shutdown            = garmin_shutdown,
         .write               = garmin_write,
         .write_room          = garmin_write_room,
-        .chars_in_buffer     = garmin_chars_in_buffer,
         .write_bulk_callback = garmin_write_bulk_callback,
         .read_bulk_callback  = garmin_read_bulk_callback,
         .read_int_callback   = garmin_read_int_callback,