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, 29 insertions, 64 deletions

diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index 29074c1ba22b..892020d48555 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -250,7 +250,8 @@ struct sierra_port_private {
         int ri_state;
 };
 
-static int sierra_send_setup(struct usb_serial_port *port)
+static int sierra_send_setup(struct tty_struct *tty,
+                                                struct usb_serial_port *port)
 {
         struct usb_serial *serial = port->serial;
         struct sierra_port_private *portdata;
@@ -260,7 +261,7 @@ static int sierra_send_setup(struct usb_serial_port *port)
 
         portdata = usb_get_serial_port_data(port);
 
-        if (port->tty) {
+        if (tty) {
                 int val = 0;
                 if (portdata->dtr_state)
                         val |= 0x01;
@@ -284,32 +285,17 @@ static int sierra_send_setup(struct usb_serial_port *port)
         return 0;
 }
 
-static void sierra_rx_throttle(struct usb_serial_port *port)
+static void sierra_set_termios(struct tty_struct *tty,
+                struct usb_serial_port *port, struct ktermios *old_termios)
 {
         dbg("%s", __func__);
+        tty_termios_copy_hw(tty->termios, old_termios);
+        sierra_send_setup(tty, port);
 }
 
-static void sierra_rx_unthrottle(struct usb_serial_port *port)
-{
-        dbg("%s", __func__);
-}
-
-static void sierra_break_ctl(struct usb_serial_port *port, int break_state)
-{
-        /* Unfortunately, I don't know how to send a break */
-        dbg("%s", __func__);
-}
-
-static void sierra_set_termios(struct usb_serial_port *port,
-                        struct ktermios *old_termios)
-{
-        dbg("%s", __func__);
-        tty_termios_copy_hw(port->tty->termios, old_termios);
-        sierra_send_setup(port);
-}
-
-static int sierra_tiocmget(struct usb_serial_port *port, struct file *file)
+static int sierra_tiocmget(struct tty_struct *tty, struct file *file)
 {
+        struct usb_serial_port *port = tty->driver_data;
         unsigned int value;
         struct sierra_port_private *portdata;
 
@@ -325,9 +311,10 @@ static int sierra_tiocmget(struct usb_serial_port *port, struct file *file)
         return value;
 }
 
-static int sierra_tiocmset(struct usb_serial_port *port, struct file *file,
+static int sierra_tiocmset(struct tty_struct *tty, struct file *file,
                         unsigned int set, unsigned int clear)
 {
+        struct usb_serial_port *port = tty->driver_data;
         struct sierra_port_private *portdata;
 
         portdata = usb_get_serial_port_data(port);
@@ -341,13 +328,7 @@ static int sierra_tiocmset(struct usb_serial_port *port, struct file *file,
                 portdata->rts_state = 0;
         if (clear & TIOCM_DTR)
                 portdata->dtr_state = 0;
-        return sierra_send_setup(port);
-}
-
-static int sierra_ioctl(struct usb_serial_port *port, struct file *file,
-                        unsigned int cmd, unsigned long arg)
-{
-        return -ENOIOCTLCMD;
+        return sierra_send_setup(tty, port);
 }
 
 static void sierra_outdat_callback(struct urb *urb)
@@ -374,8 +355,8 @@ static void sierra_outdat_callback(struct urb *urb)
 }
 
 /* Write */
-static int sierra_write(struct usb_serial_port *port,
-                        const unsigned char *buf, int count)
+static int sierra_write(struct tty_struct *tty, struct usb_serial_port *port,
+                                        const unsigned char *buf, int count)
 {
         struct sierra_port_private *portdata = usb_get_serial_port_data(port);
         struct usb_serial *serial = port->serial;
@@ -463,7 +444,7 @@ static void sierra_indat_callback(struct urb *urb)
                 dbg("%s: nonzero status: %d on endpoint %02x.",
                     __func__, status, endpoint);
         } else {
-                tty = port->tty;
+                tty = port->port.tty;
                 if (urb->actual_length) {
                         tty_buffer_request_room(tty, urb->actual_length);
                         tty_insert_flip_string(tty, data, urb->actual_length);
@@ -473,7 +454,7 @@ static void sierra_indat_callback(struct urb *urb)
                 }
 
                 /* Resubmit urb so we continue receiving */
-                if (port->open_count && status != -ESHUTDOWN) {
+                if (port->port.count && status != -ESHUTDOWN) {
                         err = usb_submit_urb(urb, GFP_ATOMIC);
                         if (err)
                                 dev_err(&port->dev, "resubmit read urb failed."
@@ -517,9 +498,9 @@ static void sierra_instat_callback(struct urb *urb)
                         portdata->dsr_state = ((signals & 0x02) ? 1 : 0);
                         portdata->ri_state = ((signals & 0x08) ? 1 : 0);
 
-                        if (port->tty && !C_CLOCAL(port->tty) &&
+                        if (port->port.tty && !C_CLOCAL(port->port.tty) &&
                                         old_dcd_state && !portdata->dcd_state)
-                                tty_hangup(port->tty);
+                                tty_hangup(port->port.tty);
                 } else {
                         dbg("%s: type %x req %x", __func__,
                                 req_pkt->bRequestType, req_pkt->bRequest);
@@ -537,8 +518,9 @@ static void sierra_instat_callback(struct urb *urb)
         }
 }
 
-static int sierra_write_room(struct usb_serial_port *port)
+static int sierra_write_room(struct tty_struct *tty)
 {
+        struct usb_serial_port *port = tty->driver_data;
         struct sierra_port_private *portdata = usb_get_serial_port_data(port);
         unsigned long flags;
 
@@ -557,22 +539,8 @@ static int sierra_write_room(struct usb_serial_port *port)
         return 2048;
 }
 
-static int sierra_chars_in_buffer(struct usb_serial_port *port)
-{
-        dbg("%s - port %d", __func__, port->number);
-
-        /*
-         * We can't really account for how much data we
-         * have sent out, but hasn't made it through to the
-         * device as we can't see the backend here, so just
-         * tell the tty layer that everything is flushed.
-         *
-         * FIXME: should walk the outstanding urbs info
-         */
-        return 0;
-}
-
-static int sierra_open(struct usb_serial_port *port, struct file *filp)
+static int sierra_open(struct tty_struct *tty,
+                        struct usb_serial_port *port, struct file *filp)
 {
         struct sierra_port_private *portdata;
         struct usb_serial *serial = port->serial;
@@ -612,9 +580,10 @@ static int sierra_open(struct usb_serial_port *port, struct file *filp)
                 }
         }
 
-        port->tty->low_latency = 1;
+        if (tty)
+                tty->low_latency = 1;
 
-        sierra_send_setup(port);
+        sierra_send_setup(tty, port);
 
         /* start up the interrupt endpoint if we have one */
         if (port->interrupt_in_urb) {
@@ -626,7 +595,8 @@ static int sierra_open(struct usb_serial_port *port, struct file *filp)
         return 0;
 }
 
-static void sierra_close(struct usb_serial_port *port, struct file *filp)
+static void sierra_close(struct tty_struct *tty,
+                        struct usb_serial_port *port, struct file *filp)
 {
         int i;
         struct usb_serial *serial = port->serial;
@@ -641,7 +611,7 @@ static void sierra_close(struct usb_serial_port *port, struct file *filp)
         if (serial->dev) {
                 mutex_lock(&serial->disc_mutex);
                 if (!serial->disconnected)
-                        sierra_send_setup(port);
+                        sierra_send_setup(tty, port);
                 mutex_unlock(&serial->disc_mutex);
 
                 /* Stop reading/writing urbs */
@@ -651,7 +621,7 @@ static void sierra_close(struct usb_serial_port *port, struct file *filp)
 
         usb_kill_urb(port->interrupt_in_urb);
 
-        port->tty = NULL;
+        port->port.tty = NULL;  /* FIXME */
 }
 
 static int sierra_startup(struct usb_serial *serial)
@@ -754,12 +724,7 @@ static struct usb_serial_driver sierra_device = {
         .close             = sierra_close,
         .write             = sierra_write,
         .write_room        = sierra_write_room,
-        .chars_in_buffer   = sierra_chars_in_buffer,
-        .throttle          = sierra_rx_throttle,
-        .unthrottle        = sierra_rx_unthrottle,
-        .ioctl             = sierra_ioctl,
         .set_termios       = sierra_set_termios,
-        .break_ctl         = sierra_break_ctl,
         .tiocmget          = sierra_tiocmget,
         .tiocmset          = sierra_tiocmset,
         .attach            = sierra_startup,