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, 64 insertions, 53 deletions

diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index 0230d3c0888a..6999d3372d85 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -167,18 +167,18 @@ static int  cypress_earthmate_startup	(struct usb_serial *serial);
 static int  cypress_hidcom_startup      (struct usb_serial *serial);
 static int  cypress_ca42v2_startup      (struct usb_serial *serial);
 static void cypress_shutdown            (struct usb_serial *serial);
-static int  cypress_open                (struct usb_serial_port *port, struct file *filp);
-static void cypress_close               (struct usb_serial_port *port, struct file *filp);
-static int  cypress_write               (struct usb_serial_port *port, const unsigned char *buf, int count);
+static int  cypress_open                (struct tty_struct *tty, struct usb_serial_port *port, struct file *filp);
+static void cypress_close               (struct tty_struct *tty, struct usb_serial_port *port, struct file *filp);
+static int  cypress_write               (struct tty_struct *tty, struct usb_serial_port *port, const unsigned char *buf, int count);
 static void cypress_send                (struct usb_serial_port *port);
-static int  cypress_write_room          (struct usb_serial_port *port);
-static int  cypress_ioctl               (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg);
-static void cypress_set_termios         (struct usb_serial_port *port, struct ktermios * old);
-static int  cypress_tiocmget            (struct usb_serial_port *port, struct file *file);
-static int  cypress_tiocmset            (struct usb_serial_port *port, struct file *file, unsigned int set, unsigned int clear);
-static int  cypress_chars_in_buffer     (struct usb_serial_port *port);
-static void cypress_throttle            (struct usb_serial_port *port);
-static void cypress_unthrottle          (struct usb_serial_port *port);
+static int  cypress_write_room          (struct tty_struct *tty);
+static int  cypress_ioctl               (struct tty_struct *tty, struct file * file, unsigned int cmd, unsigned long arg);
+static void cypress_set_termios         (struct tty_struct *tty, struct usb_serial_port *port, struct ktermios * old);
+static int  cypress_tiocmget            (struct tty_struct *tty, struct file *file);
+static int  cypress_tiocmset            (struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear);
+static int  cypress_chars_in_buffer     (struct tty_struct *tty);
+static void cypress_throttle            (struct tty_struct *tty);
+static void cypress_unthrottle          (struct tty_struct *tty);
 static void cypress_set_dead            (struct usb_serial_port *port);
 static void cypress_read_int_callback   (struct urb *urb);
 static void cypress_write_int_callback  (struct urb *urb);
@@ -322,8 +322,10 @@ static int analyze_baud_rate(struct usb_serial_port *port, speed_t new_rate)
 
 
 /* This function can either set or retrieve the current serial line settings */
-static int cypress_serial_control (struct usb_serial_port *port, speed_t baud_rate, int data_bits, int stop_bits,
-                                   int parity_enable, int parity_type, int reset, int cypress_request_type)
+static int cypress_serial_control (struct tty_struct *tty,
+        struct usb_serial_port *port, speed_t baud_rate, int data_bits,
+        int stop_bits, int parity_enable, int parity_type, int reset,
+        int cypress_request_type)
 {
         int new_baudrate = 0, retval = 0, tries = 0;
         struct cypress_private *priv;
@@ -395,7 +397,7 @@ static int cypress_serial_control (struct usb_serial_port *port, speed_t baud_ra
                                 spin_unlock_irqrestore(&priv->lock, flags);
                                 /* If we asked for a speed change encode it */
                                 if (baud_rate)
-                                        tty_encode_baud_rate(port->tty,
+                                        tty_encode_baud_rate(tty,
                                                         new_baudrate, new_baudrate);
                         }
                 break;
@@ -611,7 +613,8 @@ static void cypress_shutdown (struct usb_serial *serial)
 }
 
 
-static int cypress_open (struct usb_serial_port *port, struct file *filp)
+static int cypress_open(struct tty_struct *tty,
+                        struct usb_serial_port *port, struct file *filp)
 {
         struct cypress_private *priv = usb_get_serial_port_data(port);
         struct usb_serial *serial = port->serial;
@@ -636,14 +639,15 @@ static int cypress_open (struct usb_serial_port *port, struct file *filp)
         spin_unlock_irqrestore(&priv->lock, flags);
 
         /* setting to zero could cause data loss */
-        port->tty->low_latency = 1;
+        if (tty)
+                tty->low_latency = 1;
 
         /* raise both lines and set termios */
         spin_lock_irqsave(&priv->lock, flags);
         priv->line_control = CONTROL_DTR | CONTROL_RTS;
         priv->cmd_ctrl = 1;
         spin_unlock_irqrestore(&priv->lock, flags);
-        result = cypress_write(port, NULL, 0);
+        result = cypress_write(tty, port, NULL, 0);
 
         if (result) {
                 dev_err(&port->dev, "%s - failed setting the control lines - error %d\n", __func__, result);
@@ -651,7 +655,8 @@ static int cypress_open (struct usb_serial_port *port, struct file *filp)
         } else
                 dbg("%s - success setting the control lines", __func__);
 
-        cypress_set_termios(port, &priv->tmp_termios);
+        if (tty)
+                cypress_set_termios(tty, port, &priv->tmp_termios);
 
         /* setup the port and start reading from the device */
         if(!port->interrupt_in_urb){
@@ -674,7 +679,8 @@ static int cypress_open (struct usb_serial_port *port, struct file *filp)
 } /* cypress_open */
 
 
-static void cypress_close(struct usb_serial_port *port, struct file * filp)
+static void cypress_close(struct tty_struct *tty,
+                        struct usb_serial_port *port, struct file * filp)
 {
         struct cypress_private *priv = usb_get_serial_port_data(port);
         unsigned int c_cflag;
@@ -688,7 +694,7 @@ static void cypress_close(struct usb_serial_port *port, struct file * filp)
         spin_lock_irq(&priv->lock);
         timeout = CYPRESS_CLOSING_WAIT;
         init_waitqueue_entry(&wait, current);
-        add_wait_queue(&port->tty->write_wait, &wait);
+        add_wait_queue(&tty->write_wait, &wait);
         for (;;) {
                 set_current_state(TASK_INTERRUPTIBLE);
                 if (cypress_buf_data_avail(priv->buf) == 0
@@ -701,7 +707,7 @@ static void cypress_close(struct usb_serial_port *port, struct file * filp)
                 spin_lock_irq(&priv->lock);
         }
         set_current_state(TASK_RUNNING);
-        remove_wait_queue(&port->tty->write_wait, &wait);
+        remove_wait_queue(&tty->write_wait, &wait);
         /* clear out any remaining data in the buffer */
         cypress_buf_clear(priv->buf);
         spin_unlock_irq(&priv->lock);
@@ -713,19 +719,21 @@ static void cypress_close(struct usb_serial_port *port, struct file * filp)
                 return;
         }
         /* wait for characters to drain from device */
-        bps = tty_get_baud_rate(port->tty);
-        if (bps > 1200)
-                timeout = max((HZ*2560)/bps,HZ/10);
-        else
-                timeout = 2*HZ;
-        schedule_timeout_interruptible(timeout);
+        if (tty) {
+                bps = tty_get_baud_rate(tty);
+                if (bps > 1200)
+                        timeout = max((HZ*2560)/bps,HZ/10);
+                else
+                        timeout = 2*HZ;
+                schedule_timeout_interruptible(timeout);
+        }
 
         dbg("%s - stopping urbs", __func__);
         usb_kill_urb (port->interrupt_in_urb);
         usb_kill_urb (port->interrupt_out_urb);
 
-        if (port->tty) {
-                c_cflag = port->tty->termios->c_cflag;
+        if (tty) {
+                c_cflag = tty->termios->c_cflag;
                 if (c_cflag & HUPCL) {
                         /* drop dtr and rts */
                         priv = usb_get_serial_port_data(port);
@@ -733,7 +741,7 @@ static void cypress_close(struct usb_serial_port *port, struct file * filp)
                         priv->line_control = 0;
                         priv->cmd_ctrl = 1;
                         spin_unlock_irq(&priv->lock);
-                        cypress_write(port, NULL, 0);
+                        cypress_write(tty, port, NULL, 0);
                 }
         }
 
@@ -744,7 +752,8 @@ static void cypress_close(struct usb_serial_port *port, struct file * filp)
 } /* cypress_close */
 
 
-static int cypress_write(struct usb_serial_port *port, const unsigned char *buf, int count)
+static int cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
+                                        const unsigned char *buf, int count)
 {
         struct cypress_private *priv = usb_get_serial_port_data(port);
         unsigned long flags;
@@ -878,8 +887,9 @@ send:
 
 
 /* returns how much space is available in the soft buffer */
-static int cypress_write_room(struct usb_serial_port *port)
+static int cypress_write_room(struct tty_struct *tty)
 {
+        struct usb_serial_port *port = tty->driver_data;
         struct cypress_private *priv = usb_get_serial_port_data(port);
         int room = 0;
         unsigned long flags;
@@ -895,8 +905,9 @@ static int cypress_write_room(struct usb_serial_port *port)
 }
 
 
-static int cypress_tiocmget (struct usb_serial_port *port, struct file *file)
+static int cypress_tiocmget(struct tty_struct *tty, struct file *file)
 {
+        struct usb_serial_port *port = tty->driver_data;
         struct cypress_private *priv = usb_get_serial_port_data(port);
         __u8 status, control;
         unsigned int result = 0;
@@ -922,9 +933,10 @@ static int cypress_tiocmget (struct usb_serial_port *port, struct file *file)
 }
 
 
-static int cypress_tiocmset (struct usb_serial_port *port, struct file *file,
+static int cypress_tiocmset(struct tty_struct *tty, struct file *file,
                                unsigned int set, unsigned int clear)
 {
+        struct usb_serial_port *port = tty->driver_data;
         struct cypress_private *priv = usb_get_serial_port_data(port);
         unsigned long flags;
         
@@ -942,12 +954,14 @@ static int cypress_tiocmset (struct usb_serial_port *port, struct file *file,
         priv->cmd_ctrl = 1;
         spin_unlock_irqrestore(&priv->lock, flags);
 
-        return cypress_write(port, NULL, 0);
+        return cypress_write(tty, port, NULL, 0);
 }
 
 
-static int cypress_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg)
+static int cypress_ioctl(struct tty_struct *tty, struct file * file,
+                                        unsigned int cmd, unsigned long arg)
 {
+        struct usb_serial_port *port = tty->driver_data;
         struct cypress_private *priv = usb_get_serial_port_data(port);
 
         dbg("%s - port %d, cmd 0x%.4x", __func__, port->number, cmd);
@@ -983,22 +997,18 @@ static int cypress_ioctl (struct usb_serial_port *port, struct file * file, unsi
                                 }
                         }
                         return 0;
-                        break;
                 default:
                         break;
         }
-
         dbg("%s - arg not supported - it was 0x%04x - check include/asm/ioctls.h", __func__, cmd);
-
         return -ENOIOCTLCMD;
 } /* cypress_ioctl */
 
 
-static void cypress_set_termios (struct usb_serial_port *port,
-                struct ktermios *old_termios)
+static void cypress_set_termios(struct tty_struct *tty,
+        struct usb_serial_port *port, struct ktermios *old_termios)
 {
         struct cypress_private *priv = usb_get_serial_port_data(port);
-        struct tty_struct *tty;
         int data_bits, stop_bits, parity_type, parity_enable;
         unsigned cflag, iflag;
         unsigned long flags;
@@ -1007,8 +1017,6 @@ static void cypress_set_termios (struct usb_serial_port *port,
 
         dbg("%s - port %d", __func__, port->number);
 
-        tty = port->tty;
-
         spin_lock_irqsave(&priv->lock, flags);
         if (!priv->termios_initialized) {
                 if (priv->chiptype == CT_EARTHMATE) {
@@ -1096,13 +1104,13 @@ static void cypress_set_termios (struct usb_serial_port *port,
                         "%d data_bits (+5)", __func__, stop_bits,
                         parity_enable, parity_type, data_bits);
 
-        cypress_serial_control(port, tty_get_baud_rate(tty), data_bits, stop_bits,
+        cypress_serial_control(tty, port, tty_get_baud_rate(tty), data_bits, stop_bits,
                         parity_enable, parity_type, 0, CYPRESS_SET_CONFIG);
 
         /* we perform a CYPRESS_GET_CONFIG so that the current settings are
          * filled into the private structure this should confirm that all is
          * working if it returns what we just set */
-        cypress_serial_control(port, 0, 0, 0, 0, 0, 0, CYPRESS_GET_CONFIG);
+        cypress_serial_control(tty, port, 0, 0, 0, 0, 0, 0, CYPRESS_GET_CONFIG);
 
         /* Here we can define custom tty settings for devices; the main tty
          * termios flag base comes from empeg.c */
@@ -1142,14 +1150,15 @@ static void cypress_set_termios (struct usb_serial_port *port,
         /* if necessary, set lines */
         if (linechange) {
                 priv->cmd_ctrl = 1;
-                cypress_write(port, NULL, 0);
+                cypress_write(tty, port, NULL, 0);
         }
 } /* cypress_set_termios */
 
 
 /* returns amount of data still left in soft buffer */
-static int cypress_chars_in_buffer(struct usb_serial_port *port)
+static int cypress_chars_in_buffer(struct tty_struct *tty)
 {
+        struct usb_serial_port *port = tty->driver_data;
         struct cypress_private *priv = usb_get_serial_port_data(port);
         int chars = 0;
         unsigned long flags;
@@ -1165,8 +1174,9 @@ static int cypress_chars_in_buffer(struct usb_serial_port *port)
 }
 
 
-static void cypress_throttle (struct usb_serial_port *port)
+static void cypress_throttle(struct tty_struct *tty)
 {
+        struct usb_serial_port *port = tty->driver_data;
         struct cypress_private *priv = usb_get_serial_port_data(port);
         unsigned long flags;
 
@@ -1178,8 +1188,9 @@ static void cypress_throttle (struct usb_serial_port *port)
 }
 
 
-static void cypress_unthrottle (struct usb_serial_port *port)
+static void cypress_unthrottle(struct tty_struct *tty)
 {
+        struct usb_serial_port *port = tty->driver_data;
         struct cypress_private *priv = usb_get_serial_port_data(port);
         int actually_throttled, result;
         unsigned long flags;
@@ -1251,7 +1262,7 @@ static void cypress_read_int_callback(struct urb *urb)
         }
         spin_unlock_irqrestore(&priv->lock, flags);
 
-        tty = port->tty;
+        tty = port->port.tty;
         if (!tty) {
                 dbg("%s - bad tty pointer - exiting", __func__);
                 return;
@@ -1327,7 +1338,7 @@ static void cypress_read_int_callback(struct urb *urb)
                                         data[i]);
                         tty_insert_flip_char(tty, data[i], tty_flag);
                 }
-                tty_flip_buffer_push(port->tty);
+                tty_flip_buffer_push(port->port.tty);
         }
 
         spin_lock_irqsave(&priv->lock, flags);
@@ -1339,7 +1350,7 @@ continue_read:
 
         /* Continue trying to always read... unless the port has closed. */
 
-        if (port->open_count > 0 && priv->comm_is_ok) {
+        if (port->port.count > 0 && priv->comm_is_ok) {
                 usb_fill_int_urb(port->interrupt_in_urb, port->serial->dev,
                                 usb_rcvintpipe(port->serial->dev,
                                         port->interrupt_in_endpointAddress),