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, 38 insertions, 36 deletions

diff --git a/drivers/usb/serial/cp2101.c b/drivers/usb/serial/cp2101.c
index 2bc5576c443a..46c33fc9f6ce 100644
--- a/drivers/usb/serial/cp2101.c
+++ b/drivers/usb/serial/cp2101.c
@@ -37,15 +37,18 @@
 /*
  * Function Prototypes
  */
-static int cp2101_open(struct usb_serial_port*, struct file*);
-static void cp2101_cleanup(struct usb_serial_port*);
-static void cp2101_close(struct usb_serial_port*, struct file*);
-static void cp2101_get_termios(struct usb_serial_port*);
-static void cp2101_set_termios(struct usb_serial_port*, struct ktermios*);
-static int cp2101_tiocmget (struct usb_serial_port *, struct file *);
-static int cp2101_tiocmset (struct usb_serial_port *, struct file *,
+static int cp2101_open(struct tty_struct *, struct usb_serial_port *,
+                                                        struct file *);
+static void cp2101_cleanup(struct usb_serial_port *);
+static void cp2101_close(struct tty_struct *, struct usb_serial_port *,
+                                                        struct file*);
+static void cp2101_get_termios(struct tty_struct *);
+static void cp2101_set_termios(struct tty_struct *, struct usb_serial_port *,
+                                                        struct ktermios*);
+static int cp2101_tiocmget (struct tty_struct *, struct file *);
+static int cp2101_tiocmset (struct tty_struct *, struct file *,
                 unsigned int, unsigned int);
-static void cp2101_break_ctl(struct usb_serial_port*, int);
+static void cp2101_break_ctl(struct tty_struct *, int);
 static int cp2101_startup (struct usb_serial *);
 static void cp2101_shutdown(struct usb_serial*);
 
@@ -182,7 +185,7 @@ static struct usb_serial_driver cp2101_device = {
  * 'data' is a pointer to a pre-allocated array of integers large
  * enough to hold 'size' bytes (with 4 bytes to each integer)
  */
-static int cp2101_get_config(struct usb_serial_port* port, u8 request,
+static int cp2101_get_config(struct usb_serial_port *port, u8 request,
                 unsigned int *data, int size)
 {
         struct usb_serial *serial = port->serial;
@@ -228,7 +231,7 @@ static int cp2101_get_config(struct usb_serial_port* port, u8 request,
  * Values less than 16 bits wide are sent directly
  * 'size' is specified in bytes.
  */
-static int cp2101_set_config(struct usb_serial_port* port, u8 request,
+static int cp2101_set_config(struct usb_serial_port *port, u8 request,
                 unsigned int *data, int size)
 {
         struct usb_serial *serial = port->serial;
@@ -283,13 +286,14 @@ static int cp2101_set_config(struct usb_serial_port* port, u8 request,
  * Convenience function for calling cp2101_set_config on single data values
  * without requiring an integer pointer
  */
-static inline int cp2101_set_config_single(struct usb_serial_port* port,
+static inline int cp2101_set_config_single(struct usb_serial_port *port,
                 u8 request, unsigned int data)
 {
         return cp2101_set_config(port, request, &data, 2);
 }
 
-static int cp2101_open (struct usb_serial_port *port, struct file *filp)
+static int cp2101_open (struct tty_struct *tty, struct usb_serial_port *port,
+                                struct file *filp)
 {
         struct usb_serial *serial = port->serial;
         int result;
@@ -318,10 +322,10 @@ static int cp2101_open (struct usb_serial_port *port, struct file *filp)
         }
 
         /* Configure the termios structure */
-        cp2101_get_termios(port);
+        cp2101_get_termios(tty);
 
         /* Set the DTR and RTS pins low */
-        cp2101_tiocmset(port, NULL, TIOCM_DTR | TIOCM_RTS, 0);
+        cp2101_tiocmset(tty, NULL, TIOCM_DTR | TIOCM_RTS, 0);
 
         return 0;
 }
@@ -341,7 +345,8 @@ static void cp2101_cleanup (struct usb_serial_port *port)
         }
 }
 
-static void cp2101_close (struct usb_serial_port *port, struct file * filp)
+static void cp2101_close(struct tty_struct *tty, struct usb_serial_port *port,
+                                        struct file * filp)
 {
         dbg("%s - port %d", __func__, port->number);
 
@@ -362,19 +367,15 @@ static void cp2101_close (struct usb_serial_port *port, struct file * filp)
  * from the device, corrects any unsupported values, and configures the
  * termios structure to reflect the state of the device
  */
-static void cp2101_get_termios (struct usb_serial_port *port)
+static void cp2101_get_termios (struct tty_struct *tty)
 {
+        struct usb_serial_port *port = tty->driver_data;
         unsigned int cflag, modem_ctl[4];
         unsigned int baud;
         unsigned int bits;
 
         dbg("%s - port %d", __func__, port->number);
 
-        if (!port->tty || !port->tty->termios) {
-                dbg("%s - no tty structures", __func__);
-                return;
-        }
-
         cp2101_get_config(port, CP2101_BAUDRATE, &baud, 2);
         /* Convert to baudrate */
         if (baud)
@@ -382,8 +383,8 @@ static void cp2101_get_termios (struct usb_serial_port *port)
 
         dbg("%s - baud rate = %d", __func__, baud);
 
-        tty_encode_baud_rate(port->tty, baud, baud);
-        cflag = port->tty->termios->c_cflag;
+        tty_encode_baud_rate(tty, baud, baud);
+        cflag = tty->termios->c_cflag;
 
         cp2101_get_config(port, CP2101_BITS, &bits, 2);
         cflag &= ~CSIZE;
@@ -491,11 +492,11 @@ static void cp2101_get_termios (struct usb_serial_port *port)
                 cflag &= ~CRTSCTS;
         }
 
-        port->tty->termios->c_cflag = cflag;
+        tty->termios->c_cflag = cflag;
 }
 
-static void cp2101_set_termios (struct usb_serial_port *port,
-                struct ktermios *old_termios)
+static void cp2101_set_termios (struct tty_struct *tty,
+                struct usb_serial_port *port, struct ktermios *old_termios)
 {
         unsigned int cflag, old_cflag;
         unsigned int baud = 0, bits;
@@ -503,15 +504,13 @@ static void cp2101_set_termios (struct usb_serial_port *port,
 
         dbg("%s - port %d", __func__, port->number);
 
-        if (!port->tty || !port->tty->termios) {
-                dbg("%s - no tty structures", __func__);
+        if (!tty)
                 return;
-        }
-        port->tty->termios->c_cflag &= ~CMSPAR;
 
-        cflag = port->tty->termios->c_cflag;
+        tty->termios->c_cflag &= ~CMSPAR;
+        cflag = tty->termios->c_cflag;
         old_cflag = old_termios->c_cflag;
-        baud = tty_get_baud_rate(port->tty);
+        baud = tty_get_baud_rate(tty);
 
         /* If the baud rate is to be updated*/
         if (baud != tty_termios_baud_rate(old_termios)) {
@@ -554,7 +553,7 @@ static void cp2101_set_termios (struct usb_serial_port *port,
                 }
         }
         /* Report back the resulting baud rate */
-        tty_encode_baud_rate(port->tty, baud, baud);
+        tty_encode_baud_rate(tty, baud, baud);
 
         /* If the number of data bits is to be updated */
         if ((cflag & CSIZE) != (old_cflag & CSIZE)) {
@@ -651,9 +650,10 @@ static void cp2101_set_termios (struct usb_serial_port *port,
 
 }
 
-static int cp2101_tiocmset (struct usb_serial_port *port, struct file *file,
+static int cp2101_tiocmset (struct tty_struct *tty, struct file *file,
                 unsigned int set, unsigned int clear)
 {
+        struct usb_serial_port *port = tty->driver_data;
         unsigned int control = 0;
 
         dbg("%s - port %d", __func__, port->number);
@@ -681,8 +681,9 @@ static int cp2101_tiocmset (struct usb_serial_port *port, struct file *file,
 
 }
 
-static int cp2101_tiocmget (struct usb_serial_port *port, struct file *file)
+static int cp2101_tiocmget (struct tty_struct *tty, struct file *file)
 {
+        struct usb_serial_port *port = tty->driver_data;
         unsigned int control;
         int result;
 
@@ -702,8 +703,9 @@ static int cp2101_tiocmget (struct usb_serial_port *port, struct file *file)
         return result;
 }
 
-static void cp2101_break_ctl (struct usb_serial_port *port, int break_state)
+static void cp2101_break_ctl (struct tty_struct *tty, int break_state)
 {
+        struct usb_serial_port *port = tty->driver_data;
         unsigned int state;
 
         dbg("%s - port %d", __func__, port->number);