USB: cypress_m8: switch to generic TIOCMIWAIT implementation

Switch to the generic TIOCMIWAIT implementation which does not suffer
from the races involved when using the deprecated sleep_on functions.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 16 insertions, 47 deletions

diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index 07e003398613..763d1c59f8fc 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -113,7 +113,7 @@ struct cypress_private {
         int baud_rate;                     /* stores current baud rate in
                                               integer form */
         int isthrottled;                   /* if throttled, discard reads */
-        char prev_status, diff_status;     /* used for TIOCMIWAIT */
+        char prev_status;                  /* used for TIOCMIWAIT */
         /* we pass a pointer to this as the argument sent to
            cypress_set_termios old_termios */
         struct ktermios tmp_termios;       /* stores the old termios settings */
@@ -136,7 +136,6 @@ static void cypress_set_termios(struct tty_struct *tty,
 static int  cypress_tiocmget(struct tty_struct *tty);
 static int  cypress_tiocmset(struct tty_struct *tty,
                         unsigned int set, unsigned int clear);
-static int  cypress_tiocmiwait(struct tty_struct *tty, unsigned long arg);
 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);
@@ -162,7 +161,7 @@ static struct usb_serial_driver cypress_earthmate_device = {
         .set_termios =                  cypress_set_termios,
         .tiocmget =                     cypress_tiocmget,
         .tiocmset =                     cypress_tiocmset,
-        .tiocmiwait =                   cypress_tiocmiwait,
+        .tiocmiwait =                   usb_serial_generic_tiocmiwait,
         .chars_in_buffer =              cypress_chars_in_buffer,
         .throttle =                     cypress_throttle,
         .unthrottle =                   cypress_unthrottle,
@@ -188,7 +187,7 @@ static struct usb_serial_driver cypress_hidcom_device = {
         .set_termios =                  cypress_set_termios,
         .tiocmget =                     cypress_tiocmget,
         .tiocmset =                     cypress_tiocmset,
-        .tiocmiwait =                   cypress_tiocmiwait,
+        .tiocmiwait =                   usb_serial_generic_tiocmiwait,
         .chars_in_buffer =              cypress_chars_in_buffer,
         .throttle =                     cypress_throttle,
         .unthrottle =                   cypress_unthrottle,
@@ -214,7 +213,7 @@ static struct usb_serial_driver cypress_ca42v2_device = {
         .set_termios =                  cypress_set_termios,
         .tiocmget =                     cypress_tiocmget,
         .tiocmset =                     cypress_tiocmset,
-        .tiocmiwait =                   cypress_tiocmiwait,
+        .tiocmiwait =                   usb_serial_generic_tiocmiwait,
         .chars_in_buffer =              cypress_chars_in_buffer,
         .throttle =                     cypress_throttle,
         .unthrottle =                   cypress_unthrottle,
@@ -864,45 +863,6 @@ static int cypress_tiocmset(struct tty_struct *tty,
         return cypress_write(tty, port, NULL, 0);
 }
 
-
-static int cypress_tiocmiwait(struct tty_struct *tty, unsigned long arg)
-{
-        struct usb_serial_port *port = tty->driver_data;
-        struct cypress_private *priv = usb_get_serial_port_data(port);
-        char diff;
-
-        for (;;) {
-                interruptible_sleep_on(&port->port.delta_msr_wait);
-                /* see if a signal did it */
-                if (signal_pending(current))
-                        return -ERESTARTSYS;
-
-                if (port->serial->disconnected)
-                        return -EIO;
-
-                diff = priv->diff_status;
-                if (diff == 0)
-                        return -EIO; /* no change => error */
-
-                /* consume all events */
-                priv->diff_status = 0;
-
-                /* return 0 if caller wanted to know about
-                   these bits */
-                if (((arg & TIOCM_RNG) && (diff & UART_RI))  ||
-                        ((arg & TIOCM_DSR) && (diff & UART_DSR)) ||
-                        ((arg & TIOCM_CD)  && (diff & UART_CD))  ||
-                        ((arg & TIOCM_CTS) && (diff & UART_CTS)))
-                        return 0;
-                /* otherwise caller can't care less about what
-                 * happened, and so we continue to wait for
-                 * more events.
-                 */
-        }
-
-        return 0;
-}
-
 static void cypress_set_termios(struct tty_struct *tty,
         struct usb_serial_port *port, struct ktermios *old_termios)
 {
@@ -1185,11 +1145,20 @@ static void cypress_read_int_callback(struct urb *urb)
         spin_lock_irqsave(&priv->lock, flags);
         /* check to see if status has changed */
         if (priv->current_status != priv->prev_status) {
-                priv->diff_status |= priv->current_status ^
-                        priv->prev_status;
+                u8 delta = priv->current_status ^ priv->prev_status;
+
+                if (delta & UART_MSR_MASK) {
+                        if (delta & UART_CTS)
+                                port->icount.cts++;
+                        if (delta & UART_DSR)
+                                port->icount.dsr++;
+                        if (delta & UART_RI)
+                                port->icount.rng++;
+                        if (delta & UART_CD)
+                                port->icount.dcd++;
 
-                if (priv->diff_status & UART_MSR_MASK)
                         wake_up_interruptible(&port->port.delta_msr_wait);
+                }
 
                 priv->prev_status = priv->current_status;
         }