1 files changed, 20 insertions, 16 deletions

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index ff8605b4b4be..02e7f2d32d52 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -75,7 +75,8 @@ struct ftdi_private {
         unsigned long last_dtr_rts;     /* saved modem control outputs */
         struct async_icount     icount;
         wait_queue_head_t delta_msr_wait; /* Used for TIOCMIWAIT */
-        char prev_status, diff_status;        /* Used for TIOCMIWAIT */
+        char prev_status;        /* Used for TIOCMIWAIT */
+        bool dev_gone;        /* Used to abort TIOCMIWAIT */
         char transmit_empty;    /* If transmitter is empty or not */
         struct usb_serial_port *port;
         __u16 interface;        /* FT2232C, FT2232H or FT4232H port interface
@@ -1681,6 +1682,7 @@ static int ftdi_sio_port_probe(struct usb_serial_port *port)
         init_waitqueue_head(&priv->delta_msr_wait);
 
         priv->flags = ASYNC_LOW_LATENCY;
+        priv->dev_gone = false;
 
         if (quirk && quirk->port_probe)
                 quirk->port_probe(priv);
@@ -1839,6 +1841,9 @@ static int ftdi_sio_port_remove(struct usb_serial_port *port)
 
         dbg("%s", __func__);
 
+        priv->dev_gone = true;
+        wake_up_interruptible_all(&priv->delta_msr_wait);
+
         remove_sysfs_attrs(port);
 
         kref_put(&priv->kref, ftdi_sio_priv_release);
@@ -1982,17 +1987,19 @@ static int ftdi_process_packet(struct tty_struct *tty,
            N.B. packet may be processed more than once, but differences
            are only processed once.  */
         status = packet[0] & FTDI_STATUS_B0_MASK;
-        if (status & FTDI_RS0_CTS)
-                priv->icount.cts++;
-        if (status & FTDI_RS0_DSR)
-                priv->icount.dsr++;
-        if (status & FTDI_RS0_RI)
-                priv->icount.rng++;
-        if (status & FTDI_RS0_RLSD)
-                priv->icount.dcd++;
         if (status != priv->prev_status) {
-                priv->diff_status |= status ^ priv->prev_status;
-                wake_up_interruptible(&priv->delta_msr_wait);
+                char diff_status = status ^ priv->prev_status;
+
+                if (diff_status & FTDI_RS0_CTS)
+                        priv->icount.cts++;
+                if (diff_status & FTDI_RS0_DSR)
+                        priv->icount.dsr++;
+                if (diff_status & FTDI_RS0_RI)
+                        priv->icount.rng++;
+                if (diff_status & FTDI_RS0_RLSD)
+                        priv->icount.dcd++;
+
+                wake_up_interruptible_all(&priv->delta_msr_wait);
                 priv->prev_status = status;
         }
 
@@ -2395,15 +2402,12 @@ static int ftdi_ioctl(struct tty_struct *tty,
          */
         case TIOCMIWAIT:
                 cprev = priv->icount;
-                while (1) {
+                while (!priv->dev_gone) {
                         interruptible_sleep_on(&priv->delta_msr_wait);
                         /* see if a signal did it */
                         if (signal_pending(current))
                                 return -ERESTARTSYS;
                         cnow = priv->icount;
-                        if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
-                            cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
-                                return -EIO; /* no change => error */
                         if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
                             ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
                             ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
@@ -2412,7 +2416,7 @@ static int ftdi_ioctl(struct tty_struct *tty,
                         }
                         cprev = cnow;
                 }
-                /* not reached */
+                return -EIO;
                 break;
         case TIOCSERGETLSR:
                 return get_lsr_info(port, (struct serial_struct __user *)arg);