Merge tag 'regmap-3.4' into regmap-stride

regmap: Last minute bug fix for 3.4

This is a last minute bug fix that was only just noticed since the code
path that's being exercised here is one that is fairly rarely used.  The
changelog for the change itself is extremely clear and the code itself
is obvious to inspection so should be pretty safe.

Conflicts:
	drivers/base/regmap/regmap.c (overlap between the fix and stride code)

1 files changed, 20 insertions, 16 deletions

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index ff8605b4b4b..02e7f2d32d5 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);