1 files changed, 40 insertions, 54 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 2e900a98c3e3..d2b496750d59 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -321,7 +321,8 @@ static void n_tty_check_unthrottle(struct tty_struct *tty)
 
 static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
 {
-	*read_buf_addr(ldata, ldata->read_head++) = c;
+	*read_buf_addr(ldata, ldata->read_head) = c;
+	ldata->read_head++;
 }
 
 /**
@@ -351,13 +352,13 @@ static void n_tty_packet_mode_flush(struct tty_struct *tty)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&tty->ctrl_lock, flags);
 	if (tty->link->packet) {
+		spin_lock_irqsave(&tty->ctrl_lock, flags);
 		tty->ctrl_status |= TIOCPKT_FLUSHREAD;
+		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 		if (waitqueue_active(&tty->link->read_wait))
 			wake_up_interruptible(&tty->link->read_wait);
 	}
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 }
 
 /**
@@ -2123,12 +2124,11 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 {
 	struct n_tty_data *ldata = tty->disc_data;
 	unsigned char __user *b = buf;
-	DECLARE_WAITQUEUE(wait, current);
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 	int c;
 	int minimum, time;
 	ssize_t retval = 0;
 	long timeout;
-	unsigned long flags;
 	int packet;
 
 	c = job_control(tty, file);
@@ -2174,10 +2174,10 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 			unsigned char cs;
 			if (b != buf)
 				break;
-			spin_lock_irqsave(&tty->link->ctrl_lock, flags);
+			spin_lock_irq(&tty->link->ctrl_lock);
 			cs = tty->link->ctrl_status;
 			tty->link->ctrl_status = 0;
-			spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
+			spin_unlock_irq(&tty->link->ctrl_lock);
 			if (tty_put_user(tty, cs, b++)) {
 				retval = -EFAULT;
 				b--;
@@ -2186,10 +2186,6 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 			nr--;
 			break;
 		}
-		/* This statement must be first before checking for input
-		   so that any interrupt will set the state back to
-		   TASK_RUNNING. */
-		set_current_state(TASK_INTERRUPTIBLE);
 
 		if (((minimum - (b - buf)) < ldata->minimum_to_wake) &&
 		    ((minimum - (b - buf)) >= 1))
@@ -2197,45 +2193,29 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 
 		if (!input_available_p(tty, 0)) {
 			if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
-				up_read(&tty->termios_rwsem);
-				tty_flush_to_ldisc(tty);
-				down_read(&tty->termios_rwsem);
-				if (!input_available_p(tty, 0)) {
-					retval = -EIO;
-					break;
-				}
-			} else {
-				if (tty_hung_up_p(file))
-					break;
-				if (!timeout)
-					break;
-				if (file->f_flags & O_NONBLOCK) {
-					retval = -EAGAIN;
-					break;
-				}
-				if (signal_pending(current)) {
-					retval = -ERESTARTSYS;
-					break;
-				}
-				n_tty_set_room(tty);
-				up_read(&tty->termios_rwsem);
-
-				timeout = schedule_timeout(timeout);
-
-				down_read(&tty->termios_rwsem);
-				continue;
+				retval = -EIO;
+				break;
 			}
-		}
-		__set_current_state(TASK_RUNNING);
-
-		/* Deal with packet mode. */
-		if (packet && b == buf) {
-			if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
-				retval = -EFAULT;
-				b--;
+			if (tty_hung_up_p(file))
+				break;
+			if (!timeout)
+				break;
+			if (file->f_flags & O_NONBLOCK) {
+				retval = -EAGAIN;
 				break;
 			}
-			nr--;
+			if (signal_pending(current)) {
+				retval = -ERESTARTSYS;
+				break;
+			}
+			n_tty_set_room(tty);
+			up_read(&tty->termios_rwsem);
+
+			timeout = wait_woken(&wait, TASK_INTERRUPTIBLE,
+					     timeout);
+
+			down_read(&tty->termios_rwsem);
+			continue;
 		}
 
 		if (ldata->icanon && !L_EXTPROC(tty)) {
@@ -2247,8 +2227,17 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 				break;
 		} else {
 			int uncopied;
-			/* The copy function takes the read lock and handles
-			   locking internally for this case */
+
+			/* Deal with packet mode. */
+			if (packet && b == buf) {
+				if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
+					retval = -EFAULT;
+					b--;
+					break;
+				}
+				nr--;
+			}
+
 			uncopied = copy_from_read_buf(tty, &b, &nr);
 			uncopied += copy_from_read_buf(tty, &b, &nr);
 			if (uncopied) {
@@ -2273,7 +2262,6 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 
 	mutex_unlock(&ldata->atomic_read_lock);
 
-	__set_current_state(TASK_RUNNING);
 	if (b - buf)
 		retval = b - buf;
 
@@ -2306,7 +2294,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 			   const unsigned char *buf, size_t nr)
 {
 	const unsigned char *b = buf;
-	DECLARE_WAITQUEUE(wait, current);
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 	int c;
 	ssize_t retval = 0;
 
@@ -2324,7 +2312,6 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 
 	add_wait_queue(&tty->write_wait, &wait);
 	while (1) {
-		set_current_state(TASK_INTERRUPTIBLE);
 		if (signal_pending(current)) {
 			retval = -ERESTARTSYS;
 			break;
@@ -2378,12 +2365,11 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 		}
 		up_read(&tty->termios_rwsem);
 
-		schedule();
+		wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
 
 		down_read(&tty->termios_rwsem);
 	}
 break_out:
-	__set_current_state(TASK_RUNNING);
 	remove_wait_queue(&tty->write_wait, &wait);
 	if (b - buf != nr && tty->fasync)
 		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);