From 9ee90139576b2efd36f7526935a370ce3deb2da1 Mon Sep 17 00:00:00 2001
From: Peter Hurley <peter@hurleysoftware.com>
Date: Mon, 11 Mar 2013 16:44:25 -0400
Subject: [PATCH] --- yaml --- r: 364253 b: refs/heads/master c:
 2276ad9765b395577442d6ddf748f72c329234ae h: refs/heads/master i:   364251:
 e1a469782799c8f193c45df5b33bc57806e86e5f v: v3

---
 [refs]                        |  2 +-
 trunk/drivers/tty/tty_ldisc.c | 38 +++++++++++++++++------------------
 2 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/[refs] b/[refs]
index 71fc42d58bfb..6580293ca363 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 168942c9fa01916173a7b72ac67e1d218d571013
+refs/heads/master: 2276ad9765b395577442d6ddf748f72c329234ae
diff --git a/trunk/drivers/tty/tty_ldisc.c b/trunk/drivers/tty/tty_ldisc.c
index c5b848a78e49..fa0170e1b082 100644
--- a/trunk/drivers/tty/tty_ldisc.c
+++ b/trunk/drivers/tty/tty_ldisc.c
@@ -558,29 +558,29 @@ static int tty_ldisc_wait_idle(struct tty_struct *tty, long timeout)
  *	have been halted for this to guarantee it remains idle.
  *
  *	Caller must hold legacy and ->ldisc_mutex.
+ *
+ *	NB: tty_set_ldisc() is prevented from changing the ldisc concurrently
+ *	with this function by checking the TTY_HUPPING flag.
  */
 static bool tty_ldisc_hangup_wait_idle(struct tty_struct *tty)
 {
-	while (tty->ldisc) {	/* Not yet closed */
-		if (atomic_read(&tty->ldisc->users) != 1) {
-			char cur_n[TASK_COMM_LEN], tty_n[64];
-			long timeout = 3 * HZ;
-			tty_unlock(tty);
-
-			while (tty_ldisc_wait_idle(tty, timeout) == -EBUSY) {
-				timeout = MAX_SCHEDULE_TIMEOUT;
-				printk_ratelimited(KERN_WARNING
-					"%s: waiting (%s) for %s took too long, but we keep waiting...\n",
-					__func__, get_task_comm(cur_n, current),
-					tty_name(tty, tty_n));
-			}
-			/* must reacquire both locks and preserve lock order */
-			mutex_unlock(&tty->ldisc_mutex);
-			tty_lock(tty);
-			mutex_lock(&tty->ldisc_mutex);
-			continue;
+	char cur_n[TASK_COMM_LEN], tty_n[64];
+	long timeout = 3 * HZ;
+
+	if (tty->ldisc) {	/* Not yet closed */
+		tty_unlock(tty);
+
+		while (tty_ldisc_wait_idle(tty, timeout) == -EBUSY) {
+			timeout = MAX_SCHEDULE_TIMEOUT;
+			printk_ratelimited(KERN_WARNING
+				"%s: waiting (%s) for %s took too long, but we keep waiting...\n",
+				__func__, get_task_comm(cur_n, current),
+				tty_name(tty, tty_n));
 		}
-		break;
+		/* must reacquire both locks and preserve lock order */
+		mutex_unlock(&tty->ldisc_mutex);
+		tty_lock(tty);
+		mutex_lock(&tty->ldisc_mutex);
 	}
 	return !!tty->ldisc;
 }