From 6d6eb571d74b45a55c69db71276682faca652b69 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon, 3 Aug 2009 14:54:56 -0700
Subject: [PATCH] --- yaml --- r: 156374 b: refs/heads/master c:
 cbe9352fa08f90aa03b4dbf1bbabfc95d196e562 h: refs/heads/master v: v3

---
 [refs]                         |  2 +-
 trunk/drivers/char/tty_ldisc.c | 17 ++++++++++++-----
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/[refs] b/[refs]
index 2b0daa81de54..43efe02f4918 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 65b770468e98941e45e19780dff9283e663e6b8b
+refs/heads/master: cbe9352fa08f90aa03b4dbf1bbabfc95d196e562
diff --git a/trunk/drivers/char/tty_ldisc.c b/trunk/drivers/char/tty_ldisc.c
index be55dfcf59ac..1733d3439ad2 100644
--- a/trunk/drivers/char/tty_ldisc.c
+++ b/trunk/drivers/char/tty_ldisc.c
@@ -55,25 +55,32 @@ static inline struct tty_ldisc *get_ldisc(struct tty_ldisc *ld)
 	return ld;
 }
 
-static inline void put_ldisc(struct tty_ldisc *ld)
+static void put_ldisc(struct tty_ldisc *ld)
 {
+	unsigned long flags;
+
 	if (WARN_ON_ONCE(!ld))
 		return;
 
 	/*
 	 * If this is the last user, free the ldisc, and
 	 * release the ldisc ops.
+	 *
+	 * We really want an "atomic_dec_and_lock_irqsave()",
+	 * but we don't have it, so this does it by hand.
 	 */
-	if (atomic_dec_and_test(&ld->users)) {
-		unsigned long flags;
+	local_irq_save(flags);
+	if (atomic_dec_and_lock(&ld->users, &tty_ldisc_lock)) {
 		struct tty_ldisc_ops *ldo = ld->ops;
 
-		kfree(ld);
-		spin_lock_irqsave(&tty_ldisc_lock, flags);
 		ldo->refcount--;
 		module_put(ldo->owner);
 		spin_unlock_irqrestore(&tty_ldisc_lock, flags);
+
+		kfree(ld);
+		return;
 	}
+	local_irq_restore(flags);
 }
 
 /**