From 0ee9cbb3c705903db9c258047d9ce87096e6a1a1 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
Date: Wed, 30 Apr 2008 00:53:32 -0700
Subject: tty_ioctl: locking for tty_wait_until_sent

This function still depends on the big kernel lock in some cases.  Push
locking into the function ready for removal of the BKL from ioctl call paths.

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 drivers/char/tty_ioctl.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

(limited to 'drivers/char')

diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c
index d6353d89b45..851cfcd2702 100644
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -21,6 +21,7 @@
 #include <linux/module.h>
 #include <linux/bitops.h>
 #include <linux/mutex.h>
+#include <linux/smp_lock.h>
 
 #include <asm/io.h>
 #include <asm/uaccess.h>
@@ -61,11 +62,13 @@ void tty_wait_until_sent(struct tty_struct *tty, long timeout)
 		return;
 	if (!timeout)
 		timeout = MAX_SCHEDULE_TIMEOUT;
+	lock_kernel();
 	if (wait_event_interruptible_timeout(tty->write_wait,
-			!tty->driver->chars_in_buffer(tty), timeout) < 0)
-		return;
-	if (tty->driver->wait_until_sent)
-		tty->driver->wait_until_sent(tty, timeout);
+			!tty->driver->chars_in_buffer(tty), timeout) >= 0) {
+		if (tty->driver->wait_until_sent)
+			tty->driver->wait_until_sent(tty, timeout);
+	}
+	unlock_kernel();
 }
 EXPORT_SYMBOL(tty_wait_until_sent);
 
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