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authorPeter Hurley <peter@hurleysoftware.com>2013-06-15 17:14:31 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-24 03:43:02 +0400
commitd8c1f929aa8164cd8eaa830068d2fa3159c0764a (patch)
tree1371cfe90fffdcb7115b39c77e0f729c109efc69 /drivers/tty/tty_ioctl.c
parentfb7aa03db605e4f0b9a62cd4c77177c2596edd95 (diff)
downloadlinux-d8c1f929aa8164cd8eaa830068d2fa3159c0764a.tar.xz
tty: Only guarantee termios read safety for throttle/unthrottle
No tty driver modifies termios during throttle() or unthrottle(). Therefore, only read safety is required. However, tty_throttle_safe and tty_unthrottle_safe must still be mutually exclusive; introduce throttle_mutex for that purpose. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_ioctl.c')
-rw-r--r--drivers/tty/tty_ioctl.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index 9ce20df8a2c8..03ba081c5772 100644
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -151,7 +151,7 @@ int tty_throttle_safe(struct tty_struct *tty)
{
int ret = 0;
- down_write(&tty->termios_rwsem);
+ mutex_lock(&tty->throttle_mutex);
if (!test_bit(TTY_THROTTLED, &tty->flags)) {
if (tty->flow_change != TTY_THROTTLE_SAFE)
ret = 1;
@@ -161,7 +161,7 @@ int tty_throttle_safe(struct tty_struct *tty)
tty->ops->throttle(tty);
}
}
- up_write(&tty->termios_rwsem);
+ mutex_unlock(&tty->throttle_mutex);
return ret;
}
@@ -182,7 +182,7 @@ int tty_unthrottle_safe(struct tty_struct *tty)
{
int ret = 0;
- down_write(&tty->termios_rwsem);
+ mutex_lock(&tty->throttle_mutex);
if (test_bit(TTY_THROTTLED, &tty->flags)) {
if (tty->flow_change != TTY_UNTHROTTLE_SAFE)
ret = 1;
@@ -192,7 +192,7 @@ int tty_unthrottle_safe(struct tty_struct *tty)
tty->ops->unthrottle(tty);
}
}
- up_write(&tty->termios_rwsem);
+ mutex_unlock(&tty->throttle_mutex);
return ret;
}