tty: Untangle termios and mm mutex dependencies
Although this doesn't cause any problems it could potentially do so for
future mmap using devices. No real work is needed to sort it out so untangle
it before it causes problems
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c
index 2401dbc..8116bb1c 100644
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -626,9 +626,25 @@
return 0;
}
+static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
+{
+ mutex_lock(&tty->termios_mutex);
+ memcpy(kterm, tty->termios, sizeof(struct ktermios));
+ mutex_unlock(&tty->termios_mutex);
+}
+
+static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
+{
+ mutex_lock(&tty->termios_mutex);
+ memcpy(kterm, tty->termios_locked, sizeof(struct ktermios));
+ mutex_unlock(&tty->termios_mutex);
+}
+
static int get_termio(struct tty_struct *tty, struct termio __user *termio)
{
- if (kernel_termios_to_user_termio(termio, tty->termios))
+ struct ktermios kterm;
+ copy_termios(tty, &kterm);
+ if (kernel_termios_to_user_termio(termio, &kterm))
return -EFAULT;
return 0;
}
@@ -930,6 +946,8 @@
struct tty_struct *real_tty;
void __user *p = (void __user *)arg;
int ret = 0;
+ struct ktermios kterm;
+ struct termiox ktermx;
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_MASTER)
@@ -965,23 +983,20 @@
return set_termios(real_tty, p, TERMIOS_OLD);
#ifndef TCGETS2
case TCGETS:
- mutex_lock(&real_tty->termios_mutex);
- if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios))
+ copy_termios(real_tty, &kterm);
+ if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
ret = -EFAULT;
- mutex_unlock(&real_tty->termios_mutex);
return ret;
#else
case TCGETS:
- mutex_lock(&real_tty->termios_mutex);
- if (kernel_termios_to_user_termios_1((struct termios __user *)arg, real_tty->termios))
+ copy_termios(real_tty, &kterm);
+ if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
ret = -EFAULT;
- mutex_unlock(&real_tty->termios_mutex);
return ret;
case TCGETS2:
- mutex_lock(&real_tty->termios_mutex);
- if (kernel_termios_to_user_termios((struct termios2 __user *)arg, real_tty->termios))
+ copy_termios(real_tty, &kterm);
+ if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm))
ret = -EFAULT;
- mutex_unlock(&real_tty->termios_mutex);
return ret;
case TCSETSF2:
return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT);
@@ -1000,34 +1015,36 @@
return set_termios(real_tty, p, TERMIOS_TERMIO);
#ifndef TCGETS2
case TIOCGLCKTRMIOS:
- mutex_lock(&real_tty->termios_mutex);
- if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios_locked))
+ copy_termios_locked(real_tty, &kterm);
+ if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
ret = -EFAULT;
- mutex_unlock(&real_tty->termios_mutex);
return ret;
case TIOCSLCKTRMIOS:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- mutex_lock(&real_tty->termios_mutex);
- if (user_termios_to_kernel_termios(real_tty->termios_locked,
+ copy_termios_locked(real_tty, &kterm);
+ if (user_termios_to_kernel_termios(&kterm,
(struct termios __user *) arg))
- ret = -EFAULT;
+ return -EFAULT;
+ mutex_lock(&real_tty->termios_mutex);
+ memcpy(real_tty->termios_locked, &kterm, sizeof(struct ktermios));
mutex_unlock(&real_tty->termios_mutex);
- return ret;
+ return 0;
#else
case TIOCGLCKTRMIOS:
- mutex_lock(&real_tty->termios_mutex);
- if (kernel_termios_to_user_termios_1((struct termios __user *)arg, real_tty->termios_locked))
+ copy_termios_locked(real_tty, &kterm);
+ if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
ret = -EFAULT;
- mutex_unlock(&real_tty->termios_mutex);
return ret;
case TIOCSLCKTRMIOS:
if (!capable(CAP_SYS_ADMIN))
- ret = -EPERM;
- mutex_lock(&real_tty->termios_mutex);
- if (user_termios_to_kernel_termios_1(real_tty->termios_locked,
+ return -EPERM;
+ copy_termios_locked(real_tty, &kterm);
+ if (user_termios_to_kernel_termios_1(&kterm,
(struct termios __user *) arg))
- ret = -EFAULT;
+ return -EFAULT;
+ mutex_lock(&real_tty->termios_mutex);
+ memcpy(real_tty->termios_locked, &kterm, sizeof(struct ktermios));
mutex_unlock(&real_tty->termios_mutex);
return ret;
#endif
@@ -1036,9 +1053,10 @@
if (real_tty->termiox == NULL)
return -EINVAL;
mutex_lock(&real_tty->termios_mutex);
- if (copy_to_user(p, real_tty->termiox, sizeof(struct termiox)))
- ret = -EFAULT;
+ memcpy(&ktermx, real_tty->termiox, sizeof(struct termiox));
mutex_unlock(&real_tty->termios_mutex);
+ if (copy_to_user(p, &ktermx, sizeof(struct termiox)))
+ ret = -EFAULT;
return ret;
case TCSETX:
return set_termiox(real_tty, p, 0);
@@ -1048,10 +1066,9 @@
return set_termiox(real_tty, p, TERMIOS_FLUSH);
#endif
case TIOCGSOFTCAR:
- mutex_lock(&real_tty->termios_mutex);
- ret = put_user(C_CLOCAL(real_tty) ? 1 : 0,
+ copy_termios(real_tty, &kterm);
+ ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
(int __user *)arg);
- mutex_unlock(&real_tty->termios_mutex);
return ret;
case TIOCSSOFTCAR:
if (get_user(arg, (unsigned int __user *) arg))