[PATCH v3 11/24] tty: Convert termios_mutex to termios_rwsem

From: Peter Hurley
Date: Mon Apr 15 2013 - 11:32:43 EST

termios is commonly accessed unsafely (especially by N_TTY)
because the existing mutex forces exclusive access.
Convert existing usage.

Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
drivers/net/irda/irtty-sir.c | 8 ++--
drivers/tty/n_tty.c | 2 +-
drivers/tty/pty.c | 4 +-
drivers/tty/tty_io.c | 14 +++----
drivers/tty/tty_ioctl.c | 90 ++++++++++++++++++++++----------------------
drivers/tty/tty_ldisc.c | 10 ++---
drivers/tty/vt/vt.c | 4 +-
include/linux/tty.h | 7 ++--
8 files changed, 70 insertions(+), 69 deletions(-)

diff --git a/drivers/net/irda/irtty-sir.c b/drivers/net/irda/irtty-sir.c
index a412671..177441a 100644
--- a/drivers/net/irda/irtty-sir.c
+++ b/drivers/net/irda/irtty-sir.c
@@ -123,14 +123,14 @@ static int irtty_change_speed(struct sir_dev *dev, unsigned speed)

tty = priv->tty;

- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
old_termios = tty->termios;
cflag = tty->termios.c_cflag;
tty_encode_baud_rate(tty, speed, speed);
if (tty->ops->set_termios)
tty->ops->set_termios(tty, &old_termios);
priv->io.speed = speed;
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);

return 0;
}
@@ -280,7 +280,7 @@ static inline void irtty_stop_receiver(struct tty_struct *tty, int stop)
struct ktermios old_termios;
int cflag;

- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
old_termios = tty->termios;
cflag = tty->termios.c_cflag;

@@ -292,7 +292,7 @@ static inline void irtty_stop_receiver(struct tty_struct *tty, int stop)
tty->termios.c_cflag = cflag;
if (tty->ops->set_termios)
tty->ops->set_termios(tty, &old_termios);
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
}

/*****************************************************************/
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index fdabd65..4389b6f 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -1540,7 +1540,7 @@ int is_ignored(int sig)
* guaranteed that this function will not be re-entered or in progress
* when the ldisc is closed.
*
- * Locking: Caller holds tty->termios_mutex
+ * Locking: Caller holds tty->termios_rwsem
*/

static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index c24b4db..50bec0d 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -290,7 +290,7 @@ static int pty_resize(struct tty_struct *tty, struct winsize *ws)
struct tty_struct *pty = tty->link;

/* For a PTY we need to lock the tty side */
- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
goto done;

@@ -317,7 +317,7 @@ static int pty_resize(struct tty_struct *tty, struct winsize *ws)
tty->winsize = *ws;
pty->winsize = *ws; /* Never used so will go away soon */
done:
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
return 0;
}

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 9dcb2ce..30201e6 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -550,7 +550,7 @@ EXPORT_SYMBOL_GPL(tty_wakeup);
* redirect lock for undoing redirection
* file list lock for manipulating list of ttys
* tty_ldisc_lock from called functions
- * termios_mutex resetting termios data
+ * termios_rwsem resetting termios data
* tasklist_lock to walk task list for hangup event
* ->siglock to protect ->signal/->sighand
*/
@@ -2166,7 +2166,7 @@ static int tiocsti(struct tty_struct *tty, char __user *p)
*
* Copies the kernel idea of the window size into the user buffer.
*
- * Locking: tty->termios_mutex is taken to ensure the winsize data
+ * Locking: tty->termios_rwsem is taken to ensure the winsize data
* is consistent.
*/

@@ -2174,9 +2174,9 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
{
int err;

- mutex_lock(&tty->termios_mutex);
+ down_read(&tty->termios_rwsem);
err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
- mutex_unlock(&tty->termios_mutex);
+ up_read(&tty->termios_rwsem);

return err ? -EFAULT: 0;
}
@@ -2197,7 +2197,7 @@ int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
unsigned long flags;

/* Lock the tty */
- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
goto done;
/* Get the PID values and reference them so we can
@@ -2212,7 +2212,7 @@ int tty_do_resize(struct tty_struct *tty, struct winsize *ws)

tty->winsize = *ws;
done:
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
return 0;
}
EXPORT_SYMBOL(tty_do_resize);
@@ -2951,7 +2951,7 @@ void initialize_tty_struct(struct tty_struct *tty,
tty->session = NULL;
tty->pgrp = NULL;
mutex_init(&tty->legacy_mutex);
- mutex_init(&tty->termios_mutex);
+ init_rwsem(&tty->termios_rwsem);
init_ldsem(&tty->ldisc_sem);
init_waitqueue_head(&tty->write_wait);
init_waitqueue_head(&tty->read_wait);
diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index 2febed5..490e499 100644
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -94,20 +94,20 @@ EXPORT_SYMBOL(tty_driver_flush_buffer);
* @tty: terminal
*
* Indicate that a tty should stop transmitting data down the stack.
- * Takes the termios mutex to protect against parallel throttle/unthrottle
+ * Takes the termios rwsem to protect against parallel throttle/unthrottle
* and also to ensure the driver can consistently reference its own
* termios data at this point when implementing software flow control.
*/

void tty_throttle(struct tty_struct *tty)
{
- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
/* check TTY_THROTTLED first so it indicates our state */
if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
tty->ops->throttle)
tty->ops->throttle(tty);
tty->flow_change = 0;
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
}
EXPORT_SYMBOL(tty_throttle);

@@ -116,7 +116,7 @@ EXPORT_SYMBOL(tty_throttle);
* @tty: terminal
*
* Indicate that a tty may continue transmitting data down the stack.
- * Takes the termios mutex to protect against parallel throttle/unthrottle
+ * Takes the termios rwsem to protect against parallel throttle/unthrottle
* and also to ensure the driver can consistently reference its own
* termios data at this point when implementing software flow control.
*
@@ -126,12 +126,12 @@ EXPORT_SYMBOL(tty_throttle);

void tty_unthrottle(struct tty_struct *tty)
{
- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
tty->ops->unthrottle)
tty->ops->unthrottle(tty);
tty->flow_change = 0;
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
}
EXPORT_SYMBOL(tty_unthrottle);

@@ -151,7 +151,7 @@ int tty_throttle_safe(struct tty_struct *tty)
{
int ret = 0;

- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
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);
}
}
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);

return ret;
}
@@ -182,7 +182,7 @@ int tty_unthrottle_safe(struct tty_struct *tty)
{
int ret = 0;

- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
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);
}
}
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);

return ret;
}
@@ -468,7 +468,7 @@ EXPORT_SYMBOL_GPL(tty_termios_encode_baud_rate);
* @obad: output baud rate
*
* Update the current termios data for the tty with the new speed
- * settings. The caller must hold the termios_mutex for the tty in
+ * settings. The caller must hold the termios_rwsem for the tty in
* question.
*/

@@ -556,7 +556,7 @@ EXPORT_SYMBOL(tty_termios_hw_change);
* is a bit of layering violation here with n_tty in terms of the
* internal knowledge of this function.
*
- * Locking: termios_mutex
+ * Locking: termios_rwsem
*/

int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios)
@@ -572,7 +572,7 @@ int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios)

/* FIXME: we need to decide on some locking/ordering semantics
for the set_termios notification eventually */
- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
old_termios = tty->termios;
tty->termios = *new_termios;
unset_locked_termios(&tty->termios, &old_termios, &tty->termios_locked);
@@ -614,7 +614,7 @@ int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios)
(ld->ops->set_termios)(tty, &old_termios);
tty_ldisc_deref(ld);
}
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
return 0;
}
EXPORT_SYMBOL_GPL(tty_set_termios);
@@ -629,7 +629,7 @@ EXPORT_SYMBOL_GPL(tty_set_termios);
* functions before using tty_set_termios to do the actual changes.
*
* Locking:
- * Called functions take ldisc and termios_mutex locks
+ * Called functions take ldisc and termios_rwsem locks
*/

static int set_termios(struct tty_struct *tty, void __user *arg, int opt)
@@ -641,9 +641,9 @@ static int set_termios(struct tty_struct *tty, void __user *arg, int opt)
if (retval)
return retval;

- mutex_lock(&tty->termios_mutex);
+ down_read(&tty->termios_rwsem);
tmp_termios = tty->termios;
- mutex_unlock(&tty->termios_mutex);
+ up_read(&tty->termios_rwsem);

if (opt & TERMIOS_TERMIO) {
if (user_termio_to_kernel_termios(&tmp_termios,
@@ -695,16 +695,16 @@ static int set_termios(struct tty_struct *tty, void __user *arg, int opt)

static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
{
- mutex_lock(&tty->termios_mutex);
+ down_read(&tty->termios_rwsem);
*kterm = tty->termios;
- mutex_unlock(&tty->termios_mutex);
+ up_read(&tty->termios_rwsem);
}

static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
{
- mutex_lock(&tty->termios_mutex);
+ down_read(&tty->termios_rwsem);
*kterm = tty->termios_locked;
- mutex_unlock(&tty->termios_mutex);
+ up_read(&tty->termios_rwsem);
}

static int get_termio(struct tty_struct *tty, struct termio __user *termio)
@@ -751,10 +751,10 @@ static int set_termiox(struct tty_struct *tty, void __user *arg, int opt)
return -ERESTARTSYS;
}

- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
if (tty->ops->set_termiox)
tty->ops->set_termiox(tty, &tnew);
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
return 0;
}

@@ -789,13 +789,13 @@ static int get_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
{
struct sgttyb tmp;

- mutex_lock(&tty->termios_mutex);
+ down_read(&tty->termios_rwsem);
tmp.sg_ispeed = tty->termios.c_ispeed;
tmp.sg_ospeed = tty->termios.c_ospeed;
tmp.sg_erase = tty->termios.c_cc[VERASE];
tmp.sg_kill = tty->termios.c_cc[VKILL];
tmp.sg_flags = get_sgflags(tty);
- mutex_unlock(&tty->termios_mutex);
+ up_read(&tty->termios_rwsem);

return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
}
@@ -834,7 +834,7 @@ static void set_sgflags(struct ktermios *termios, int flags)
* Updates a terminal from the legacy BSD style terminal information
* structure.
*
- * Locking: termios_mutex
+ * Locking: termios_rwsem
*/

static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
@@ -850,7 +850,7 @@ static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
return -EFAULT;

- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
termios = tty->termios;
termios.c_cc[VERASE] = tmp.sg_erase;
termios.c_cc[VKILL] = tmp.sg_kill;
@@ -860,7 +860,7 @@ static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
tty_termios_encode_baud_rate(&termios, termios.c_ispeed,
termios.c_ospeed);
#endif
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
tty_set_termios(tty, &termios);
return 0;
}
@@ -871,14 +871,14 @@ static int get_tchars(struct tty_struct *tty, struct tchars __user *tchars)
{
struct tchars tmp;

- mutex_lock(&tty->termios_mutex);
+ down_read(&tty->termios_rwsem);
tmp.t_intrc = tty->termios.c_cc[VINTR];
tmp.t_quitc = tty->termios.c_cc[VQUIT];
tmp.t_startc = tty->termios.c_cc[VSTART];
tmp.t_stopc = tty->termios.c_cc[VSTOP];
tmp.t_eofc = tty->termios.c_cc[VEOF];
tmp.t_brkc = tty->termios.c_cc[VEOL2]; /* what is brkc anyway? */
- mutex_unlock(&tty->termios_mutex);
+ up_read(&tty->termios_rwsem);
return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
}

@@ -888,14 +888,14 @@ static int set_tchars(struct tty_struct *tty, struct tchars __user *tchars)

if (copy_from_user(&tmp, tchars, sizeof(tmp)))
return -EFAULT;
- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
tty->termios.c_cc[VINTR] = tmp.t_intrc;
tty->termios.c_cc[VQUIT] = tmp.t_quitc;
tty->termios.c_cc[VSTART] = tmp.t_startc;
tty->termios.c_cc[VSTOP] = tmp.t_stopc;
tty->termios.c_cc[VEOF] = tmp.t_eofc;
tty->termios.c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
return 0;
}
#endif
@@ -905,7 +905,7 @@ static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
{
struct ltchars tmp;

- mutex_lock(&tty->termios_mutex);
+ down_read(&tty->termios_rwsem);
tmp.t_suspc = tty->termios.c_cc[VSUSP];
/* what is dsuspc anyway? */
tmp.t_dsuspc = tty->termios.c_cc[VSUSP];
@@ -914,7 +914,7 @@ static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
tmp.t_flushc = tty->termios.c_cc[VEOL2];
tmp.t_werasc = tty->termios.c_cc[VWERASE];
tmp.t_lnextc = tty->termios.c_cc[VLNEXT];
- mutex_unlock(&tty->termios_mutex);
+ up_read(&tty->termios_rwsem);
return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
}

@@ -925,7 +925,7 @@ static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
if (copy_from_user(&tmp, ltchars, sizeof(tmp)))
return -EFAULT;

- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
tty->termios.c_cc[VSUSP] = tmp.t_suspc;
/* what is dsuspc anyway? */
tty->termios.c_cc[VEOL2] = tmp.t_dsuspc;
@@ -934,7 +934,7 @@ static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
tty->termios.c_cc[VEOL2] = tmp.t_flushc;
tty->termios.c_cc[VWERASE] = tmp.t_werasc;
tty->termios.c_cc[VLNEXT] = tmp.t_lnextc;
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
return 0;
}
#endif
@@ -974,7 +974,7 @@ static int send_prio_char(struct tty_struct *tty, char ch)
* @arg: enable/disable CLOCAL
*
* Perform a change to the CLOCAL state and call into the driver
- * layer to make it visible. All done with the termios mutex
+ * layer to make it visible. All done with the termios rwsem
*/

static int tty_change_softcar(struct tty_struct *tty, int arg)
@@ -983,7 +983,7 @@ static int tty_change_softcar(struct tty_struct *tty, int arg)
int bit = arg ? CLOCAL : 0;
struct ktermios old;

- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
old = tty->termios;
tty->termios.c_cflag &= ~CLOCAL;
tty->termios.c_cflag |= bit;
@@ -991,7 +991,7 @@ static int tty_change_softcar(struct tty_struct *tty, int arg)
tty->ops->set_termios(tty, &old);
if ((tty->termios.c_cflag & CLOCAL) != bit)
ret = -EINVAL;
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
return ret;
}

@@ -1094,9 +1094,9 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
if (user_termios_to_kernel_termios(&kterm,
(struct termios __user *) arg))
return -EFAULT;
- mutex_lock(&real_tty->termios_mutex);
+ down_write(&real_tty->termios_rwsem);
real_tty->termios_locked = kterm;
- mutex_unlock(&real_tty->termios_mutex);
+ up_write(&real_tty->termios_rwsem);
return 0;
#else
case TIOCGLCKTRMIOS:
@@ -1111,9 +1111,9 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
if (user_termios_to_kernel_termios_1(&kterm,
(struct termios __user *) arg))
return -EFAULT;
- mutex_lock(&real_tty->termios_mutex);
+ down_write(&real_tty->termios_rwsem);
real_tty->termios_locked = kterm;
- mutex_unlock(&real_tty->termios_mutex);
+ up_write(&real_tty->termios_rwsem);
return ret;
#endif
#ifdef TCGETX
@@ -1121,9 +1121,9 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
struct termiox ktermx;
if (real_tty->termiox == NULL)
return -EINVAL;
- mutex_lock(&real_tty->termios_mutex);
+ down_read(&real_tty->termios_rwsem);
memcpy(&ktermx, real_tty->termiox, sizeof(struct termiox));
- mutex_unlock(&real_tty->termios_mutex);
+ up_read(&real_tty->termios_rwsem);
if (copy_to_user(p, &ktermx, sizeof(struct termiox)))
ret = -EFAULT;
return ret;
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 5a6c43d..d7d5e6a 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -414,14 +414,14 @@ EXPORT_SYMBOL_GPL(tty_ldisc_flush);
* they are not on hot paths so a little discipline won't do
* any harm.
*
- * Locking: takes termios_mutex
+ * Locking: takes termios_rwsem
*/

static void tty_set_termios_ldisc(struct tty_struct *tty, int num)
{
- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
tty->termios.c_line = num;
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
}

/**
@@ -599,11 +599,11 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)

static void tty_reset_termios(struct tty_struct *tty)
{
- mutex_lock(&tty->termios_mutex);
+ down_write(&tty->termios_rwsem);
tty->termios = tty->driver->init_termios;
tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
- mutex_unlock(&tty->termios_mutex);
+ up_write(&tty->termios_rwsem);
}


diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index fbd447b..0829c02 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -829,7 +829,7 @@ static inline int resize_screen(struct vc_data *vc, int width, int height,
* If the caller passes a tty structure then update the termios winsize
* information and perform any necessary signal handling.
*
- * Caller must hold the console semaphore. Takes the termios mutex and
+ * Caller must hold the console semaphore. Takes the termios rwsem and
* ctrl_lock of the tty IFF a tty is passed.
*/

@@ -973,7 +973,7 @@ int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int rows)
* the actual work.
*
* Takes the console sem and the called methods then take the tty
- * termios_mutex and the tty ctrl_lock in that order.
+ * termios_rwsem and the tty ctrl_lock in that order.
*/
static int vt_resize(struct tty_struct *tty, struct winsize *ws)
{
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 7860e52..1d1c7c6a 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -10,6 +10,7 @@
#include <linux/mutex.h>
#include <linux/tty_flags.h>
#include <uapi/linux/tty.h>
+#include <linux/rwsem.h>



@@ -243,9 +244,9 @@ struct tty_struct {

struct mutex atomic_write_lock;
struct mutex legacy_mutex;
- struct mutex termios_mutex;
+ struct rw_semaphore termios_rwsem;
spinlock_t ctrl_lock;
- /* Termios values are protected by the termios mutex */
+ /* Termios values are protected by the termios rwsem */
struct ktermios termios, termios_locked;
struct termiox *termiox; /* May be NULL for unsupported */
char name[64];
@@ -253,7 +254,7 @@ struct tty_struct {
struct pid *session;
unsigned long flags;
int count;
- struct winsize winsize; /* termios mutex */
+ struct winsize winsize; /* termios rwsem */
unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1;
unsigned char warned:1;
unsigned char ctrl_status; /* ctrl_lock */
--
1.8.1.2

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