diff options
author | Peter Hurley <peter@hurleysoftware.com> | 2013-06-15 09:14:23 -0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-07-23 16:43:01 -0700 |
commit | 6a1c0680cf3ba94356ecd58833e1540c93472a57 (patch) | |
tree | d370b0888214bb59049181ac98c567d153263f48 | |
parent | a2f73be8ee36e48f11f89ab705beb3c587a2f320 (diff) | |
download | linux-6a1c0680cf3ba94356ecd58833e1540c93472a57.tar.bz2 |
tty: Convert termios_mutex to termios_rwsem
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@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | drivers/net/irda/irtty-sir.c | 8 | ||||
-rw-r--r-- | drivers/tty/n_tty.c | 2 | ||||
-rw-r--r-- | drivers/tty/pty.c | 4 | ||||
-rw-r--r-- | drivers/tty/tty_io.c | 14 | ||||
-rw-r--r-- | drivers/tty/tty_ioctl.c | 90 | ||||
-rw-r--r-- | drivers/tty/tty_ldisc.c | 10 | ||||
-rw-r--r-- | drivers/tty/vt/vt.c | 4 | ||||
-rw-r--r-- | 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 a41267197839..177441afeb96 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 d159059560e8..ab923bb2b262 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -1539,7 +1539,7 @@ 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 abfd99089781..1b39dd639ee9 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -287,7 +287,7 @@ 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; @@ -314,7 +314,7 @@ 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 0fa5db4c7a7a..639e24ade9bf 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -604,7 +604,7 @@ static int tty_signal_session_leader(struct tty_struct *tty, int exit_session) * redirect lock for undoing redirection * file list lock for manipulating list of ttys * tty_ldiscs_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 */ @@ -2230,7 +2230,7 @@ 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. */ @@ -2238,9 +2238,9 @@ 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; } @@ -2261,7 +2261,7 @@ 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 @@ -2276,7 +2276,7 @@ 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); @@ -3015,7 +3015,7 @@ 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 3500d4114147..9ce20df8a2c8 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. */ @@ -528,7 +528,7 @@ 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) @@ -544,7 +544,7 @@ 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); @@ -586,7 +586,7 @@ 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); @@ -601,7 +601,7 @@ 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) @@ -613,9 +613,9 @@ 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, @@ -667,16 +667,16 @@ 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) @@ -723,10 +723,10 @@ 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; } @@ -761,13 +761,13 @@ 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; } @@ -806,7 +806,7 @@ 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) @@ -822,7 +822,7 @@ 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; @@ -832,7 +832,7 @@ 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; } @@ -843,14 +843,14 @@ 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; } @@ -860,14 +860,14 @@ 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 @@ -877,7 +877,7 @@ 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]; @@ -886,7 +886,7 @@ 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; } @@ -897,7 +897,7 @@ 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; @@ -906,7 +906,7 @@ 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 @@ -946,7 +946,7 @@ 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) @@ -955,7 +955,7 @@ 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; @@ -963,7 +963,7 @@ 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; } @@ -1066,9 +1066,9 @@ 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: @@ -1083,9 +1083,9 @@ 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 @@ -1093,9 +1093,9 @@ 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 e52d61573553..6458e11e8e9d 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -415,14 +415,14 @@ 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); } /** @@ -602,11 +602,11 @@ 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 c677829baa8b..02af6ccefe6a 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -828,7 +828,7 @@ 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. */ @@ -972,7 +972,7 @@ 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 8323ee4f95b9..d3042076d163 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 ctrl_status; /* ctrl_lock */ unsigned int receive_room; /* Bytes free for queue */ |