Commit 04f378b1 authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds

tty: BKL pushdown

- Push the BKL down into the line disciplines
- Switch the tty layer to unlocked_ioctl
- Introduce a new ctrl_lock spin lock for the control bits
- Eliminate much of the lock_kernel use in n_tty
- Prepare to (but don't yet) call the drivers with the lock dropped
  on the paths that historically held the lock

BKL now primarily protects open/close/ldisc change in the tty layer

[jirislaby@gmail.com: a couple of fixes]
Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarJiri Slaby <jirislaby@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e5238442
...@@ -578,26 +578,36 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, ...@@ -578,26 +578,36 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file,
return -EFAULT; return -EFAULT;
} }
lock_kernel();
for (;;) { for (;;) {
if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
unlock_kernel();
return -EIO; return -EIO;
}
n_hdlc = tty2n_hdlc (tty); n_hdlc = tty2n_hdlc (tty);
if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC || if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC ||
tty != n_hdlc->tty) tty != n_hdlc->tty) {
unlock_kernel();
return 0; return 0;
}
rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list); rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
if (rbuf) if (rbuf)
break; break;
/* no data */ /* no data */
if (file->f_flags & O_NONBLOCK) if (file->f_flags & O_NONBLOCK) {
unlock_kernel();
return -EAGAIN; return -EAGAIN;
}
interruptible_sleep_on (&tty->read_wait); interruptible_sleep_on (&tty->read_wait);
if (signal_pending(current)) if (signal_pending(current)) {
unlock_kernel();
return -EINTR; return -EINTR;
}
} }
if (rbuf->count > nr) if (rbuf->count > nr)
...@@ -618,7 +628,7 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, ...@@ -618,7 +628,7 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file,
kfree(rbuf); kfree(rbuf);
else else
n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,rbuf); n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,rbuf);
unlock_kernel();
return ret; return ret;
} /* end of n_hdlc_tty_read() */ } /* end of n_hdlc_tty_read() */
...@@ -661,6 +671,8 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, ...@@ -661,6 +671,8 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file,
count = maxframe; count = maxframe;
} }
lock_kernel();
add_wait_queue(&tty->write_wait, &wait); add_wait_queue(&tty->write_wait, &wait);
set_current_state(TASK_INTERRUPTIBLE); set_current_state(TASK_INTERRUPTIBLE);
...@@ -695,7 +707,7 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, ...@@ -695,7 +707,7 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file,
n_hdlc_buf_put(&n_hdlc->tx_buf_list,tbuf); n_hdlc_buf_put(&n_hdlc->tx_buf_list,tbuf);
n_hdlc_send_frames(n_hdlc,tty); n_hdlc_send_frames(n_hdlc,tty);
} }
unlock_kernel();
return error; return error;
} /* end of n_hdlc_tty_write() */ } /* end of n_hdlc_tty_write() */
......
...@@ -1075,12 +1075,15 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file, ...@@ -1075,12 +1075,15 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
TRACE_L("read()"); TRACE_L("read()");
lock_kernel();
pClient = findClient(pInfo, task_pid(current)); pClient = findClient(pInfo, task_pid(current));
if (pClient) { if (pClient) {
pMsg = remove_msg(pInfo, pClient); pMsg = remove_msg(pInfo, pClient);
if (pMsg == NULL) { if (pMsg == NULL) {
/* no messages available. */ /* no messages available. */
if (file->f_flags & O_NONBLOCK) { if (file->f_flags & O_NONBLOCK) {
unlock_kernel();
return -EAGAIN; return -EAGAIN;
} }
/* block until there is a message: */ /* block until there is a message: */
...@@ -1090,8 +1093,10 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file, ...@@ -1090,8 +1093,10 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
/* If we still haven't got a message, we must have been signalled */ /* If we still haven't got a message, we must have been signalled */
if (!pMsg) if (!pMsg) {
unlock_kernel();
return -EINTR; return -EINTR;
}
/* deliver msg to client process: */ /* deliver msg to client process: */
theMsg.msg_id = pMsg->msg_id; theMsg.msg_id = pMsg->msg_id;
...@@ -1102,12 +1107,15 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file, ...@@ -1102,12 +1107,15 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
kfree(pMsg); kfree(pMsg);
TRACE_M("r3964_read - msg kfree %p", pMsg); TRACE_M("r3964_read - msg kfree %p", pMsg);
if (copy_to_user(buf, &theMsg, count)) if (copy_to_user(buf, &theMsg, count)) {
unlock_kernel();
return -EFAULT; return -EFAULT;
}
TRACE_PS("read - return %d", count); TRACE_PS("read - return %d", count);
return count; return count;
} }
unlock_kernel();
return -EPERM; return -EPERM;
} }
...@@ -1156,6 +1164,8 @@ static ssize_t r3964_write(struct tty_struct *tty, struct file *file, ...@@ -1156,6 +1164,8 @@ static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
pHeader->locks = 0; pHeader->locks = 0;
pHeader->owner = NULL; pHeader->owner = NULL;
lock_kernel();
pClient = findClient(pInfo, task_pid(current)); pClient = findClient(pInfo, task_pid(current));
if (pClient) { if (pClient) {
pHeader->owner = pClient; pHeader->owner = pClient;
...@@ -1173,6 +1183,8 @@ static ssize_t r3964_write(struct tty_struct *tty, struct file *file, ...@@ -1173,6 +1183,8 @@ static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
add_tx_queue(pInfo, pHeader); add_tx_queue(pInfo, pHeader);
trigger_transmit(pInfo); trigger_transmit(pInfo);
unlock_kernel();
return 0; return 0;
} }
......
...@@ -183,22 +183,24 @@ static void reset_buffer_flags(struct tty_struct *tty) ...@@ -183,22 +183,24 @@ static void reset_buffer_flags(struct tty_struct *tty)
* at hangup) or when the N_TTY line discipline internally has to * at hangup) or when the N_TTY line discipline internally has to
* clean the pending queue (for example some signals). * clean the pending queue (for example some signals).
* *
* FIXME: tty->ctrl_status is not spinlocked and relies on * Locking: ctrl_lock
* lock_kernel() still.
*/ */
static void n_tty_flush_buffer(struct tty_struct *tty) static void n_tty_flush_buffer(struct tty_struct *tty)
{ {
unsigned long flags;
/* clear everything and unthrottle the driver */ /* clear everything and unthrottle the driver */
reset_buffer_flags(tty); reset_buffer_flags(tty);
if (!tty->link) if (!tty->link)
return; return;
spin_lock_irqsave(&tty->ctrl_lock, flags);
if (tty->link->packet) { if (tty->link->packet) {
tty->ctrl_status |= TIOCPKT_FLUSHREAD; tty->ctrl_status |= TIOCPKT_FLUSHREAD;
wake_up_interruptible(&tty->link->read_wait); wake_up_interruptible(&tty->link->read_wait);
} }
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
} }
/** /**
...@@ -264,7 +266,7 @@ static inline int is_continuation(unsigned char c, struct tty_struct *tty) ...@@ -264,7 +266,7 @@ static inline int is_continuation(unsigned char c, struct tty_struct *tty)
* relevant in the world today. If you ever need them, add them here. * relevant in the world today. If you ever need them, add them here.
* *
* Called from both the receive and transmit sides and can be called * Called from both the receive and transmit sides and can be called
* re-entrantly. Relies on lock_kernel() still. * re-entrantly. Relies on lock_kernel() for tty->column state.
*/ */
static int opost(unsigned char c, struct tty_struct *tty) static int opost(unsigned char c, struct tty_struct *tty)
...@@ -275,6 +277,7 @@ static int opost(unsigned char c, struct tty_struct *tty) ...@@ -275,6 +277,7 @@ static int opost(unsigned char c, struct tty_struct *tty)
if (!space) if (!space)
return -1; return -1;
lock_kernel();
if (O_OPOST(tty)) { if (O_OPOST(tty)) {
switch (c) { switch (c) {
case '\n': case '\n':
...@@ -323,6 +326,7 @@ static int opost(unsigned char c, struct tty_struct *tty) ...@@ -323,6 +326,7 @@ static int opost(unsigned char c, struct tty_struct *tty)
} }
} }
tty->driver->put_char(tty, c); tty->driver->put_char(tty, c);
unlock_kernel();
return 0; return 0;
} }
...@@ -337,7 +341,8 @@ static int opost(unsigned char c, struct tty_struct *tty) ...@@ -337,7 +341,8 @@ static int opost(unsigned char c, struct tty_struct *tty)
* the simple cases normally found and helps to generate blocks of * the simple cases normally found and helps to generate blocks of
* symbols for the console driver and thus improve performance. * symbols for the console driver and thus improve performance.
* *
* Called from write_chan under the tty layer write lock. * Called from write_chan under the tty layer write lock. Relies
* on lock_kernel for the tty->column state.
*/ */
static ssize_t opost_block(struct tty_struct *tty, static ssize_t opost_block(struct tty_struct *tty,
...@@ -353,6 +358,7 @@ static ssize_t opost_block(struct tty_struct *tty, ...@@ -353,6 +358,7 @@ static ssize_t opost_block(struct tty_struct *tty,
if (nr > space) if (nr > space)
nr = space; nr = space;
lock_kernel();
for (i = 0, cp = buf; i < nr; i++, cp++) { for (i = 0, cp = buf; i < nr; i++, cp++) {
switch (*cp) { switch (*cp) {
case '\n': case '\n':
...@@ -387,6 +393,7 @@ static ssize_t opost_block(struct tty_struct *tty, ...@@ -387,6 +393,7 @@ static ssize_t opost_block(struct tty_struct *tty,
if (tty->driver->flush_chars) if (tty->driver->flush_chars)
tty->driver->flush_chars(tty); tty->driver->flush_chars(tty);
i = tty->driver->write(tty, buf, i); i = tty->driver->write(tty, buf, i);
unlock_kernel();
return i; return i;
} }
...@@ -1194,6 +1201,11 @@ extern ssize_t redirected_tty_write(struct file *, const char __user *, ...@@ -1194,6 +1201,11 @@ extern ssize_t redirected_tty_write(struct file *, const char __user *,
* Perform job control management checks on this file/tty descriptor * Perform job control management checks on this file/tty descriptor
* and if appropriate send any needed signals and return a negative * and if appropriate send any needed signals and return a negative
* error code if action should be taken. * error code if action should be taken.
*
* FIXME:
* Locking: None - redirected write test is safe, testing
* current->signal should possibly lock current->sighand
* pgrp locking ?
*/ */
static int job_control(struct tty_struct *tty, struct file *file) static int job_control(struct tty_struct *tty, struct file *file)
...@@ -1246,6 +1258,7 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file, ...@@ -1246,6 +1258,7 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file,
ssize_t size; ssize_t size;
long timeout; long timeout;
unsigned long flags; unsigned long flags;
int packet;
do_it_again: do_it_again:
...@@ -1289,16 +1302,19 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file, ...@@ -1289,16 +1302,19 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file,
if (mutex_lock_interruptible(&tty->atomic_read_lock)) if (mutex_lock_interruptible(&tty->atomic_read_lock))
return -ERESTARTSYS; return -ERESTARTSYS;
} }
packet = tty->packet;
add_wait_queue(&tty->read_wait, &wait); add_wait_queue(&tty->read_wait, &wait);
while (nr) { while (nr) {
/* First test for status change. */ /* First test for status change. */
if (tty->packet && tty->link->ctrl_status) { if (packet && tty->link->ctrl_status) {
unsigned char cs; unsigned char cs;
if (b != buf) if (b != buf)
break; break;
spin_lock_irqsave(&tty->link->ctrl_lock, flags);
cs = tty->link->ctrl_status; cs = tty->link->ctrl_status;
tty->link->ctrl_status = 0; tty->link->ctrl_status = 0;
spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
if (tty_put_user(tty, cs, b++)) { if (tty_put_user(tty, cs, b++)) {
retval = -EFAULT; retval = -EFAULT;
b--; b--;
...@@ -1333,6 +1349,7 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file, ...@@ -1333,6 +1349,7 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file,
retval = -ERESTARTSYS; retval = -ERESTARTSYS;
break; break;
} }
/* FIXME: does n_tty_set_room need locking ? */
n_tty_set_room(tty); n_tty_set_room(tty);
timeout = schedule_timeout(timeout); timeout = schedule_timeout(timeout);
continue; continue;
...@@ -1340,7 +1357,7 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file, ...@@ -1340,7 +1357,7 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file,
__set_current_state(TASK_RUNNING); __set_current_state(TASK_RUNNING);
/* Deal with packet mode. */ /* Deal with packet mode. */
if (tty->packet && b == buf) { if (packet && b == buf) {
if (tty_put_user(tty, TIOCPKT_DATA, b++)) { if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
retval = -EFAULT; retval = -EFAULT;
b--; b--;
...@@ -1388,6 +1405,8 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file, ...@@ -1388,6 +1405,8 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file,
break; break;
} else { } else {
int uncopied; int uncopied;
/* The copy function takes the read lock and handles
locking internally for this case */
uncopied = copy_from_read_buf(tty, &b, &nr); uncopied = copy_from_read_buf(tty, &b, &nr);
uncopied += copy_from_read_buf(tty, &b, &nr); uncopied += copy_from_read_buf(tty, &b, &nr);
if (uncopied) { if (uncopied) {
...@@ -1429,7 +1448,6 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file, ...@@ -1429,7 +1448,6 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file,
goto do_it_again; goto do_it_again;
n_tty_set_room(tty); n_tty_set_room(tty);
return retval; return retval;
} }
......
...@@ -181,6 +181,7 @@ static int pty_set_lock(struct tty_struct *tty, int __user * arg) ...@@ -181,6 +181,7 @@ static int pty_set_lock(struct tty_struct *tty, int __user * arg)
static void pty_flush_buffer(struct tty_struct *tty) static void pty_flush_buffer(struct tty_struct *tty)
{ {
struct tty_struct *to = tty->link; struct tty_struct *to = tty->link;
unsigned long flags;
if (!to) if (!to)
return; return;
...@@ -189,8 +190,10 @@ static void pty_flush_buffer(struct tty_struct *tty) ...@@ -189,8 +190,10 @@ static void pty_flush_buffer(struct tty_struct *tty)
to->ldisc.flush_buffer(to); to->ldisc.flush_buffer(to);
if (to->packet) { if (to->packet) {
spin_lock_irqsave(&tty->ctrl_lock, flags);
tty->ctrl_status |= TIOCPKT_FLUSHWRITE; tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
wake_up_interruptible(&to->read_wait); wake_up_interruptible(&to->read_wait);
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
} }
} }
......
This diff is collapsed.
...@@ -395,6 +395,7 @@ static void change_termios(struct tty_struct *tty, struct ktermios *new_termios) ...@@ -395,6 +395,7 @@ static void change_termios(struct tty_struct *tty, struct ktermios *new_termios)
int canon_change; int canon_change;
struct ktermios old_termios = *tty->termios; struct ktermios old_termios = *tty->termios;
struct tty_ldisc *ld; struct tty_ldisc *ld;
unsigned long flags;
/* /*
* Perform the actual termios internal changes under lock. * Perform the actual termios internal changes under lock.
...@@ -429,11 +430,13 @@ static void change_termios(struct tty_struct *tty, struct ktermios *new_termios) ...@@ -429,11 +430,13 @@ static void change_termios(struct tty_struct *tty, struct ktermios *new_termios)
STOP_CHAR(tty) == '\023' && STOP_CHAR(tty) == '\023' &&
START_CHAR(tty) == '\021'); START_CHAR(tty) == '\021');
if (old_flow != new_flow) { if (old_flow != new_flow) {
spin_lock_irqsave(&tty->ctrl_lock, flags);
tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP); tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP);
if (new_flow) if (new_flow)
tty->ctrl_status |= TIOCPKT_DOSTOP; tty->ctrl_status |= TIOCPKT_DOSTOP;
else else
tty->ctrl_status |= TIOCPKT_NOSTOP; tty->ctrl_status |= TIOCPKT_NOSTOP;
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
wake_up_interruptible(&tty->link->read_wait); wake_up_interruptible(&tty->link->read_wait);
} }
} }
...@@ -905,6 +908,7 @@ int n_tty_ioctl(struct tty_struct *tty, struct file *file, ...@@ -905,6 +908,7 @@ int n_tty_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg) unsigned int cmd, unsigned long arg)
{ {
struct tty_struct *real_tty; struct tty_struct *real_tty;
unsigned long flags;
int retval; int retval;
if (tty->driver->type == TTY_DRIVER_TYPE_PTY && if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
...@@ -963,6 +967,7 @@ int n_tty_ioctl(struct tty_struct *tty, struct file *file, ...@@ -963,6 +967,7 @@ int n_tty_ioctl(struct tty_struct *tty, struct file *file,
return -ENOTTY; return -ENOTTY;
if (get_user(pktmode, (int __user *) arg)) if (get_user(pktmode, (int __user *) arg))
return -EFAULT; return -EFAULT;
spin_lock_irqsave(&tty->ctrl_lock, flags);
if (pktmode) { if (pktmode) {
if (!tty->packet) { if (!tty->packet) {
tty->packet = 1; tty->packet = 1;
...@@ -970,6 +975,7 @@ int n_tty_ioctl(struct tty_struct *tty, struct file *file, ...@@ -970,6 +975,7 @@ int n_tty_ioctl(struct tty_struct *tty, struct file *file,
} }
} else } else
tty->packet = 0; tty->packet = 0;
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
return 0; return 0;
} }
default: default:
......
...@@ -2541,6 +2541,9 @@ int tioclinux(struct tty_struct *tty, unsigned long arg) ...@@ -2541,6 +2541,9 @@ int tioclinux(struct tty_struct *tty, unsigned long arg)
if (get_user(type, p)) if (get_user(type, p))
return -EFAULT; return -EFAULT;
ret = 0; ret = 0;
lock_kernel();
switch (type) switch (type)
{ {
case TIOCL_SETSEL: case TIOCL_SETSEL:
...@@ -2560,7 +2563,7 @@ int tioclinux(struct tty_struct *tty, unsigned long arg) ...@@ -2560,7 +2563,7 @@ int tioclinux(struct tty_struct *tty, unsigned long arg)
ret = sel_loadlut(p); ret = sel_loadlut(p);
break; break;
case TIOCL_GETSHIFTSTATE: case TIOCL_GETSHIFTSTATE:
/* /*
* Make it possible to react to Shift+Mousebutton. * Make it possible to react to Shift+Mousebutton.
* Note that 'shift_state' is an undocumented * Note that 'shift_state' is an undocumented
...@@ -2615,6 +2618,7 @@ int tioclinux(struct tty_struct *tty, unsigned long arg) ...@@ -2615,6 +2618,7 @@ int tioclinux(struct tty_struct *tty, unsigned long arg)
ret = -EINVAL; ret = -EINVAL;
break; break;
} }
unlock_kernel();
return ret; return ret;
} }
...@@ -3829,7 +3833,7 @@ static int con_font_get(struct vc_data *vc, struct console_font_op *op) ...@@ -3829,7 +3833,7 @@ static int con_font_get(struct vc_data *vc, struct console_font_op *op)
goto out; goto out;
c = (font.width+7)/8 * 32 * font.charcount; c = (font.width+7)/8 * 32 * font.charcount;
if (op->data && font.charcount > op->charcount) if (op->data && font.charcount > op->charcount)
rc = -ENOSPC; rc = -ENOSPC;
if (!(op->flags & KD_FONT_FLAG_OLD)) { if (!(op->flags & KD_FONT_FLAG_OLD)) {
......
...@@ -1046,7 +1046,7 @@ static int vt_check(struct file *file) ...@@ -1046,7 +1046,7 @@ static int vt_check(struct file *file)
struct inode *inode = file->f_path.dentry->d_inode; struct inode *inode = file->f_path.dentry->d_inode;
struct vc_data *vc; struct vc_data *vc;
if (file->f_op->ioctl != tty_ioctl) if (file->f_op->unlocked_ioctl != tty_ioctl)
return -EINVAL; return -EINVAL;
tty = (struct tty_struct *)file->private_data; tty = (struct tty_struct *)file->private_data;
......
...@@ -183,6 +183,7 @@ struct tty_struct { ...@@ -183,6 +183,7 @@ struct tty_struct {
int index; int index;
struct tty_ldisc ldisc; struct tty_ldisc ldisc;
struct mutex termios_mutex; struct mutex termios_mutex;
spinlock_t ctrl_lock;
struct ktermios *termios, *termios_locked; struct ktermios *termios, *termios_locked;
char name[64]; char name[64];
struct pid *pgrp; struct pid *pgrp;
...@@ -323,8 +324,7 @@ extern void tty_ldisc_put(int); ...@@ -323,8 +324,7 @@ extern void tty_ldisc_put(int);
extern void tty_wakeup(struct tty_struct *tty); extern void tty_wakeup(struct tty_struct *tty);
extern void tty_ldisc_flush(struct tty_struct *tty); extern void tty_ldisc_flush(struct tty_struct *tty);
extern int tty_ioctl(struct inode *inode, struct file *file, unsigned int cmd, extern long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
unsigned long arg);
extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file, extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg); unsigned int cmd, unsigned long arg);
extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg); extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
......
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