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tty: The big operations rework

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- Operations are now a shared const function block as with most other Linux
  objects

- Introduce wrappers for some optional functions to get consistent behaviour

- Wrap put_char which used to be patched by the tty layer

- Document which functions are needed/optional

- Make put_char report success/fail

- Cache the driver->ops pointer in the tty as tty->ops

- Remove various surplus lock calls we no longer need

- Remove proc_write method as noted by Alexey Dobriyan

- Introduce some missing sanity checks where certain driver/ldisc
  combinations would oops as they didn't check needed methods were present

[akpm@linux-foundation.org: fix fs/compat_ioctl.c build]
[akpm@linux-foundation.org: fix isicom]
[akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build]
[akpm@linux-foundation.org: fix kgdb]
Signed-off-by: Alan Cox <alan@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alan Cox
2008-04-30 00:54:13 -07:00
committed by Linus Torvalds
parent 251b8dd7ee
commit f34d7a5b70
30 changed files with 539 additions and 666 deletions
Download Patch File Download Diff File Expand all files Collapse all files

174
drivers/char/tty_io.c
View File

@ -1108,8 +1108,8 @@ restart:
a reference to the old ldisc. If we ended up flipping back
to the existing ldisc we have two references to it */
if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc)
tty->driver->set_ldisc(tty);
if (tty->ldisc.num != o_ldisc.num && tty->ops->set_ldisc)
tty->ops->set_ldisc(tty);
tty_ldisc_put(o_ldisc.num);
@ -1181,9 +1181,8 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line)
if (*str == '\0')
str = NULL;
if (tty_line >= 0 && tty_line <= p->num && p->poll_init &&
!p->poll_init(p, tty_line, str)) {
if (tty_line >= 0 && tty_line <= p->num && p->ops &&
p->ops->poll_init && !p->ops->poll_init(p, tty_line, str)) {
res = p;
*line = tty_line;
break;
@ -1452,8 +1451,7 @@ static void do_tty_hangup(struct work_struct *work)
/* We may have no line discipline at this point */
if (ld->flush_buffer)
ld->flush_buffer(tty);
if (tty->driver->flush_buffer)
tty->driver->flush_buffer(tty);
tty_driver_flush_buffer(tty);
if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
ld->write_wakeup)
ld->write_wakeup(tty);
@ -1516,11 +1514,11 @@ static void do_tty_hangup(struct work_struct *work)
* So we just call close() the right number of times.
*/
if (cons_filp) {
if (tty->driver->close)
if (tty->ops->close)
for (n = 0; n < closecount; n++)
tty->driver->close(tty, cons_filp);
} else if (tty->driver->hangup)
(tty->driver->hangup)(tty);
tty->ops->close(tty, cons_filp);
} else if (tty->ops->hangup)
(tty->ops->hangup)(tty);
/*
* We don't want to have driver/ldisc interactions beyond
* the ones we did here. The driver layer expects no
@ -1752,8 +1750,8 @@ void stop_tty(struct tty_struct *tty)
wake_up_interruptible(&tty->link->read_wait);
}
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
if (tty->driver->stop)
(tty->driver->stop)(tty);
if (tty->ops->stop)
(tty->ops->stop)(tty);
}
EXPORT_SYMBOL(stop_tty);
@ -1786,8 +1784,8 @@ void start_tty(struct tty_struct *tty)
wake_up_interruptible(&tty->link->read_wait);
}
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
if (tty->driver->start)
(tty->driver->start)(tty);
if (tty->ops->start)
(tty->ops->start)(tty);
/* If we have a running line discipline it may need kicking */
tty_wakeup(tty);
}
@ -1972,10 +1970,13 @@ static ssize_t tty_write(struct file *file, const char __user *buf,
tty = (struct tty_struct *)file->private_data;
if (tty_paranoia_check(tty, inode, "tty_write"))
return -EIO;
if (!tty || !tty->driver->write ||
if (!tty || !tty->ops->write ||
(test_bit(TTY_IO_ERROR, &tty->flags)))
return -EIO;
/* Short term debug to catch buggy drivers */
if (tty->ops->write_room == NULL)
printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
tty->driver->name);
ld = tty_ldisc_ref_wait(tty);
if (!ld->write)
ret = -EIO;
@ -2122,6 +2123,7 @@ static int init_dev(struct tty_driver *driver, int idx,
goto fail_no_mem;
initialize_tty_struct(tty);
tty->driver = driver;
tty->ops = driver->ops;
tty->index = idx;
tty_line_name(driver, idx, tty->name);
@ -2152,6 +2154,7 @@ static int init_dev(struct tty_driver *driver, int idx,
goto free_mem_out;
initialize_tty_struct(o_tty);
o_tty->driver = driver->other;
o_tty->ops = driver->ops;
o_tty->index = idx;
tty_line_name(driver->other, idx, o_tty->name);
@ -2456,8 +2459,8 @@ static void release_dev(struct file *filp)
}
}
#endif
if (tty->driver->close)
tty->driver->close(tty, filp);
if (tty->ops->close)
tty->ops->close(tty, filp);
/*
* Sanity check: if tty->count is going to zero, there shouldn't be
@ -2740,8 +2743,8 @@ got_driver:
printk(KERN_DEBUG "opening %s...", tty->name);
#endif
if (!retval) {
if (tty->driver->open)
retval = tty->driver->open(tty, filp);
if (tty->ops->open)
retval = tty->ops->open(tty, filp);
else
retval = -ENODEV;
}
@ -2840,7 +2843,7 @@ static int ptmx_open(struct inode *inode, struct file *filp)
goto out1;
check_tty_count(tty, "tty_open");
retval = ptm_driver->open(tty, filp);
retval = ptm_driver->ops->open(tty, filp);
if (!retval)
return 0;
out1:
@ -3336,25 +3339,20 @@ static int tiocsetd(struct tty_struct *tty, int __user *p)
static int send_break(struct tty_struct *tty, unsigned int duration)
{
int retval = -EINTR;
lock_kernel();
if (tty_write_lock(tty, 0) < 0)
goto out;
tty->driver->break_ctl(tty, -1);
return -EINTR;
tty->ops->break_ctl(tty, -1);
if (!signal_pending(current))
msleep_interruptible(duration);
tty->driver->break_ctl(tty, 0);
tty->ops->break_ctl(tty, 0);
tty_write_unlock(tty);
if (!signal_pending(current))
retval = 0;
out:
unlock_kernel();
return retval;
return -EINTR;
return 0;
}
/**
* tiocmget - get modem status
* tty_tiocmget - get modem status
* @tty: tty device
* @file: user file pointer
* @p: pointer to result
@ -3369,10 +3367,8 @@ static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p
{
int retval = -EINVAL;
if (tty->driver->tiocmget) {
lock_kernel();
retval = tty->driver->tiocmget(tty, file);
unlock_kernel();
if (tty->ops->tiocmget) {
retval = tty->ops->tiocmget(tty, file);
if (retval >= 0)
retval = put_user(retval, p);
@ -3381,7 +3377,7 @@ static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p
}
/**
* tiocmset - set modem status
* tty_tiocmset - set modem status
* @tty: tty device
* @file: user file pointer
* @cmd: command - clear bits, set bits or set all
@ -3398,7 +3394,7 @@ static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int
{
int retval = -EINVAL;
if (tty->driver->tiocmset) {
if (tty->ops->tiocmset) {
unsigned int set, clear, val;
retval = get_user(val, p);
@ -3422,9 +3418,7 @@ static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int
set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
lock_kernel();
retval = tty->driver->tiocmset(tty, file, set, clear);
unlock_kernel();
retval = tty->ops->tiocmset(tty, file, set, clear);
}
return retval;
}
@ -3455,23 +3449,25 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
retval = -EINVAL;
if (!tty->driver->break_ctl) {
if (!tty->ops->break_ctl) {
switch (cmd) {
case TIOCSBRK:
case TIOCCBRK:
if (tty->driver->ioctl)
retval = tty->driver->ioctl(tty, file, cmd, arg);
if (tty->ops->ioctl)
retval = tty->ops->ioctl(tty, file, cmd, arg);
if (retval != -EINVAL && retval != -ENOIOCTLCMD)
printk(KERN_WARNING "tty: driver %s needs updating to use break_ctl\n", tty->driver->name);
return retval;
/* These two ioctl's always return success; even if */
/* the driver doesn't support them. */
case TCSBRK:
case TCSBRKP:
if (!tty->driver->ioctl)
if (!tty->ops->ioctl)
return 0;
lock_kernel();
retval = tty->driver->ioctl(tty, file, cmd, arg);
unlock_kernel();
retval = tty->ops->ioctl(tty, file, cmd, arg);
if (retval != -EINVAL && retval != -ENOIOCTLCMD)
printk(KERN_WARNING "tty: driver %s needs updating to use break_ctl\n", tty->driver->name);
if (retval == -ENOIOCTLCMD)
retval = 0;
return retval;
@ -3491,9 +3487,7 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
if (retval)
return retval;
if (cmd != TIOCCBRK) {
lock_kernel();
tty_wait_until_sent(tty, 0);
unlock_kernel();
if (signal_pending(current))
return -EINTR;
}
@ -3531,7 +3525,6 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case TIOCGSID:
return tiocgsid(tty, real_tty, p);
case TIOCGETD:
/* FIXME: check this is ok */
return put_user(tty->ldisc.num, (int __user *)p);
case TIOCSETD:
return tiocsetd(tty, p);
@ -3543,15 +3536,13 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
* Break handling
*/
case TIOCSBRK: /* Turn break on, unconditionally */
lock_kernel();
tty->driver->break_ctl(tty, -1);
unlock_kernel();
if (tty->ops->break_ctl)
tty->ops->break_ctl(tty, -1);
return 0;
case TIOCCBRK: /* Turn break off, unconditionally */
lock_kernel();
tty->driver->break_ctl(tty, 0);
unlock_kernel();
if (tty->ops->break_ctl)
tty->ops->break_ctl(tty, 0);
return 0;
case TCSBRK: /* SVID version: non-zero arg --> no break */
/* non-zero arg means wait for all output data
@ -3580,8 +3571,8 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
}
break;
}
if (tty->driver->ioctl) {
retval = (tty->driver->ioctl)(tty, file, cmd, arg);
if (tty->ops->ioctl) {
retval = (tty->ops->ioctl)(tty, file, cmd, arg);
if (retval != -ENOIOCTLCMD)
return retval;
}
@ -3608,8 +3599,8 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd,
if (tty_paranoia_check(tty, inode, "tty_ioctl"))
return -EINVAL;
if (tty->driver->compat_ioctl) {
retval = (tty->driver->compat_ioctl)(tty, file, cmd, arg);
if (tty->ops->compat_ioctl) {
retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
if (retval != -ENOIOCTLCMD)
return retval;
}
@ -3659,8 +3650,7 @@ void __do_SAK(struct tty_struct *tty)
tty_ldisc_flush(tty);
if (tty->driver->flush_buffer)
tty->driver->flush_buffer(tty);
tty_driver_flush_buffer(tty);
read_lock(&tasklist_lock);
/* Kill the entire session */
@ -3871,15 +3861,27 @@ static void initialize_tty_struct(struct tty_struct *tty)
INIT_WORK(&tty->SAK_work, do_SAK_work);
}
/*
* The default put_char routine if the driver did not define one.
/**
* tty_put_char - write one character to a tty
* @tty: tty
* @ch: character
*
* Write one byte to the tty using the provided put_char method
* if present. Returns the number of characters successfully output.
*
* Note: the specific put_char operation in the driver layer may go
* away soon. Don't call it directly, use this method
*/
static void tty_default_put_char(struct tty_struct *tty, unsigned char ch)
int tty_put_char(struct tty_struct *tty, unsigned char ch)
{
tty->driver->write(tty, &ch, 1);
if (tty->ops->put_char)
return tty->ops->put_char(tty, ch);
return tty->ops->write(tty, &ch, 1);
}
EXPORT_SYMBOL_GPL(tty_put_char);
static struct class *tty_class;
/**
@ -3962,37 +3964,8 @@ void put_tty_driver(struct tty_driver *driver)
void tty_set_operations(struct tty_driver *driver,
const struct tty_operations *op)
{
driver->open = op->open;
driver->close = op->close;
driver->write = op->write;
driver->put_char = op->put_char;
driver->flush_chars = op->flush_chars;
driver->write_room = op->write_room;
driver->chars_in_buffer = op->chars_in_buffer;
driver->ioctl = op->ioctl;
driver->compat_ioctl = op->compat_ioctl;
driver->set_termios = op->set_termios;
driver->throttle = op->throttle;
driver->unthrottle = op->unthrottle;
driver->stop = op->stop;
driver->start = op->start;
driver->hangup = op->hangup;
driver->break_ctl = op->break_ctl;
driver->flush_buffer = op->flush_buffer;
driver->set_ldisc = op->set_ldisc;
driver->wait_until_sent = op->wait_until_sent;
driver->send_xchar = op->send_xchar;
driver->read_proc = op->read_proc;
driver->write_proc = op->write_proc;
driver->tiocmget = op->tiocmget;
driver->tiocmset = op->tiocmset;
#ifdef CONFIG_CONSOLE_POLL
driver->poll_init = op->poll_init;
driver->poll_get_char = op->poll_get_char;
driver->poll_put_char = op->poll_put_char;
#endif
}
driver->ops = op;
};
EXPORT_SYMBOL(alloc_tty_driver);
EXPORT_SYMBOL(put_tty_driver);
@ -4055,9 +4028,6 @@ int tty_register_driver(struct tty_driver *driver)
return error;
}
if (!driver->put_char)
driver->put_char = tty_default_put_char;
mutex_lock(&tty_mutex);
list_add(&driver->tty_drivers, &tty_drivers);
mutex_unlock(&tty_mutex);