tty: The big operations rework
- 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>
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index b1692af..f69fb8d 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1108,8 +1108,8 @@
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 @@
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 @@
/* 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 @@
* 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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
}
}
#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 @@
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 @@
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 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 @@
{
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 @@
}
/**
- * 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 @@
{
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 @@
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 @@
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 @@
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 @@
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 @@
* 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 @@
}
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 @@
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 @@
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 @@
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 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 @@
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);