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_ioctl.c b/drivers/char/tty_ioctl.c
index 8c4bf3e..c10d40c 100644
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -40,6 +40,34 @@
#define TERMIOS_OLD 8
+int tty_chars_in_buffer(struct tty_struct *tty)
+{
+ if (tty->ops->chars_in_buffer)
+ return tty->ops->chars_in_buffer(tty);
+ else
+ return 0;
+}
+
+EXPORT_SYMBOL(tty_chars_in_buffer);
+
+int tty_write_room(struct tty_struct *tty)
+{
+ if (tty->ops->write_room)
+ return tty->ops->write_room(tty);
+ return 2048;
+}
+
+EXPORT_SYMBOL(tty_write_room);
+
+void tty_driver_flush_buffer(struct tty_struct *tty)
+{
+ if (tty->ops->flush_buffer)
+ tty->ops->flush_buffer(tty);
+}
+
+EXPORT_SYMBOL(tty_driver_flush_buffer);
+
+
/**
* tty_wait_until_sent - wait for I/O to finish
* @tty: tty we are waiting for
@@ -58,17 +86,13 @@
printk(KERN_DEBUG "%s wait until sent...\n", tty_name(tty, buf));
#endif
- if (!tty->driver->chars_in_buffer)
- return;
if (!timeout)
timeout = MAX_SCHEDULE_TIMEOUT;
- lock_kernel();
if (wait_event_interruptible_timeout(tty->write_wait,
- !tty->driver->chars_in_buffer(tty), timeout) >= 0) {
- if (tty->driver->wait_until_sent)
- tty->driver->wait_until_sent(tty, timeout);
+ !tty_chars_in_buffer(tty), timeout) >= 0) {
+ if (tty->ops->wait_until_sent)
+ tty->ops->wait_until_sent(tty, timeout);
}
- unlock_kernel();
}
EXPORT_SYMBOL(tty_wait_until_sent);
@@ -444,8 +468,8 @@
}
}
- if (tty->driver->set_termios)
- (*tty->driver->set_termios)(tty, &old_termios);
+ if (tty->ops->set_termios)
+ (*tty->ops->set_termios)(tty, &old_termios);
else
tty_termios_copy_hw(tty->termios, &old_termios);
@@ -748,8 +772,8 @@
{
int was_stopped = tty->stopped;
- if (tty->driver->send_xchar) {
- tty->driver->send_xchar(tty, ch);
+ if (tty->ops->send_xchar) {
+ tty->ops->send_xchar(tty, ch);
return 0;
}
@@ -758,7 +782,7 @@
if (was_stopped)
start_tty(tty);
- tty->driver->write(tty, &ch, 1);
+ tty->ops->write(tty, &ch, 1);
if (was_stopped)
stop_tty(tty);
tty_write_unlock(tty);
@@ -778,13 +802,14 @@
{
int ret = 0;
int bit = arg ? CLOCAL : 0;
- struct ktermios old = *tty->termios;
+ struct ktermios old;
mutex_lock(&tty->termios_mutex);
+ old = *tty->termios;
tty->termios->c_cflag &= ~CLOCAL;
tty->termios->c_cflag |= bit;
- if (tty->driver->set_termios)
- tty->driver->set_termios(tty, &old);
+ if (tty->ops->set_termios)
+ tty->ops->set_termios(tty, &old);
if ((tty->termios->c_cflag & CLOCAL) != bit)
ret = -EINVAL;
mutex_unlock(&tty->termios_mutex);
@@ -926,8 +951,7 @@
ld->flush_buffer(tty);
/* fall through */
case TCOFLUSH:
- if (tty->driver->flush_buffer)
- tty->driver->flush_buffer(tty);
+ tty_driver_flush_buffer(tty);
break;
default:
tty_ldisc_deref(ld);
@@ -984,9 +1008,7 @@
case TCFLSH:
return tty_perform_flush(tty, arg);
case TIOCOUTQ:
- return put_user(tty->driver->chars_in_buffer ?
- tty->driver->chars_in_buffer(tty) : 0,
- (int __user *) arg);
+ return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
case TIOCINQ:
retval = tty->read_cnt;
if (L_ICANON(tty))