[TTY]: Fix network driver interactions with TCGET/SET calls.

Dave Miller noted various cases where line disciplines for things like
ppp go poking around in termios themselves in ways that broke with the
new termios code. Rather than have them all learning about termios
internals provide proper methods for this

- tty_mode_ioctl()

	This handles all the terminal mode handling for speed/carrier
etc and none of the methods are ldisc dependant so they can be called
by any user

- tty_perform_flush()

	This extracts the flush functionality and enables pppd the ppp
layer to share it cleanly.

The existing n_tty_ioctl code is refactored in this patch to provide
the new functions and to call them itself appropriately. This patch
has no (intended) behaviour changes and simply prepares for the other
fixes.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/tty.h b/include/linux/tty.h
index 56164d7ba0ad..c555f5442bd7 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -332,7 +332,9 @@ extern void tty_ldisc_flush(struct tty_struct *tty);
 
 extern int tty_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 		     unsigned long arg);
-
+extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
+			unsigned int cmd, unsigned long arg);
+extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
 extern dev_t tty_devnum(struct tty_struct *tty);
 extern void proc_clear_tty(struct task_struct *p);
 extern struct tty_struct *get_current_tty(void);