tty/serial: lay the foundations for the next set of reworks

- Stop drivers calling their own flush method indirectly, it obfuscates code
  and it will change soon anyway

- A few more lock_kernel paths temporarily needed in some driver internal
  waiting code

- Remove private put_char method that does a write call for one char - we
  have that anyway

- Most but not yet all of the termios copy under lock fixing (some has other
  dependencies to follow)

- Note a few locking bugs in drivers found in the process

- Kill remaining [ab]users of TIOCG/SSOFTCAR in the driver, these must go to
  fix the termios locking

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 22 insertions, 24 deletions

diff --git a/drivers/char/specialix.c b/drivers/char/specialix.c
index 9f9a4bdc1b0e..075ad924dd04 100644
--- a/drivers/char/specialix.c
+++ b/drivers/char/specialix.c
@@ -1504,6 +1504,27 @@ static int sx_open(struct tty_struct * tty, struct file * filp)
         return 0;
 }
 
+static void sx_flush_buffer(struct tty_struct *tty)
+{
+        struct specialix_port *port = (struct specialix_port *)tty->driver_data;
+        unsigned long flags;
+        struct specialix_board  * bp;
+
+        func_enter();
+
+        if (sx_paranoia_check(port, tty->name, "sx_flush_buffer")) {
+                func_exit();
+                return;
+        }
+
+        bp = port_Board(port);
+        spin_lock_irqsave(&port->lock, flags);
+        port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
+        spin_unlock_irqrestore(&port->lock, flags);
+        tty_wakeup(tty);
+
+        func_exit();
+}
 
 static void sx_close(struct tty_struct * tty, struct file * filp)
 {
@@ -1597,8 +1618,7 @@ static void sx_close(struct tty_struct * tty, struct file * filp)
         }
 
         sx_shutdown_port(bp, port);
-        if (tty->driver->flush_buffer)
-                tty->driver->flush_buffer(tty);
+        sx_flush_buffer(tty);
         tty_ldisc_flush(tty);
         spin_lock_irqsave(&port->lock, flags);
         tty->closing = 0;
@@ -1770,28 +1790,6 @@ static int sx_chars_in_buffer(struct tty_struct *tty)
 }
 
 
-static void sx_flush_buffer(struct tty_struct *tty)
-{
-        struct specialix_port *port = (struct specialix_port *)tty->driver_data;
-        unsigned long flags;
-        struct specialix_board  * bp;
-
-        func_enter();
-
-        if (sx_paranoia_check(port, tty->name, "sx_flush_buffer")) {
-                func_exit();
-                return;
-        }
-
-        bp = port_Board(port);
-        spin_lock_irqsave(&port->lock, flags);
-        port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
-        spin_unlock_irqrestore(&port->lock, flags);
-        tty_wakeup(tty);
-
-        func_exit();
-}
-
 
 static int sx_tiocmget(struct tty_struct *tty, struct file *file)
 {