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, 17 insertions, 18 deletions

diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index a69e4bb91ad4..6812fda20953 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -1012,6 +1012,22 @@ static void isicom_shutdown_port(struct isi_port *port)
         }
 }
 
+static void isicom_flush_buffer(struct tty_struct *tty)
+{
+        struct isi_port *port = tty->driver_data;
+        struct isi_board *card = port->card;
+        unsigned long flags;
+
+        if (isicom_paranoia_check(port, tty->name, "isicom_flush_buffer"))
+                return;
+
+        spin_lock_irqsave(&card->card_lock, flags);
+        port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
+        spin_unlock_irqrestore(&card->card_lock, flags);
+
+        tty_wakeup(tty);
+}
+
 static void isicom_close(struct tty_struct *tty, struct file *filp)
 {
         struct isi_port *port = tty->driver_data;
@@ -1065,8 +1081,7 @@ static void isicom_close(struct tty_struct *tty, struct file *filp)
         isicom_shutdown_port(port);
         spin_unlock_irqrestore(&card->card_lock, flags);
 
-        if (tty->driver->flush_buffer)
-                tty->driver->flush_buffer(tty);
+        isicom_flush_buffer(tty);
         tty_ldisc_flush(tty);
 
         spin_lock_irqsave(&card->card_lock, flags);
@@ -1447,22 +1462,6 @@ static void isicom_hangup(struct tty_struct *tty)
         wake_up_interruptible(&port->open_wait);
 }
 
-/* flush_buffer et all */
-static void isicom_flush_buffer(struct tty_struct *tty)
-{
-        struct isi_port *port = tty->driver_data;
-        struct isi_board *card = port->card;
-        unsigned long flags;
-
-        if (isicom_paranoia_check(port, tty->name, "isicom_flush_buffer"))
-                return;
-
-        spin_lock_irqsave(&card->card_lock, flags);
-        port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
-        spin_unlock_irqrestore(&card->card_lock, flags);
-
-        tty_wakeup(tty);
-}
 
 /*
  * Driver init and deinit functions