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, 4 insertions, 14 deletions

diff --git a/drivers/serial/mcfserial.c b/drivers/serial/mcfserial.c
index ddd3aa50d4ad..aafa1704e1ab 100644
--- a/drivers/serial/mcfserial.c
+++ b/drivers/serial/mcfserial.c
@@ -1072,18 +1072,6 @@ static int mcfrs_ioctl(struct tty_struct *tty, struct file * file,
                         tty_wait_until_sent(tty, 0);
                         send_break(info, arg ? arg*(HZ/10) : HZ/4);
                         return 0;
-                case TIOCGSOFTCAR:
-                        error = put_user(C_CLOCAL(tty) ? 1 : 0,
-                                    (unsigned long *) arg);
-                        if (error)
-                                return error;
-                        return 0;
-                case TIOCSSOFTCAR:
-                        get_user(arg, (unsigned long *) arg);
-                        tty->termios->c_cflag =
-                                ((tty->termios->c_cflag & ~CLOCAL) |
-                                 (arg ? CLOCAL : 0));
-                        return 0;
                 case TIOCGSERIAL:
                         if (access_ok(VERIFY_WRITE, (void *) arg,
                                                 sizeof(struct serial_struct)))
@@ -1222,8 +1210,7 @@ static void mcfrs_close(struct tty_struct *tty, struct file * filp)
         } else
 #endif
         shutdown(info);
-        if (tty->driver->flush_buffer)
-                tty->driver->flush_buffer(tty);
+        mcfrs_flush_buffer(tty);
         tty_ldisc_flush(tty);
         
         tty->closing = 0;
@@ -1276,6 +1263,8 @@ mcfrs_wait_until_sent(struct tty_struct *tty, int timeout)
          * Note: we have to use pretty tight timings here to satisfy
          * the NIST-PCTS.
          */
+        lock_kernel();
+
         fifo_time = (MCF5272_FIFO_SIZE * HZ * 10) / info->baud;
         char_time = fifo_time / 5;
         if (char_time == 0)
@@ -1312,6 +1301,7 @@ mcfrs_wait_until_sent(struct tty_struct *tty, int timeout)
                 if (timeout && time_after(jiffies, orig_jiffies + timeout))
                         break;
         }
+        unlock_kernel();
 #else
         /*
          * For the other coldfire models, assume all data has been sent