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, 2 deletions

diff --git a/drivers/char/synclink_gt.c b/drivers/char/synclink_gt.c
index 6473ae023466..1a11717b1adc 100644
--- a/drivers/char/synclink_gt.c
+++ b/drivers/char/synclink_gt.c
@@ -771,8 +771,7 @@ static void close(struct tty_struct *tty, struct file *filp)
 
         if (info->flags & ASYNC_INITIALIZED)
                 wait_until_sent(tty, info->timeout);
-        if (tty->driver->flush_buffer)
-                tty->driver->flush_buffer(tty);
+        flush_buffer(tty);
         tty_ldisc_flush(tty);
 
         shutdown(info);
@@ -967,6 +966,8 @@ static void wait_until_sent(struct tty_struct *tty, int timeout)
          * Note: use tight timings here to satisfy the NIST-PCTS.
          */
 
+        lock_kernel();
+
         if (info->params.data_rate) {
                 char_time = info->timeout/(32 * 5);
                 if (!char_time)
@@ -984,6 +985,7 @@ static void wait_until_sent(struct tty_struct *tty, int timeout)
                 if (timeout && time_after(jiffies, orig_jiffies + timeout))
                         break;
         }
+        unlock_kernel();
 
 exit:
         DBGINFO(("%s wait_until_sent exit\n", info->device_name));