Move the inline code for waking up writers to a new function

ttwwakeup().  The conditions for doing the wakeup will soon become
more complicated and I don't want them duplicated in all drivers.

It's probably not worth making ttwwakeup() a macro or an inline
function.  The cost of the function call is relatively small when
there is a process to wake up.  There is usually a process to wake
up for large writes and the system call overhead dwarfs the function
call overhead for small writes.

1 files changed, 18 insertions, 1 deletions

diff --git a/sys/kern/tty.c b/sys/kern/tty.c
index 8efe14b..9802f10 100644
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)tty.c	8.8 (Berkeley) 1/21/94
- * $Id: tty.c,v 1.54 1995/07/21 20:52:38 bde Exp $
+ * $Id: tty.c,v 1.55 1995/07/21 22:51:50 bde Exp $
  */
 
 /*-
@@ -2054,6 +2054,23 @@ ttwakeup(tp)
 }
 
 /*
+ * Wake up any writers on a tty.
+ */
+void
+ttwwakeup(tp)
+	register struct tty *tp;
+{
+
+	if (tp->t_outq.c_cc <= tp->t_lowat) {
+		if (tp->t_state & TS_ASLEEP) {
+			tp->t_state &= ~TS_ASLEEP;
+			wakeup(&tp->t_outq);
+		}
+		selwakeup(&tp->t_wsel);
+	}
+}
+
+/*
  * Look up a code for a specified speed in a conversion table;
  * used by drivers to map software speed values to hardware parameters.
  */