[PATCH] tty buffering stall fix

Prevent stalled processing of received data when a driver allocates tty
buffer space but does not immediately follow the allocation with more data
and a call to schedule receive tty processing.  (example: hvc_console) This
bug was introduced by the first locking patch for the new tty buffering.

Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/tty_flip.h b/include/linux/tty_flip.h
index 82961eb19888..222faf97d5f9 100644
--- a/include/linux/tty_flip.h
+++ b/include/linux/tty_flip.h
@@ -29,8 +29,10 @@ _INLINE_ void tty_schedule_flip(struct tty_struct *tty)
 {
         unsigned long flags;
         spin_lock_irqsave(&tty->buf.lock, flags);
-        if (tty->buf.tail != NULL)
+        if (tty->buf.tail != NULL) {
                 tty->buf.tail->active = 0;
+                tty->buf.tail->commit = tty->buf.tail->used;
+        }
         spin_unlock_irqrestore(&tty->buf.lock, flags);
         schedule_delayed_work(&tty->buf.work, 1);
 }