[src/trunk]: src/sys/dev/usb Don't rely on TS_BUSY to determine wether there ...

[mlelstv <mlelstv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3e13c4c0e5dc
branches:  trunk
changeset: 782119:3e13c4c0e5dc
user:      mlelstv <mlelstv%NetBSD.org@localhost>
date:      Wed Oct 17 17:05:15 2012 +0000

description:
Don't rely on TS_BUSY to determine wether there is a buffer
available. Instead handle a possible buffer shortage.
Also aquire lock when modifying t_state.

diffstat:

 sys/dev/usb/ucom.c |  11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)

diffs (44 lines):

diff -r 2830ec64b257 -r 3e13c4c0e5dc sys/dev/usb/ucom.c
--- a/sys/dev/usb/ucom.c        Wed Oct 17 16:16:23 2012 +0000
+++ b/sys/dev/usb/ucom.c        Wed Oct 17 17:05:15 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ucom.c,v 1.99 2012/03/06 03:35:29 mrg Exp $    */
+/*     $NetBSD: ucom.c,v 1.100 2012/10/17 17:05:15 mlelstv Exp $       */
 
 /*
  * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ucom.c,v 1.99 2012/03/06 03:35:29 mrg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ucom.c,v 1.100 2012/10/17 17:05:15 mlelstv Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1002,7 +1002,10 @@
                goto out;
 
        ub = SIMPLEQ_FIRST(&sc->sc_obuff_free);
-       KASSERT(ub != NULL);
+       if (ub == NULL) {
+               SET(tp->t_state, TS_BUSY);
+               goto out;
+       }
        SIMPLEQ_REMOVE_HEAD(&sc->sc_obuff_free, ub_link);
 
        if (SIMPLEQ_FIRST(&sc->sc_obuff_free) == NULL)
@@ -1070,11 +1073,13 @@
                SIMPLEQ_INSERT_TAIL(&sc->sc_obuff_free, ub, ub_link);
                cc -= sc->sc_opkthdrlen;
 
+               mutex_spin_enter(&tty_lock);
                CLR(tp->t_state, TS_BUSY);
                if (ISSET(tp->t_state, TS_FLUSH))
                        CLR(tp->t_state, TS_FLUSH);
                else
                        ndflush(&tp->t_outq, cc);
+               mutex_spin_exit(&tty_lock);
 
                if (err != USBD_CANCELLED && err != USBD_IOERROR &&
                    !sc->sc_dying) {