[src/trunk]: src/sys/kern Fix locking when collecting pt_read and pt_ucntl.

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

details:   https://anonhg.NetBSD.org/src/rev/5163717be3a4
branches:  trunk
changeset: 748040:5163717be3a4
user:      dsl <dsl%NetBSD.org@localhost>
date:      Sun Oct 11 08:08:32 2009 +0000

description:
Fix locking when collecting pt_read and pt_ucntl.

diffstat:

 sys/kern/tty_pty.c |  17 +++++++++--------
 1 files changed, 9 insertions(+), 8 deletions(-)

diffs (58 lines):

diff -r e674ec132e8f -r 5163717be3a4 sys/kern/tty_pty.c
--- a/sys/kern/tty_pty.c        Sun Oct 11 07:09:39 2009 +0000
+++ b/sys/kern/tty_pty.c        Sun Oct 11 08:08:32 2009 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tty_pty.c,v 1.117 2009/06/12 09:26:50 plunky Exp $     */
+/*     $NetBSD: tty_pty.c,v 1.118 2009/10/11 08:08:32 dsl Exp $        */
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -37,7 +37,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tty_pty.c,v 1.117 2009/06/12 09:26:50 plunky Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tty_pty.c,v 1.118 2009/10/11 08:08:32 dsl Exp $");
 
 #include "opt_ptm.h"
 
@@ -584,6 +584,7 @@
        struct tty *tp = pti->pt_tty;
        u_char bf[BUFSIZ];
        int error = 0, cc;
+       int c;
 
        /*
         * We want to block until the slave
@@ -594,9 +595,10 @@
        mutex_spin_enter(&tty_lock);
        for (;;) {
                if (ISSET(tp->t_state, TS_ISOPEN)) {
-                       if (pti->pt_flags & PF_PKT && pti->pt_send) {
+                       if (pti->pt_flags & PF_PKT && (c = pti->pt_send)) {
+                               pti->pt_send = 0;
                                mutex_spin_exit(&tty_lock);
-                               error = ureadc((int)pti->pt_send, uio);
+                               error = ureadc(c, uio);
                                if (error)
                                        return (error);
                                /*
@@ -611,15 +613,14 @@
                                        uiomove((void *) &tp->t_termios,
                                                cc, uio);
                                }
-                               pti->pt_send = 0;
                                return (0);
                        }
-                       if (pti->pt_flags & PF_UCNTL && pti->pt_ucntl) {
+                       if (pti->pt_flags & PF_UCNTL && (c = pti->pt_ucntl)) {
+                               pti->pt_ucntl = 0;
                                mutex_spin_exit(&tty_lock);
-                               error = ureadc((int)pti->pt_ucntl, uio);
+                               error = ureadc(c, uio);
                                if (error)
                                        return (error);
-                               pti->pt_ucntl = 0;
                                return (0);
                        }
                        if (tp->t_outq.c_cc && !ISSET(tp->t_state, TS_TTSTOP))