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9042 multiples of tty streams modules cause weirdness
Reviewed by: Randy Fishel <randyf@sibernet.com>
Reviewed by: Carlos Neira <cneirabustos@gmail.com>
Approved by: Hans Rosenfeld <rosenfeld@grumpf.hope-2000.org>
re #13613 rb4516 Tunables needs volatile keyword
@@ -19,16 +19,19 @@
* CDDL HEADER END
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
-
/*
* Copyright 2010 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
* Copyright (c) 2016 by Delphix. All rights reserved.
+ * Copyright 2018 OmniOS Community Edition (OmniOSce) Association.
*/
+/*
+ * Copyright 2013 Nexenta Systems, Inc. All rights reserved.
+ */
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/param.h>
#include <sys/errno.h>
@@ -218,11 +221,11 @@
* consumer - IP is no longer D_MTPERMOD, but there may be other
* modules/drivers depend on this syncq flow control, we prefer to
* choose a large number as the default value. For potential
* performance gain, this value is tunable in /etc/system.
*/
-int sq_max_size = 10000;
+volatile int sq_max_size = 10000;
/*
* The number of ciputctrl structures per syncq and stream we create when
* needed.
*/
@@ -2462,10 +2465,21 @@
if ((qflag & QMT_TYPEMASK) != QMTSAFE)
goto bad;
qflag |= _QDIRECT;
}
+ /*
+ * Private flag used to indicate that a streams module should only
+ * be pushed once. The TTY streams modules have this flag since if
+ * libc believes itself to be an xpg4 process then it will
+ * automatically and unconditionally push them when a PTS device is
+ * opened. If an application is not aware of this then without this
+ * flag we would end up with duplicate modules.
+ */
+ if (devflag & _D_SINGLE_INSTANCE)
+ qflag |= _QSINGLE_INSTANCE;
+
*qflagp = qflag;
*sqtypep = sqtype;
return (0);
bad: