13902 Fix for 13717 may break 8-disk raidz2
13915 installctx() blocking allocate causes problems
Portions contributed by: Jerry Jelinek <gjelinek@gmail.com>
Change-Id: I934d69946cec42630fc541fa8c7385b862b69ca2

@@ -19,11 +19,11 @@
  * CDDL HEADER END
  */
 
 /*
  * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright 2018 Joyent, Inc.
+ * Copyright 2021 Joyent, Inc.
  * Copyright 2020 Oxide Computer Company
  */
 
 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
 /*        All Rights Reserved   */

@@ -716,12 +716,13 @@
 extern  void    thread_exit(void) __NORETURN;
 extern  void    thread_free(kthread_t *);
 extern  void    thread_rele(kthread_t *);
 extern  void    thread_join(kt_did_t);
 extern  int     reaper(void);
+extern  struct ctxop *installctx_preallocate(void);
 extern  void    installctx(kthread_t *, void *, void (*)(), void (*)(),
-    void (*)(), void (*)(), void (*)(), void (*)());
+    void (*)(), void (*)(), void (*)(), void (*)(), struct ctxop *);
 extern  int     removectx(kthread_t *, void *, void (*)(), void (*)(),
     void (*)(), void (*)(), void (*)(), void (*)());
 extern  void    savectx(kthread_t *);
 extern  void    restorectx(kthread_t *);
 extern  void    forkctx(kthread_t *, kthread_t *);