3354 kernel crash in rpcsec_gss after using gsscred
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed by: Carlos Neira <cneirabustos@gmail.com>
Approved by: Robert Mustacchi <rm@joyent.com>
re #12783 rb4338 Flow control is needed in rpcmod when the NFS server is unable to keep up with the network

*** 18,28 ****
--- 18,30 ----
   *
   * CDDL HEADER END
   */
  /*
   * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
+  * Copyright 2012 Marcel Telka <marcel@telka.sk>
   * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
+  * Copyright 2018 OmniOS Community Edition (OmniOSce) Association.
   */
  /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
  /* All Rights Reserved */
  /*
   * Portions of this source code were derived from Berkeley
*** 187,197 ****
                  /* destroy a clone xprt */
          void    (*xp_start)(SVCMASTERXPRT *);
                  /* `ready-to-receive' */
          void    (*xp_clone_xprt)(SVCXPRT *, SVCXPRT *);
                  /* transport specific clone function */
!         void    (*xp_tattrs) (SVCXPRT *, int, void **);
  };
  
  #define SVC_TATTR_ADDRMASK      1
  
  #else   /* _KERNEL */
--- 189,203 ----
                  /* destroy a clone xprt */
          void    (*xp_start)(SVCMASTERXPRT *);
                  /* `ready-to-receive' */
          void    (*xp_clone_xprt)(SVCXPRT *, SVCXPRT *);
                  /* transport specific clone function */
!         void    (*xp_tattrs)(SVCXPRT *, int, void **);
!                 /* transport specific hold function */
!         void    (*xp_hold)(queue_t *);
!                 /* transport specific release function */
!         void    (*xp_release)(queue_t *, mblk_t *, bool_t);
  };
  
  #define SVC_TATTR_ADDRMASK      1
  
  #else   /* _KERNEL */
*** 530,539 ****
--- 536,553 ----
  #define SVC_CLONE_XPRT(src_xprt, dst_xprt) \
          if ((src_xprt)->xp_ops->xp_clone_xprt) \
                  (*(src_xprt)->xp_ops->xp_clone_xprt) \
                      (src_xprt, dst_xprt)
  
+ #define SVC_HOLD(xprt) \
+         if ((xprt)->xp_ops->xp_hold) \
+                 (*(xprt)->xp_ops->xp_hold)((xprt)->xp_wq)
+ 
+ #define SVC_RELE(xprt, mp, enable) \
+         if ((xprt)->xp_ops->xp_release) \
+                 (*(xprt)->xp_ops->xp_release)((xprt)->xp_wq, (mp), (enable))
+ 
  #define SVC_RECV(clone_xprt, mp, msg) \
          (*(clone_xprt)->xp_ops->xp_recv)((clone_xprt), (mp), (msg))
  
  /*
   * PSARC 2003/523 Contract Private Interface
*** 726,735 ****
--- 740,758 ----
  extern void     xprt_register();
  extern void     xprt_unregister();
  #endif /* __STDC__ */
  #endif  /* _KERNEL */
  
+ #ifdef _KERNEL
+ /*
+  * Transport hold and release.
+  */
+ extern void rpcmod_hold(queue_t *);
+ extern void rpcmod_release(queue_t *, mblk_t *, bool_t);
+ extern void mir_svc_hold(queue_t *);
+ extern void mir_svc_release(queue_t *, mblk_t *, bool_t);
+ #endif /* _KERNEL */
  
  /*
   * When the service routine is called, it must first check to see if it
   * knows about the procedure;  if not, it should call svcerr_noproc
   * and return.  If so, it should deserialize its arguments via