8634 epoll fails to wake on certain edge-triggered conditions
8635 epoll should not emit POLLNVAL
8636 recursive epoll should emit EPOLLRDNORM
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed by: Igor Kozhukhov <igor@dilos.org>

*** 8,18 ****
   * source.  A copy of the CDDL is also available via the Internet at
   * http://www.illumos.org/license/CDDL.
   */
  
  /*
!  * Copyright 2016 Joyent, Inc.
   */
  
  /*
   * Support for the eventfd facility, a Linux-borne facility for user-generated
   * file descriptor-based events.
--- 8,18 ----
   * source.  A copy of the CDDL is also available via the Internet at
   * http://www.illumos.org/license/CDDL.
   */
  
  /*
!  * Copyright 2017 Joyent, Inc.
   */
  
  /*
   * Support for the eventfd facility, a Linux-borne facility for user-generated
   * file descriptor-based events.
*** 226,237 ****
                  revents |= POLLRDNORM | POLLIN;
  
          if (state->efd_value < EVENTFD_VALMAX)
                  revents |= POLLWRNORM | POLLOUT;
  
!         if (!(*reventsp = revents & events) && !anyyet)
                  *phpp = &state->efd_pollhd;
  
          mutex_exit(&state->efd_lock);
  
          return (0);
  }
--- 226,239 ----
                  revents |= POLLRDNORM | POLLIN;
  
          if (state->efd_value < EVENTFD_VALMAX)
                  revents |= POLLWRNORM | POLLOUT;
  
!         *reventsp = revents & events;
!         if ((*reventsp == 0 && !anyyet) || (events & POLLET)) {
                  *phpp = &state->efd_pollhd;
+         }
  
          mutex_exit(&state->efd_lock);
  
          return (0);
  }