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 signalfd facility, a Linux-borne facility for
   * file descriptor-based synchronous signal consumption.
--- 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 signalfd facility, a Linux-borne facility for
   * file descriptor-based synchronous signal consumption.
*** 558,568 ****
              set.__sigbits[1]) |
              (((p->p_sig.__sigbits[2] | t->t_sig.__sigbits[2]) &
              set.__sigbits[2]) & FILLSET2));
  }
  
- _NOTE(ARGSUSED(4))
  static int
  signalfd_poll(dev_t dev, short events, int anyyet, short *reventsp,
      struct pollhead **phpp)
  {
          signalfd_state_t *state, **sstate;
--- 558,567 ----
*** 579,589 ****
          if (signalfd_sig_pending(p, t, state->sfd_set) != 0)
                  revents |= POLLRDNORM | POLLIN;
  
          mutex_exit(&state->sfd_lock);
  
!         if (!(*reventsp = revents & events) && !anyyet) {
                  sigfd_proc_state_t *pstate;
                  sigfd_poll_waiter_t *pw;
  
                  /*
                   * Enable pollwakeup handling.
--- 578,589 ----
          if (signalfd_sig_pending(p, t, state->sfd_set) != 0)
                  revents |= POLLRDNORM | POLLIN;
  
          mutex_exit(&state->sfd_lock);
  
!         *reventsp = revents & events;
!         if ((*reventsp == 0 && !anyyet) || (events & POLLET)) {
                  sigfd_proc_state_t *pstate;
                  sigfd_poll_waiter_t *pw;
  
                  /*
                   * Enable pollwakeup handling.