LOCAL: LDI -- make walks removal-safe

*** 142,151 ****
--- 142,154 ----
          { LDI_EV_DEGRADE, 0, CT_DEV_EV_DEGRADED},
          { LDI_EV_DEVICE_REMOVE, 0, 0},
          { NULL}                 /* must terminate list */
  };
  
+ static ldi_ev_callback_impl_t *walker_next = NULL;
+ static ldi_ev_callback_impl_t *walker_prev = NULL;
+ 
  void
  ldi_init(void)
  {
          int i;
  
*** 3327,3338 ****
          LDI_EVDBG((CE_NOTE, "ldi_invoke_notify(): entered: dip=%p, ev=%s",
              (void *)dip, event));
  
          ret = LDI_EV_NONE;
          ldi_ev_lock();
          listp = &ldi_ev_callback_list.le_head;
!         for (lecp = list_head(listp); lecp; lecp = list_next(listp, lecp)) {
  
                  /* Check if matching device */
                  if (!ldi_ev_device_match(lecp, dip, dev, spec_type))
                          continue;
  
--- 3330,3343 ----
          LDI_EVDBG((CE_NOTE, "ldi_invoke_notify(): entered: dip=%p, ev=%s",
              (void *)dip, event));
  
          ret = LDI_EV_NONE;
          ldi_ev_lock();
+         VERIFY(walker_next == NULL);
          listp = &ldi_ev_callback_list.le_head;
!         for (lecp = list_head(listp); lecp; lecp = walker_next) {
!                 walker_next = list_next(listp, lecp);
  
                  /* Check if matching device */
                  if (!ldi_ev_device_match(lecp, dip, dev, spec_type))
                          continue;
  
*** 3384,3394 ****
  
          /*
           * Undo notifies already sent
           */
          lecp = list_prev(listp, lecp);
!         for (; lecp; lecp = list_prev(listp, lecp)) {
  
                  /*
                   * Check if matching device
                   */
                  if (!ldi_ev_device_match(lecp, dip, dev, spec_type))
--- 3389,3401 ----
  
          /*
           * Undo notifies already sent
           */
          lecp = list_prev(listp, lecp);
!         VERIFY(walker_prev == NULL);
!         for (; lecp; lecp = walker_prev) {
!                 walker_prev = list_prev(listp, lecp);
  
                  /*
                   * Check if matching device
                   */
                  if (!ldi_ev_device_match(lecp, dip, dev, spec_type))
*** 3435,3444 ****
--- 3442,3453 ----
                          lecp->lec_finalize = NULL;
                  }
          }
  
  out:
+         walker_next = NULL;
+         walker_prev = NULL;
          ldi_ev_unlock();
  
          if (ret == LDI_EV_NONE) {
                  LDI_EVDBG((CE_NOTE, "ldi_invoke_notify(): no matching "
                      "LDI callbacks"));
*** 3550,3561 ****
  
          LDI_EVDBG((CE_NOTE, "ldi_invoke_finalize(): entered: dip=%p, result=%d"
              " event=%s", (void *)dip, ldi_result, event));
  
          ldi_ev_lock();
          listp = &ldi_ev_callback_list.le_head;
!         for (lecp = list_head(listp); lecp; lecp = list_next(listp, lecp)) {
  
                  if (lecp->lec_finalize == NULL) {
                          LDI_EVDBG((CE_NOTE, "ldi_invoke_finalize(): No "
                              "finalize. Skipping"));
                          continue;       /* Not interested in finalize */
--- 3559,3572 ----
  
          LDI_EVDBG((CE_NOTE, "ldi_invoke_finalize(): entered: dip=%p, result=%d"
              " event=%s", (void *)dip, ldi_result, event));
  
          ldi_ev_lock();
+         VERIFY(walker_next == NULL);
          listp = &ldi_ev_callback_list.le_head;
!         for (lecp = list_head(listp); lecp; lecp = walker_next) {
!                 walker_next = list_next(listp, lecp);
  
                  if (lecp->lec_finalize == NULL) {
                          LDI_EVDBG((CE_NOTE, "ldi_invoke_finalize(): No "
                              "finalize. Skipping"));
                          continue;       /* Not interested in finalize */
*** 3602,3611 ****
--- 3613,3623 ----
                              "ldi_invoke_finalize(): NULLing finalize after "
                              "calling 1 finalize following ldi_close"));
                          lecp->lec_finalize = NULL;
                  }
          }
+         walker_next = NULL;
          ldi_ev_unlock();
  
          if (found)
                  return;
  
*** 3683,3692 ****
--- 3695,3711 ----
          next = found = NULL;
          for (lecp = list_head(listp); lecp; lecp = next) {
                  next = list_next(listp, lecp);
                  if (lecp->lec_id == id) {
                          ASSERT(found == NULL);
+ 
+                         /* If there is a walk in progress, move it along... */
+                         if (walker_next == lecp)
+                                 walker_next = next;
+                         if (walker_prev == lecp)
+                                 walker_prev = list_prev(listp, walker_prev);
+ 
                          list_remove(listp, lecp);
                          found = lecp;
                  }
          }
          ldi_ev_unlock();