1845 allow disable of UNMAP via stmfadm(1M).

*** 1351,1360 ****
--- 1351,1363 ----
                  sli->sli_flags |= SLI_WRITE_PROTECTED;
          }
          if (sl->sl_flags & SL_SAVED_WRITE_CACHE_DISABLE) {
                  sli->sli_flags |= SLI_WRITEBACK_CACHE_DISABLE;
          }
+         if (sl->sl_flags & SL_SAVED_UNMAP_ENABLED) {
+                 sli->sli_flags |= SLI_UNMAP_ENABLED;
+         }
          if (sl->sl_flags & SL_VID_VALID) {
                  bcopy(sl->sl_vendor_id, sli->sli_vid, 8);
                  sli->sli_flags |= SLI_VID_VALID;
          }
          if (sl->sl_flags & SL_PID_VALID) {
*** 1387,1416 ****
          kmem_free(sli, sizeof (*sli) + s);
          return (ret);
  }
  
  /*
!  * Will scribble SL_UNMAP_ENABLED into sl_flags if we succeed.
   */
! static void
! do_unmap_setup(sbd_lu_t *sl)
  {
          ASSERT((sl->sl_flags & SL_UNMAP_ENABLED) == 0);
  
!         if ((sl->sl_flags & SL_ZFS_META) == 0)
!                 return; /* No UNMAP for you. */
  
!         sl->sl_flags |= SL_UNMAP_ENABLED;
  }
  
  int
  sbd_populate_and_register_lu(sbd_lu_t *sl, uint32_t *err_ret)
  {
          stmf_lu_t *lu = sl->sl_lu;
          stmf_status_t ret;
  
!         do_unmap_setup(sl);
  
          lu->lu_id = (scsi_devid_desc_t *)sl->sl_device_id;
          if (sl->sl_alias) {
                  lu->lu_alias = sl->sl_alias;
          } else {
--- 1390,1429 ----
          kmem_free(sli, sizeof (*sli) + s);
          return (ret);
  }
  
  /*
!  * Will scribble SL_UNMAP_ENABLED on or off in sl_flags if we succeed.
!  * Returns B_TRUE if the LU is UNMAP-capable.
   */
! static boolean_t
! do_unmap_setup(sbd_lu_t *sl, boolean_t enable)
  {
+         if ((sl->sl_flags & SL_ZFS_META) == 0) {
+                 sl->sl_flags &= ~SL_SAVED_UNMAP_ENABLED;
                  ASSERT((sl->sl_flags & SL_UNMAP_ENABLED) == 0);
+                 return (B_FALSE);       /* No UNMAP for you. */
+         }
  
!         if (enable)
!                 sl->sl_flags |= (SL_UNMAP_ENABLED | SL_SAVED_UNMAP_ENABLED);
!         else
!                 sl->sl_flags &= ~(SL_UNMAP_ENABLED | SL_SAVED_UNMAP_ENABLED);
  
!         return (B_TRUE);
  }
  
  int
  sbd_populate_and_register_lu(sbd_lu_t *sl, uint32_t *err_ret)
  {
          stmf_lu_t *lu = sl->sl_lu;
          stmf_status_t ret;
  
! #if 0
!         /* Always try and enable UNMAP upon bringup. */
!         (void) do_unmap_setup(sl, B_TRUE);
! #endif
  
          lu->lu_id = (scsi_devid_desc_t *)sl->sl_device_id;
          if (sl->sl_alias) {
                  lu->lu_alias = sl->sl_alias;
          } else {
*** 1833,1842 ****
--- 1846,1860 ----
                  sl->sl_flags |= SL_REV_VALID;
          }
          if (slu->slu_write_protected) {
                  sl->sl_flags |= SL_WRITE_PROTECTED;
          }
+ 
+         if (slu->slu_unmap) {
+                 (void) do_unmap_setup(sl, B_TRUE);
+         }
+ 
          if (slu->slu_writeback_cache_disable) {
                  sl->sl_flags |= SL_WRITEBACK_CACHE_DISABLE |
                      SL_SAVED_WRITE_CACHE_DISABLE;
          }
  
*** 2475,2484 ****
--- 2493,2505 ----
                      sli->sli_mgmt_url_offset);
          }
          if (sli->sli_flags & SLI_WRITE_PROTECTED) {
                  sl->sl_flags |= SL_WRITE_PROTECTED;
          }
+         if (sli->sli_flags & SLI_UNMAP_ENABLED) {
+                 sl->sl_flags |= SL_UNMAP_ENABLED;
+         }
          if (sli->sli_flags & SLI_VID_VALID) {
                  sl->sl_flags |= SL_VID_VALID;
                  bcopy(sli->sli_vid, sl->sl_vendor_id, 8);
          }
          if (sli->sli_flags & SLI_PID_VALID) {
*** 2695,2704 ****
--- 2716,2736 ----
                  *err_ret = SBD_RET_ACCESS_STATE_FAILED;
                  ret = EINVAL;
                  goto smm_err_out;
          }
  
+         /* Change UNMAP status... */
+         if (mlu->mlu_unmap_valid) {
+                 mutex_enter(&sl->sl_lock);
+                 ASSERT(ret == 0);
+                 if (!do_unmap_setup(sl, mlu->mlu_unmap))
+                         ret = EINVAL;
+                 mutex_exit(&sl->sl_lock);
+                 if (ret != 0)
+                         goto smm_err_out;
+         }
+ 
          /* check for write cache change */
          if (mlu->mlu_writeback_cache_disable_valid) {
                  /* set wce on device */
                  sret = sbd_wcd_set(mlu->mlu_writeback_cache_disable, sl);
                  if (!mlu->mlu_writeback_cache_disable && sret != SBD_SUCCESS) {
*** 3329,3338 ****
--- 3361,3374 ----
          } else {
                  bcopy(sbd_revision, oslp->slp_rev, 4);
          }
          bcopy(sl->sl_device_id + 4, oslp->slp_guid, 16);
  
+         if (sl->sl_flags & SL_UNMAP_ENABLED)
+                 oslp->slp_unmap_cur = 1;
+         if (sl->sl_flags & SL_SAVED_UNMAP_ENABLED)
+                 oslp->slp_unmap_saved = 1;
          if (sl->sl_flags & SL_WRITEBACK_CACHE_DISABLE)
                  oslp->slp_writeback_cache_disable_cur = 1;
          if (sl->sl_flags & SL_SAVED_WRITE_CACHE_DISABLE)
                  oslp->slp_writeback_cache_disable_saved = 1;
          if (sl->sl_flags & SL_WRITE_PROTECTED)