11969 Attempting to attach an invalid nvme namespace will cause a panic
Reviewed by: Robert Mustacchi <rm+illumos@fingolfin.org>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>

*** 4548,4557 ****
--- 4548,4560 ----
                  return (EPERM);
  
          if (nsid == 0)
                  return (EINVAL);
  
+         if (nvme->n_ns[nsid - 1].ns_ignore)
+                 return (0);
+ 
          rv = bd_detach_handle(nvme->n_ns[nsid - 1].ns_bd_hdl);
          if (rv != DDI_SUCCESS)
                  rv = EBUSY;
  
          return (rv);
*** 4578,4587 ****
--- 4581,4598 ----
          if (nvme_init_ns(nvme, nsid) != DDI_SUCCESS)
                  return (EIO);
  
          kmem_free(idns, sizeof (nvme_identify_nsid_t));
  
+         if (nvme->n_ns[nsid - 1].ns_ignore)
+                 return (ENOTSUP);
+ 
+         if (nvme->n_ns[nsid - 1].ns_bd_hdl == NULL)
+                 nvme->n_ns[nsid - 1].ns_bd_hdl = bd_alloc_handle(
+                     &nvme->n_ns[nsid - 1], &nvme_bd_ops, &nvme->n_prp_dma_attr,
+                     KM_SLEEP);
+ 
          rv = bd_attach_handle(nvme->n_dip, nvme->n_ns[nsid - 1].ns_bd_hdl);
          if (rv != DDI_SUCCESS)
                  rv = EBUSY;
  
          return (rv);