diff --git a/usr/src/lib/fm/topo/modules/common/disk/disk_common.c b/usr/src/lib/fm/topo/modules/common/disk/disk_common.c
index 260a4689baed..da7a70266297 100644
--- a/usr/src/lib/fm/topo/modules/common/disk/disk_common.c
+++ b/usr/src/lib/fm/topo/modules/common/disk/disk_common.c
@@ -143,7 +143,7 @@ disk_set_props(topo_mod_t *mod, tnode_t *parent,
 	nvlist_t	*asru = NULL, *drive_attrs;
 	char		*label = NULL;
 	nvlist_t	*fmri = NULL;
-	dm_descriptor_t drive_descr = NULL;
+	dm_descriptor_t drive_descr = 0;
 	uint32_t	rpm;
 	int		err;
 
@@ -287,7 +287,7 @@ disk_set_props(topo_mod_t *mod, tnode_t *parent,
 
 	if (dnode->ddn_devid == NULL ||
 	    (drive_descr = dm_get_descriptor_by_name(DM_DRIVE,
-	    dnode->ddn_devid, &err)) == NULL ||
+	    dnode->ddn_devid, &err)) == 0 ||
 	    (drive_attrs = dm_get_attributes(drive_descr, &err)) == NULL)
 		goto out;
 
@@ -305,7 +305,7 @@ disk_set_props(topo_mod_t *mod, tnode_t *parent,
 	err = 0;
 
 out:
-	if (drive_descr != NULL)
+	if (drive_descr != 0)
 		dm_free_descriptor(drive_descr);
 	nvlist_free(fmri);
 	if (label)
@@ -353,7 +353,7 @@ disk_temp_reading(topo_mod_t *mod, tnode_t *node, topo_version_t vers,
 {
 	char *devid;
 	uint32_t temp;
-	dm_descriptor_t drive_descr = NULL;
+	dm_descriptor_t drive_descr = 0;
 	nvlist_t *drive_stats, *pargs, *nvl;
 	int err;
 
@@ -368,7 +368,7 @@ disk_temp_reading(topo_mod_t *mod, tnode_t *node, topo_version_t vers,
 	}
 
 	if ((drive_descr = dm_get_descriptor_by_name(DM_DRIVE, devid,
-	    &err)) == NULL) {
+	    &err)) == 0) {
 		topo_mod_dprintf(mod, "failed to get drive decriptor for %s",
 		    devid);
 		return (topo_mod_seterrno(mod, EMOD_UNKNOWN));
diff --git a/usr/src/lib/fm/topo/modules/common/ses/ses.c b/usr/src/lib/fm/topo/modules/common/ses/ses.c
index 2ac0dfdd346c..03b12d68cfc0 100644
--- a/usr/src/lib/fm/topo/modules/common/ses/ses.c
+++ b/usr/src/lib/fm/topo/modules/common/ses/ses.c
@@ -580,7 +580,7 @@ ses_contract_thread(void *arg)
 				(void) snprintf(buf, sizeof (buf),
 				    "abandon old contract %d", stp->set_ctid);
 				ses_ct_print(buf);
-				stp->set_ctid = NULL;
+				stp->set_ctid = 0;
 			}
 			(void) ct_ctl_abandon(ctlfd);
 		}
@@ -702,7 +702,7 @@ ses_create_contract(topo_mod_t *mod, ses_enum_target_t *stp)
 	int tfd, len, rval;
 	char link_path[PATH_MAX];
 
-	stp->set_ctid = NULL;
+	stp->set_ctid = 0;
 
 	/* convert "/dev" path into "/devices" path */
 	if ((len = readlink(stp->set_devpath, link_path, PATH_MAX)) < 0) {
@@ -749,7 +749,7 @@ ses_target_free(topo_mod_t *mod, ses_enum_target_t *stp)
 			ctlfd = open64(path, O_WRONLY);
 			(void) ct_ctl_abandon(ctlfd);
 			(void) close(ctlfd);
-			stp->set_ctid = NULL;
+			stp->set_ctid = 0;
 		}
 		(void) pthread_mutex_unlock(&stp->set_lock);
 		ses_ssl_free(mod, stp);
@@ -939,7 +939,7 @@ ses_node_lock(topo_mod_t *mod, tnode_t *tn)
 		 * contract (ie we've had the offline event but not yet the
 		 * negend). If so, just return failure.
 		 */
-		if (tp->set_ctid != NULL) {
+		if (tp->set_ctid != 0) {
 			(void) topo_mod_seterrno(mod, EMOD_METHOD_NOTSUP);
 			(void) pthread_mutex_unlock(&tp->set_lock);
 			return (NULL);
@@ -1899,13 +1899,13 @@ ses_create_esc_sasspecific(ses_enum_data_t *sdp, ses_enum_node_t *snp,
 	topo_mod_t *mod = sdp->sed_mod;
 	tnode_t	*exptn, *contn;
 	boolean_t found;
-	sas_connector_phy_data_t connectors[64] = {NULL};
+	sas_connector_phy_data_t connectors[64] = {0};
 	uint64_t max;
 	ses_enum_node_t *ctlsnp, *xsnp, *consnp;
 	ses_node_t *np = snp->sen_node;
 	nvlist_t *props, *psprops;
 	uint64_t index, psindex, conindex, psstatus, i, j, count;
-	int64_t cidxlist[256] = {NULL};
+	int64_t cidxlist[256] = {0};
 	int phycount;
 
 	props = ses_node_props(np);
diff --git a/usr/src/lib/fm/topo/modules/common/smbios/smbios_enum.c b/usr/src/lib/fm/topo/modules/common/smbios/smbios_enum.c
index cdbb9d566efd..a66396e17071 100644
--- a/usr/src/lib/fm/topo/modules/common/smbios/smbios_enum.c
+++ b/usr/src/lib/fm/topo/modules/common/smbios/smbios_enum.c
@@ -153,7 +153,7 @@ smbios_make_slot(smb_enum_data_t *smed, smbios_memdevice_t *smb_md)
 		return (NULL);
 	}
 	if (topo_node_fru(smed->sme_pnode, &fmri, NULL, &err) != 0 ||
-	    topo_node_fru_set(slotnode, fmri, NULL, &err) != 0) {
+	    topo_node_fru_set(slotnode, fmri, 0, &err) != 0) {
 		topo_mod_dprintf(mod, "failed to set FRU on %s=%d: %s", SLOT,
 		    smed->sme_slot_inst, topo_strerror(err));
 		nvlist_free(fmri);
@@ -262,7 +262,7 @@ smbios_make_dimm(smb_enum_data_t *smed, smbios_memdevice_t *smb_md)
 	topo_pgroup_hcset(dimmnode, auth);
 	nvlist_free(auth);
 
-	if (topo_node_fru_set(dimmnode, fmri, NULL, &err) != 0) {
+	if (topo_node_fru_set(dimmnode, fmri, 0, &err) != 0) {
 		topo_mod_dprintf(mod, "failed to set FRU on %s: %s",
 		    DIMM, topo_strerror(err));
 		nvlist_free(fmri);
@@ -487,7 +487,7 @@ smbios_enum_motherboard(smbios_hdl_t *shp, smb_enum_data_t *smed)
 	topo_pgroup_hcset(mbnode, auth);
 	nvlist_free(auth);
 
-	if (topo_node_fru_set(mbnode, fmri, NULL, &err) != 0) {
+	if (topo_node_fru_set(mbnode, fmri, 0, &err) != 0) {
 		topo_mod_dprintf(mod, "failed to set FRU on %s: %s",
 		    MOTHERBOARD, topo_strerror(err));
 		nvlist_free(fmri);
diff --git a/usr/src/lib/fm/topo/modules/i86pc/chip/chip_intel.c b/usr/src/lib/fm/topo/modules/i86pc/chip/chip_intel.c
index fa438351612b..a57866c403c7 100644
--- a/usr/src/lib/fm/topo/modules/i86pc/chip/chip_intel.c
+++ b/usr/src/lib/fm/topo/modules/i86pc/chip/chip_intel.c
@@ -429,7 +429,7 @@ mc_nb_create(topo_mod_t *mod, uint16_t chip_smbid, tnode_t *pnode,
 		}
 	}
 
-	return (NULL);
+	return (0);
 }
 
 int
@@ -451,7 +451,7 @@ mc_node_create(topo_mod_t *mod, uint16_t chip_smbid, tnode_t *pnode,
 
 		free(buf);
 		(void) close(mc_fd);
-		return (NULL);
+		return (0);
 	}
 	(void) close(mc_fd);
 	(void) nvlist_unpack(buf, mcs.mcs_size, &nvl, 0);
@@ -460,11 +460,11 @@ mc_node_create(topo_mod_t *mod, uint16_t chip_smbid, tnode_t *pnode,
 	if (nvlist_lookup_uint8(nvl, MCINTEL_NVLIST_VERSTR, &ver) != 0) {
 		whinge(mod, NULL, "mc nvlist is not versioned\n");
 		nvlist_free(nvl);
-		return (NULL);
+		return (0);
 	} else if (ver != MCINTEL_NVLIST_VERS0) {
 		whinge(mod, NULL, "mc nvlist version mismatch\n");
 		nvlist_free(nvl);
-		return (NULL);
+		return (0);
 	}
 
 	rc = mc_nb_create(mod, chip_smbid, pnode, name, auth, nvl);
diff --git a/usr/src/lib/fm/topo/modules/i86pc/x86pi/x86pi_hostbridge.c b/usr/src/lib/fm/topo/modules/i86pc/x86pi/x86pi_hostbridge.c
index 898037fe1c4d..8b3692d99a88 100644
--- a/usr/src/lib/fm/topo/modules/i86pc/x86pi/x86pi_hostbridge.c
+++ b/usr/src/lib/fm/topo/modules/i86pc/x86pi/x86pi_hostbridge.c
@@ -106,7 +106,7 @@ pciex_process(topo_mod_t *mod, tnode_t *tn_hbr, di_node_t rcn,
 
 	if ((did = did_create(mod, rcn, topo_node_instance(tn_bb),
 	    topo_node_instance(tn_hbr), rci, TRUST_BDF)) == NULL)
-		return (NULL);
+		return (-1);
 
 	did_markrc(did);
 
@@ -241,7 +241,7 @@ x86pi_gen_hbr(topo_mod_t *mod, tnode_t *tn_bb,
 	smbios_pciexrc_t smb_rc;
 	int		i, rv, err = 0;
 	const char	*f = "x86pi_gen_hbr";
-	smbios_hdl_t 	*shp;
+	smbios_hdl_t	*shp;
 
 	shp = topo_mod_smbios(mod);
 	if (shp == NULL)