target: Subsume se_port + t10_alua_tg_pt_gp_member into se_lun

This patch eliminates all se_port + t10_alua_tg_pt_gp_member usage,
and converts current users to direct se_lun pointer dereference.

This includes the removal of core_export_port(), core_release_port()
core_dev_export() and core_dev_unexport().  Along with conversion
of special case se_lun pointer dereference within PR ALL_TG_PT=1
and ALUA access state transition UNIT_ATTENTION handling.

Also, update core_enable_device_list_for_node() to reference the
new per se_lun->lun_deve_list when creating a new entry, or
replacing an existing one via RCU.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 4313eea..f97b969 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -2889,21 +2889,16 @@
 	struct t10_alua_tg_pt_gp *tg_pt_gp,
 	char *page)
 {
-	struct se_port *port;
-	struct se_portal_group *tpg;
 	struct se_lun *lun;
-	struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;
 	ssize_t len = 0, cur_len;
 	unsigned char buf[TG_PT_GROUP_NAME_BUF];
 
 	memset(buf, 0, TG_PT_GROUP_NAME_BUF);
 
 	spin_lock(&tg_pt_gp->tg_pt_gp_lock);
-	list_for_each_entry(tg_pt_gp_mem, &tg_pt_gp->tg_pt_gp_mem_list,
-			tg_pt_gp_mem_list) {
-		port = tg_pt_gp_mem->tg_pt;
-		tpg = port->sep_tpg;
-		lun = port->sep_lun;
+	list_for_each_entry(lun, &tg_pt_gp->tg_pt_gp_lun_list,
+			lun_tg_pt_gp_link) {
+		struct se_portal_group *tpg = lun->lun_tpg;
 
 		cur_len = snprintf(buf, TG_PT_GROUP_NAME_BUF, "%s/%s/tpgt_%hu"
 			"/%s\n", tpg->se_tpg_tfo->get_fabric_name(),