scsi: target: sbp: Replace enable attr with ops.enable

Remove tpg/enable attribute. Add fabric ops enable_tpg implementation
instead.

Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Roman Bolshakov <[e-mail]>
Reviewed-by: Bart Van Assche <[e-mail]>
Reviewed-by: Mike Christie <[e-mail]>
Signed-off-by: Dmitry Bogdanov <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/target/sbp/sbp_target.c

···
 	return count;
 }
 
-static ssize_t sbp_tpg_enable_show(struct config_item *item, char *page)
+static int sbp_enable_tpg(struct se_portal_group *se_tpg, bool enable)
 {
-	struct se_portal_group *se_tpg = to_tpg(item);
 	struct sbp_tpg *tpg = container_of(se_tpg, struct sbp_tpg, se_tpg);
 	struct sbp_tport *tport = tpg->tport;
-	return sprintf(page, "%d\n", tport->enable);
-}
-
-static ssize_t sbp_tpg_enable_store(struct config_item *item,
-		const char *page, size_t count)
-{
-	struct se_portal_group *se_tpg = to_tpg(item);
-	struct sbp_tpg *tpg = container_of(se_tpg, struct sbp_tpg, se_tpg);
-	struct sbp_tport *tport = tpg->tport;
-	unsigned long val;
 	int ret;
 
-	if (kstrtoul(page, 0, &val) < 0)
-		return -EINVAL;
-	if ((val != 0) && (val != 1))
-		return -EINVAL;
-
-	if (tport->enable == val)
-		return count;
-
-	if (val) {
+	if (enable) {
 		if (sbp_count_se_tpg_luns(&tpg->se_tpg) == 0) {
 			pr_err("Cannot enable a target with no LUNs!\n");
 			return -EINVAL;
···
 		spin_unlock_bh(&se_tpg->session_lock);
 	}
 
-	tport->enable = val;
+	tport->enable = enable;
 
 	ret = sbp_update_unit_directory(tport);
 	if (ret < 0) {
···
 		return ret;
 	}
 
-	return count;
+	return 0;
 }
 
 CONFIGFS_ATTR(sbp_tpg_, directory_id);
-CONFIGFS_ATTR(sbp_tpg_, enable);
 
 static struct configfs_attribute *sbp_tpg_base_attrs[] = {
 	&sbp_tpg_attr_directory_id,
-	&sbp_tpg_attr_enable,
 	NULL,
 };
 
···
 	.fabric_make_wwn		= sbp_make_tport,
 	.fabric_drop_wwn		= sbp_drop_tport,
 	.fabric_make_tpg		= sbp_make_tpg,
+	.fabric_enable_tpg		= sbp_enable_tpg,
 	.fabric_drop_tpg		= sbp_drop_tpg,
 	.fabric_post_link		= sbp_post_link_lun,
 	.fabric_pre_unlink		= sbp_pre_unlink_lun,