target/tcm_fc: Limit to 1 TPG per wwn

tcm_fc doesn't support multiple TPGs per wwn. For proof, see
ft_lport_find_tpg. Enforce this in the code.

Replace ft_lport_wwn.tpg_list with a single pointer. We can't fold ft_tpg
into ft_lport_wwn because they can have different lifetimes.

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

2 files changed, 12 insertions, 11 deletions

diff --git a/drivers/target/tcm_fc/tcm_fc.h b/drivers/target/tcm_fc/tcm_fc.h
index aba6861c362b..7290f8fb53f0 100644
--- a/drivers/target/tcm_fc/tcm_fc.h
+++ b/drivers/target/tcm_fc/tcm_fc.h
@@ -96,7 +96,6 @@ struct ft_tpg {
         u32 index;
         struct ft_lport_acl *lport_acl;
         struct ft_tport *tport;         /* active tport or NULL */
-        struct list_head list;          /* linkage in ft_lport_acl tpg_list */
         struct list_head lun_list;      /* head of LUNs */
         struct se_portal_group se_tpg;
         struct workqueue_struct *workqueue;
@@ -105,8 +104,8 @@ struct ft_tpg {
 struct ft_lport_acl {
         u64 wwpn;
         char name[FT_NAMELEN];
+        struct ft_tpg *tpg;
         struct list_head list;
-        struct list_head tpg_list;
         struct se_wwn fc_lport_wwn;
 };
 
diff --git a/drivers/target/tcm_fc/tfc_conf.c b/drivers/target/tcm_fc/tfc_conf.c
index 9c2da1ff886a..ccfa328e0367 100644
--- a/drivers/target/tcm_fc/tfc_conf.c
+++ b/drivers/target/tcm_fc/tfc_conf.c
@@ -318,6 +318,11 @@ static struct se_portal_group *ft_add_tpg(
         if (index > UINT_MAX)
                 return NULL;
 
+        if ((index != 1)) {
+                pr_err("Error, a single TPG=1 is used for HW port mappings\n");
+                return ERR_PTR(-ENOSYS);
+        }
+
         lacl = container_of(wwn, struct ft_lport_acl, fc_lport_wwn);
         tpg = kzalloc(sizeof(*tpg), GFP_KERNEL);
         if (!tpg)
@@ -342,7 +347,7 @@ static struct se_portal_group *ft_add_tpg(
         tpg->workqueue = wq;
 
         mutex_lock(&ft_lport_lock);
-        list_add_tail(&tpg->list, &lacl->tpg_list);
+        lacl->tpg = tpg;
         mutex_unlock(&ft_lport_lock);
 
         return &tpg->se_tpg;
@@ -351,6 +356,7 @@ static struct se_portal_group *ft_add_tpg(
 static void ft_del_tpg(struct se_portal_group *se_tpg)
 {
         struct ft_tpg *tpg = container_of(se_tpg, struct ft_tpg, se_tpg);
+        struct ft_lport_acl *lacl = tpg->lport_acl;
 
         pr_debug("del tpg %s\n",
                     config_item_name(&tpg->se_tpg.tpg_group.cg_item));
@@ -361,7 +367,8 @@ static void ft_del_tpg(struct se_portal_group *se_tpg)
         synchronize_rcu();
 
         mutex_lock(&ft_lport_lock);
-        list_del(&tpg->list);
+        lacl->tpg = NULL;
+
         if (tpg->tport) {
                 tpg->tport->tpg = NULL;
                 tpg->tport = NULL;
@@ -381,14 +388,10 @@ static void ft_del_tpg(struct se_portal_group *se_tpg)
 struct ft_tpg *ft_lport_find_tpg(struct fc_lport *lport)
 {
         struct ft_lport_acl *lacl;
-        struct ft_tpg *tpg;
 
         list_for_each_entry(lacl, &ft_lport_list, list) {
-                if (lacl->wwpn == lport->wwpn) {
-                        list_for_each_entry(tpg, &lacl->tpg_list, list)
-                                return tpg; /* XXX for now return first entry */
-                        return NULL;
-                }
+                if (lacl->wwpn == lport->wwpn)
+                        return lacl->tpg;
         }
         return NULL;
 }
@@ -417,7 +420,6 @@ static struct se_wwn *ft_add_lport(
         if (!lacl)
                 return NULL;
         lacl->wwpn = wwpn;
-        INIT_LIST_HEAD(&lacl->tpg_list);
 
         mutex_lock(&ft_lport_lock);
         list_for_each_entry(old_lacl, &ft_lport_list, list) {