target: Convert se_node_acl->acl_group removal to use ->acl_kref

This patch converts core_tpg_del_initiator_node_acl() shutdown from configfs
context to use se_node_acl->acl_kref and ->acl_free_comp in order to wait for
outstanding fabric callbacks to complete via transport_deregister_session()
callbacks before waking ->acl_free_comp from the last ->acl_kref put.

It also changes core_tpg_del_initiator_node_acl() to setup a local sess_list
with target_get_session() + acl->acl_stop = 1 for active sessions that will
be shutdown, and changes transport_deregister_session_configfs() to check
for ->acl_stop usage.

Cc: Roland Dreier <roland@purestorage.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Joern Engel <joern@logfs.org>
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index bbed260..f3ea385 100644 (file)
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -452,9 +452,10 @@ int core_tpg_del_initiator_node_acl(
        struct se_node_acl *acl,
        int force)
 {
+       LIST_HEAD(sess_list);
        struct se_session *sess, *sess_tmp;
        unsigned long flags;
-       int dynamic_acl = 0;
+       int dynamic_acl = 0, rc;
 
        spin_lock_irq(&tpg->acl_node_lock);
        if (acl->dynamic_node_acl) {
@@ -465,27 +466,34 @@ int core_tpg_del_initiator_node_acl(
        tpg->num_node_acls--;
        spin_unlock_irq(&tpg->acl_node_lock);
 
-       spin_lock_irqsave(&tpg->session_lock, flags);
-       list_for_each_entry_safe(sess, sess_tmp,
-                               &tpg->tpg_sess_list, sess_list) {
-               if (sess->se_node_acl != acl)
-                       continue;
-               /*
-                * Determine if the session needs to be closed by our context.
-                */
-               if (!tpg->se_tpg_tfo->shutdown_session(sess))
+       spin_lock_irqsave(&acl->nacl_sess_lock, flags);
+       acl->acl_stop = 1;
+
+       list_for_each_entry_safe(sess, sess_tmp, &acl->acl_sess_list,
+                               sess_acl_list) {
+               if (sess->sess_tearing_down != 0)
                        continue;
 
-               spin_unlock_irqrestore(&tpg->session_lock, flags);
-               /*
-                * If the $FABRIC_MOD session for the Initiator Node ACL exists,
-                * forcefully shutdown the $FABRIC_MOD session/nexus.
-                */
-               tpg->se_tpg_tfo->close_session(sess);
+               target_get_session(sess);
+               list_move(&sess->sess_acl_list, &sess_list);
+       }
+       spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
+
+       list_for_each_entry_safe(sess, sess_tmp, &sess_list, sess_acl_list) {
+               list_del(&sess->sess_acl_list);
 
-               spin_lock_irqsave(&tpg->session_lock, flags);
+               rc = tpg->se_tpg_tfo->shutdown_session(sess);
+               target_put_session(sess);
+               if (!rc)
+                       continue;
+               target_put_session(sess);
        }
-       spin_unlock_irqrestore(&tpg->session_lock, flags);
+       target_put_nacl(acl);
+       /*
+        * Wait for last target_put_nacl() to complete in target_complete_nacl()
+        * for active fabric session transport_deregister_session() callbacks.
+        */
+       wait_for_completion(&acl->acl_free_comp);
 
        core_tpg_wait_for_nacl_pr_ref(acl);
        core_clear_initiator_node_from_tpg(acl, tpg);

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index efefbec..ba8eb83 100644 (file)
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -360,7 +360,8 @@ void transport_deregister_session_configfs(struct se_session *se_sess)
        se_nacl = se_sess->se_node_acl;
        if (se_nacl) {
                spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
-               list_del(&se_sess->sess_acl_list);
+               if (se_nacl->acl_stop == 0)
+                       list_del(&se_sess->sess_acl_list);
                /*
                 * If the session list is empty, then clear the pointer.
                 * Otherwise, set the struct se_session pointer from the tail

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 2cda563..469678d 100644 (file)
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -620,6 +620,7 @@ struct se_node_acl {
        char                    initiatorname[TRANSPORT_IQN_LEN];
        /* Used to signal demo mode created ACL, disabled by default */
        bool                    dynamic_node_acl;
+       bool                    acl_stop:1;
        u32                     queue_depth;
        u32                     acl_index;
        u64                     num_cmds;