scsi: target: Move cmd counter allocation

iSCSI needs to allocate its cmd counter per connection for MCS support
where we need to stop and wait on commands running on a connection instead
of per session. This moves the cmd counter allocation to
target_setup_session() which is used by drivers that need the stop+wait
behavior per session.

xcopy doesn't need stop+wait at all, so we will be OK moving the cmd
counter allocation outside of transport_init_session().

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Link: https://lore.kernel.org/r/20230319015620.96006-3-michael.christie@oracle.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 27 insertions, 28 deletions

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 3d6034f00dcd..60647a49a1d3 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -228,7 +228,7 @@ static void target_release_cmd_refcnt(struct percpu_ref *ref)
 	wake_up(&cmd_cnt->refcnt_wq);
 }
 
-static struct target_cmd_counter *target_alloc_cmd_counter(void)
+struct target_cmd_counter *target_alloc_cmd_counter(void)
 {
 	struct target_cmd_counter *cmd_cnt;
 	int rc;
@@ -252,6 +252,7 @@ free_cmd_cnt:
 	kfree(cmd_cnt);
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(target_alloc_cmd_counter);
 
 static void target_free_cmd_counter(struct target_cmd_counter *cmd_cnt)
 {
@@ -271,24 +272,14 @@ static void target_free_cmd_counter(struct target_cmd_counter *cmd_cnt)
  *
  * The caller must have zero-initialized @se_sess before calling this function.
  */
-int transport_init_session(struct se_session *se_sess)
+void transport_init_session(struct se_session *se_sess)
 {
 	INIT_LIST_HEAD(&se_sess->sess_list);
 	INIT_LIST_HEAD(&se_sess->sess_acl_list);
 	spin_lock_init(&se_sess->sess_cmd_lock);
-	se_sess->cmd_cnt = target_alloc_cmd_counter();
-	if (!se_sess->cmd_cnt)
-		return -ENOMEM;
-
-	return  0;
 }
 EXPORT_SYMBOL(transport_init_session);
 
-void transport_uninit_session(struct se_session *se_sess)
-{
-	target_free_cmd_counter(se_sess->cmd_cnt);
-}
-
 /**
  * transport_alloc_session - allocate a session object and initialize it
  * @sup_prot_ops: bitmask that defines which T10-PI modes are supported.
@@ -296,7 +287,6 @@ void transport_uninit_session(struct se_session *se_sess)
 struct se_session *transport_alloc_session(enum target_prot_op sup_prot_ops)
 {
 	struct se_session *se_sess;
-	int ret;
 
 	se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
 	if (!se_sess) {
@@ -304,11 +294,7 @@ struct se_session *transport_alloc_session(enum target_prot_op sup_prot_ops)
 				" se_sess_cache\n");
 		return ERR_PTR(-ENOMEM);
 	}
-	ret = transport_init_session(se_sess);
-	if (ret < 0) {
-		kmem_cache_free(se_sess_cache, se_sess);
-		return ERR_PTR(ret);
-	}
+	transport_init_session(se_sess);
 	se_sess->sup_prot_ops = sup_prot_ops;
 
 	return se_sess;
@@ -474,8 +460,13 @@ target_setup_session(struct se_portal_group *tpg,
 		     int (*callback)(struct se_portal_group *,
 				     struct se_session *, void *))
 {
+	struct target_cmd_counter *cmd_cnt;
 	struct se_session *sess;
+	int rc;
 
+	cmd_cnt = target_alloc_cmd_counter();
+	if (!cmd_cnt)
+		return ERR_PTR(-ENOMEM);
 	/*
 	 * If the fabric driver is using percpu-ida based pre allocation
 	 * of I/O descriptor tags, go ahead and perform that setup now..
@@ -485,29 +476,36 @@ target_setup_session(struct se_portal_group *tpg,
 	else
 		sess = transport_alloc_session(prot_op);
 
-	if (IS_ERR(sess))
-		return sess;
+	if (IS_ERR(sess)) {
+		rc = PTR_ERR(sess);
+		goto free_cnt;
+	}
+	sess->cmd_cnt = cmd_cnt;
 
 	sess->se_node_acl = core_tpg_check_initiator_node_acl(tpg,
 					(unsigned char *)initiatorname);
 	if (!sess->se_node_acl) {
-		transport_free_session(sess);
-		return ERR_PTR(-EACCES);
+		rc = -EACCES;
+		goto free_sess;
 	}
 	/*
 	 * Go ahead and perform any remaining fabric setup that is
 	 * required before transport_register_session().
 	 */
 	if (callback != NULL) {
-		int rc = callback(tpg, sess, private);
-		if (rc) {
-			transport_free_session(sess);
-			return ERR_PTR(rc);
-		}
+		rc = callback(tpg, sess, private);
+		if (rc)
+			goto free_sess;
 	}
 
 	transport_register_session(tpg, sess->se_node_acl, sess, private);
 	return sess;
+
+free_sess:
+	transport_free_session(sess);
+free_cnt:
+	target_free_cmd_counter(cmd_cnt);
+	return ERR_PTR(rc);
 }
 EXPORT_SYMBOL(target_setup_session);
 
@@ -632,7 +630,8 @@ void transport_free_session(struct se_session *se_sess)
 		sbitmap_queue_free(&se_sess->sess_tag_pool);
 		kvfree(se_sess->sess_cmd_map);
 	}
-	transport_uninit_session(se_sess);
+	if (se_sess->cmd_cnt)
+		target_free_cmd_counter(se_sess->cmd_cnt);
 	kmem_cache_free(se_sess_cache, se_sess);
 }
 EXPORT_SYMBOL(transport_free_session);