scsi: target: Fix xcopy sess release leak

transport_init_session can allocate memory via percpu_ref_init, and
target_xcopy_release_pt never frees it. This adds a
transport_uninit_session function to handle cleanup of resources allocated
in the init function.

Link: https://lore.kernel.org/r/1593654203-12442-3-git-send-email-michael.christie@oracle.comSigned-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_internal.h

@@ -138,6 +138,7 @@ int	init_se_kmem_caches(void);
 void	release_se_kmem_caches(void);
 u32	scsi_get_new_index(scsi_index_t);
 void	transport_subsystem_check_init(void);
+void	transport_uninit_session(struct se_session *);
 unsigned char *transport_dump_cmd_direction(struct se_cmd *);
 void	transport_dump_dev_state(struct se_device *, char *, int *);
 void	transport_dump_dev_info(struct se_device *, struct se_lun *,

drivers/target/target_core_transport.c

@@ -236,6 +236,11 @@ int transport_init_session(struct se_session *se_sess)
 }
 EXPORT_SYMBOL(transport_init_session);
 
+void transport_uninit_session(struct se_session *se_sess)
+{
+	percpu_ref_exit(&se_sess->cmd_count);
+}
+
 /**
  * transport_alloc_session - allocate a session object and initialize it
  * @sup_prot_ops: bitmask that defines which T10-PI modes are supported.
@@ -579,7 +584,7 @@ void transport_free_session(struct se_session *se_sess)
 		sbitmap_queue_free(&se_sess->sess_tag_pool);
 		kvfree(se_sess->sess_cmd_map);
 	}
-	percpu_ref_exit(&se_sess->cmd_count);
+	transport_uninit_session(se_sess);
 	kmem_cache_free(se_sess_cache, se_sess);
 }
 EXPORT_SYMBOL(transport_free_session);

drivers/target/target_core_xcopy.c

@@ -474,7 +474,7 @@ int target_xcopy_setup_pt(void)
 	memset(&xcopy_pt_sess, 0, sizeof(struct se_session));
 	ret = transport_init_session(&xcopy_pt_sess);
 	if (ret < 0)
-		return ret;
+		goto destroy_wq;
 
 	xcopy_pt_nacl.se_tpg = &xcopy_pt_tpg;
 	xcopy_pt_nacl.nacl_sess = &xcopy_pt_sess;
@@ -483,12 +483,19 @@ int target_xcopy_setup_pt(void)
 	xcopy_pt_sess.se_node_acl = &xcopy_pt_nacl;
 
 	return 0;
+
+destroy_wq:
+	destroy_workqueue(xcopy_wq);
+	xcopy_wq = NULL;
+	return ret;
 }
 
 void target_xcopy_release_pt(void)
 {
-	if (xcopy_wq)
+	if (xcopy_wq) {
 		destroy_workqueue(xcopy_wq);
+		transport_uninit_session(&xcopy_pt_sess);
+	}
 }
 
 /*