!422 iscsi bugfixes backport

Merge Pull Request from: @LiuYongQiang0816 
 
two iscsi bugfixes backport from Zhong Jinghua 
 
Link:https://gitee.com/openeuler/kernel/pulls/422 

Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com> 
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> 

drivers/scsi/iscsi_tcp.c

@@ -783,7 +783,7 @@ static int iscsi_sw_tcp_host_get_param(struct Scsi_Host *shost,
 				       enum iscsi_host_param param, char *buf)
 {
 	struct iscsi_sw_tcp_host *tcp_sw_host = iscsi_host_priv(shost);
-	struct iscsi_session *session = tcp_sw_host->session;
+	struct iscsi_session *session;
 	struct iscsi_conn *conn;
 	struct iscsi_tcp_conn *tcp_conn;
 	struct iscsi_sw_tcp_conn *tcp_sw_conn;
@@ -792,6 +792,7 @@ static int iscsi_sw_tcp_host_get_param(struct Scsi_Host *shost,
 
 	switch (param) {
 	case ISCSI_HOST_PARAM_IPADDRESS:
+		session = tcp_sw_host->session;
 		if (!session)
 			return -ENOTCONN;
 
@@ -886,11 +887,13 @@ iscsi_sw_tcp_session_create(struct iscsi_endpoint *ep, uint16_t cmds_max,
 	if (!cls_session)
 		goto remove_host;
 	session = cls_session->dd_data;
-	tcp_sw_host = iscsi_host_priv(shost);
-	tcp_sw_host->session = session;
 
 	if (iscsi_tcp_r2tpool_alloc(session))
 		goto remove_session;
+
+	/* We are now fully setup so expose the session to sysfs. */
+	tcp_sw_host = iscsi_host_priv(shost);
+	tcp_sw_host->session = session;
 	return cls_session;
 
 remove_session:
@@ -910,10 +913,17 @@ static void iscsi_sw_tcp_session_destroy(struct iscsi_cls_session *cls_session)
 	if (WARN_ON_ONCE(session->leadconn))
 		return;
 
+	iscsi_session_remove(cls_session);
+	/*
+	 * Our get_host_param needs to access the session, so remove the
+	 * host from sysfs before freeing the session to make sure userspace
+	 * is no longer accessing the callout.
+	 */
+	iscsi_host_remove(shost);
+
 	iscsi_tcp_r2tpool_free(cls_session->dd_data);
-	iscsi_session_teardown(cls_session);
 
-	iscsi_host_remove(shost);
+	iscsi_session_free(cls_session);
 	iscsi_host_free(shost);
 }
 

drivers/scsi/libiscsi.c

@@ -3018,20 +3018,34 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
 }
 EXPORT_SYMBOL_GPL(iscsi_session_setup);
 
+/*
+ * issi_session_remove - Remove session from iSCSI class.
+ */
+void iscsi_session_remove(struct iscsi_cls_session *cls_session)
+{
+	struct iscsi_session *session = cls_session->dd_data;
+	struct Scsi_Host *shost = session->host;
+
+	iscsi_remove_session(cls_session);
+	/*
+	 * host removal only has to wait for its children to be removed from
+	 * sysfs, and iscsi_tcp needs to do iscsi_host_remove before freeing
+	 * the session, so drop the session count here.
+	 */
+	iscsi_host_dec_session_cnt(shost);
+}
+EXPORT_SYMBOL_GPL(iscsi_session_remove);
+
 /**
- * iscsi_session_teardown - destroy session, host, and cls_session
+ * iscsi_session_free - Free iscsi session and it's resources
  * @cls_session: iscsi session
  */
-void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
+void iscsi_session_free(struct iscsi_cls_session *cls_session)
 {
 	struct iscsi_session *session = cls_session->dd_data;
 	struct module *owner = cls_session->transport->owner;
-	struct Scsi_Host *shost = session->host;
 
 	iscsi_pool_free(&session->cmdpool);
-
-	iscsi_remove_session(cls_session);
-
 	kfree(session->password);
 	kfree(session->password_in);
 	kfree(session->username);
@@ -3047,10 +3061,19 @@ void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
 	kfree(session->discovery_parent_type);
 
 	iscsi_free_session(cls_session);
-
-	iscsi_host_dec_session_cnt(shost);
 	module_put(owner);
 }
+EXPORT_SYMBOL_GPL(iscsi_session_free);
+
+/**
+ * iscsi_session_teardown - destroy session and cls_session
+ * @cls_session: iscsi session
+ */
+void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
+{
+	iscsi_session_remove(cls_session);
+	iscsi_session_free(cls_session);
+}
 EXPORT_SYMBOL_GPL(iscsi_session_teardown);
 
 /**

include/scsi/libiscsi.h

@@ -425,6 +425,8 @@ extern int iscsi_host_get_max_scsi_cmds(struct Scsi_Host *shost,
 extern struct iscsi_cls_session *
 iscsi_session_setup(struct iscsi_transport *, struct Scsi_Host *shost,
 		    uint16_t, int, int, uint32_t, unsigned int);
+void iscsi_session_remove(struct iscsi_cls_session *cls_session);
+void iscsi_session_free(struct iscsi_cls_session *cls_session);
 extern void iscsi_session_teardown(struct iscsi_cls_session *);
 extern void iscsi_session_recovery_timedout(struct iscsi_cls_session *);
 extern int iscsi_set_param(struct iscsi_cls_conn *cls_conn,