scsi: libiscsi: Add iscsi_cls_conn to sysfs after initialization

mainline inclusion
from mainline-v5.18-rc1
commit 7dae459f
category: bugfix
bugzilla: 187381, https://gitee.com/openeuler/kernel/issues/I5LBBP
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7dae459f5e56a89ab01413ae055595c982713349

--------------------------------

iscsi_create_conn() exposed iscsi_cls_conn to sysfs prior to initialization
of iscsi_conn's dd_data. When userspace tried to access an attribute such
as the connect address, a NULL pointer dereference was observed.

Do not add iscsi_cls_conn to sysfs until it has been initialized.  Remove
iscsi_create_conn() since it is no longer used.

Link: https://lore.kernel.org/r/20220310015759.3296841-3-haowenchao@huawei.comReviewed-by: NMike Christie <michael.christie@oracle.com>
Signed-off-by: NWenchao Hao <haowenchao@huawei.com>
Signed-off-by: NWu Bo <wubo40@huawei.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Conflict: iscsi_create_conn() is not removed
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/scsi/libiscsi.c

@@ -3032,8 +3032,9 @@ iscsi_conn_setup(struct iscsi_cls_session *cls_session, int dd_size,
 	struct iscsi_conn *conn;
 	struct iscsi_cls_conn *cls_conn;
 	char *data;
+	int err;
 
-	cls_conn = iscsi_create_conn(cls_session, sizeof(*conn) + dd_size,
+	cls_conn = iscsi_alloc_conn(cls_session, sizeof(*conn) + dd_size,
 				     conn_idx);
 	if (!cls_conn)
 		return NULL;
@@ -3073,13 +3074,21 @@ iscsi_conn_setup(struct iscsi_cls_session *cls_session, int dd_size,
 
 	init_waitqueue_head(&session->ehwait);
 
+	err = iscsi_add_conn(cls_conn);
+	if (err)
+		goto login_task_add_dev_fail;
+
 	return cls_conn;
 
+login_task_add_dev_fail:
+	free_pages((unsigned long) conn->data,
+		   get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
+
 login_task_data_alloc_fail:
 	kfifo_in(&session->cmdpool.queue, (void*)&conn->login_task,
 		    sizeof(void*));
 login_task_alloc_fail:
-	iscsi_destroy_conn(cls_conn);
+	iscsi_put_conn(cls_conn);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_setup);