ksmbd: Fix the missing xa_store error check

xa_store() can fail, it return xa_err(-EINVAL) if the entry cannot
be stored in an XArray, or xa_err(-ENOMEM) if memory allocation failed,
so check error for xa_store() to fix it.

Cc: stable@vger.kernel.org
Fixes: b685757 ("ksmbd: Implements sess->rpc_handle_list as xarray")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: ruanjinjie-eng

fs/smb/server/mgmt/user_session.c

@@ -90,7 +90,7 @@ static int __rpc_method(char *rpc_name)
 
 int ksmbd_session_rpc_open(struct ksmbd_session *sess, char *rpc_name)
 {
-	struct ksmbd_session_rpc *entry;
+	struct ksmbd_session_rpc *entry, *old;
 	struct ksmbd_rpc_command *resp;
 	int method;
 
@@ -106,16 +106,19 @@ int ksmbd_session_rpc_open(struct ksmbd_session *sess, char *rpc_name)
 	entry->id = ksmbd_ipc_id_alloc();
 	if (entry->id < 0)
 		goto free_entry;
-	xa_store(&sess->rpc_handle_list, entry->id, entry, GFP_KERNEL);
+	old = xa_store(&sess->rpc_handle_list, entry->id, entry, GFP_KERNEL);
+	if (xa_is_err(old))
+		goto free_id;
 
 	resp = ksmbd_rpc_open(sess, entry->id);
 	if (!resp)
-		goto free_id;
+		goto erase_xa;
 
 	kvfree(resp);
 	return entry->id;
-free_id:
+erase_xa:
 	xa_erase(&sess->rpc_handle_list, entry->id);
+free_id:
 	ksmbd_rpc_id_free(entry->id);
 free_entry:
 	kfree(entry);