diff --git a/fs/smb/client/smb1misc.c b/fs/smb/client/smb1misc.c
index ba56023010d8..cdfbbff24b72 100644
--- a/fs/smb/client/smb1misc.c
+++ b/fs/smb/client/smb1misc.c
@@ -80,7 +80,8 @@ is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 			(struct smb_com_transaction_change_notify_rsp *)buf;
 		struct file_notify_information *pnotify;
 		__u32 data_offset = 0;
-		size_t len = srv->total_read - srv->pdu_size;
+		/* total_read excludes the RFC1002 preamble */
+		size_t len = srv->total_read;
 
 		if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 			data_offset = le32_to_cpu(pSMBr->DataOffset);