cifs: Use help macro to get the header preamble size

It's better to use HEADER_PREAMBLE_SIZE because the unfolded expression
too long. No actual functional changes, minor readability improvement.

Signed-off-by: Zhang Xiaoxu <[e-mail]>
Reviewed-by: Paulo Alcantara (SUSE) <[e-mail]>
Signed-off-by: Steve French <[e-mail]>

fs/cifs/cifsencrypt.c

···
 	int rc;
 	struct kvec *iov = rqst->rq_iov;
 	int n_vec = rqst->rq_nvec;
-	int is_smb2 = server->vals->header_preamble_size == 0;
+	bool is_smb2 = HEADER_PREAMBLE_SIZE(server) == 0;
 
 	/* iov[0] is actual data and not the rfc1002 length for SMB2+ */
 	if (is_smb2) {

fs/cifs/cifsglob.h

···
 
 #define HEADER_SIZE(server) (server->vals->header_size)
 #define MAX_HEADER_SIZE(server) (server->vals->max_header_size)
+#define HEADER_PREAMBLE_SIZE(server) (server->vals->header_preamble_size)
 
 /**
  * CIFS superblock mount flags (mnt_cifs_flags) to consider when

fs/cifs/connect.c

···
 	/*
 	 * SMB1 does not use credits.
 	 */
-	if (server->vals->header_preamble_size)
+	if (HEADER_PREAMBLE_SIZE(server))
 		return 0;
 
 	return le16_to_cpu(shdr->CreditRequest);
···
 
 	/* make sure this will fit in a large buffer */
 	if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server) -
-		server->vals->header_preamble_size) {
+	    HEADER_PREAMBLE_SIZE(server)) {
 		cifs_server_dbg(VFS, "SMB response too long (%u bytes)\n", pdu_length);
 		cifs_reconnect(server, true);
 		return -ECONNABORTED;
···
 
 	/* now read the rest */
 	length = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1,
-				       pdu_length - HEADER_SIZE(server) + 1
-				       + server->vals->header_preamble_size);
+				       pdu_length - HEADER_SIZE(server) + 1 +
+				       HEADER_PREAMBLE_SIZE(server));
 
 	if (length < 0)
 		return length;
···
 	/*
 	 * SMB1 does not use credits.
 	 */
-	if (server->vals->header_preamble_size)
+	if (HEADER_PREAMBLE_SIZE(server))
 		return;
 
 	if (shdr->CreditRequest) {
···
 		if (length < 0)
 			continue;
 
-		if (server->vals->header_preamble_size == 0)
+		if (HEADER_PREAMBLE_SIZE(server) == 0)
 			server->total_read = 0;
 		else
 			server->total_read = length;
···
 
 		/* make sure we have enough to get to the MID */
 		if (server->pdu_size < HEADER_SIZE(server) - 1 -
-		    server->vals->header_preamble_size) {
+		    HEADER_PREAMBLE_SIZE(server)) {
 			cifs_server_dbg(VFS, "SMB response too short (%u bytes)\n",
 				 server->pdu_size);
 			cifs_reconnect(server, true);
···
 
 		/* read down to the MID */
 		length = cifs_read_from_socket(server,
-			     buf + server->vals->header_preamble_size,
-			     HEADER_SIZE(server) - 1
-			     - server->vals->header_preamble_size);
+			     buf + HEADER_PREAMBLE_SIZE(server),
+			     HEADER_SIZE(server) - 1 -
+			     HEADER_PREAMBLE_SIZE(server));
 		if (length < 0)
 			continue;
 		server->total_read += length;

fs/cifs/transport.c

···
 	int nvec;
 	unsigned long buflen = 0;
 
-	if (server->vals->header_preamble_size == 0 &&
-	    rqst->rq_nvec >= 2 && rqst->rq_iov[0].iov_len == 4) {
+	if (HEADER_PREAMBLE_SIZE(server) == 0 && rqst->rq_nvec >= 2 &&
+	    rqst->rq_iov[0].iov_len == 4) {
 		iov = &rqst->rq_iov[1];
 		nvec = rqst->rq_nvec - 1;
 	} else {
···
 	sigprocmask(SIG_BLOCK, &mask, &oldmask);
 
 	/* Generate a rfc1002 marker for SMB2+ */
-	if (server->vals->header_preamble_size == 0) {
+	if (HEADER_PREAMBLE_SIZE(server) == 0) {
 		struct kvec hiov = {
 			.iov_base = &rfc1002_marker,
 			.iov_len  = 4
···
 		buf = (char *)midQ[i]->resp_buf;
 		resp_iov[i].iov_base = buf;
 		resp_iov[i].iov_len = midQ[i]->resp_buf_size +
-			server->vals->header_preamble_size;
+			HEADER_PREAMBLE_SIZE(server);
 
 		if (midQ[i]->large_buf)
 			resp_buf_type[i] = CIFS_LARGE_BUFFER;
···
 cifs_discard_remaining_data(struct TCP_Server_Info *server)
 {
 	unsigned int rfclen = server->pdu_size;
-	int remaining = rfclen + server->vals->header_preamble_size -
+	int remaining = rfclen + HEADER_PREAMBLE_SIZE(server) -
 		server->total_read;
 
 	while (remaining > 0) {
···
 	unsigned int data_offset, data_len;
 	struct cifs_readdata *rdata = mid->callback_data;
 	char *buf = server->smallbuf;
-	unsigned int buflen = server->pdu_size +
-		server->vals->header_preamble_size;
+	unsigned int buflen = server->pdu_size + HEADER_PREAMBLE_SIZE(server);
 	bool use_rdma_mr = false;
 
 	cifs_dbg(FYI, "%s: mid=%llu offset=%llu bytes=%u\n",
···
 
 	/* set up first two iov for signature check and to get credits */
 	rdata->iov[0].iov_base = buf;
-	rdata->iov[0].iov_len = server->vals->header_preamble_size;
-	rdata->iov[1].iov_base = buf + server->vals->header_preamble_size;
+	rdata->iov[0].iov_len = HEADER_PREAMBLE_SIZE(server);
+	rdata->iov[1].iov_base = buf + HEADER_PREAMBLE_SIZE(server);
 	rdata->iov[1].iov_len =
-		server->total_read - server->vals->header_preamble_size;
+		server->total_read - HEADER_PREAMBLE_SIZE(server);
 	cifs_dbg(FYI, "0: iov_base=%p iov_len=%zu\n",
 		 rdata->iov[0].iov_base, rdata->iov[0].iov_len);
 	cifs_dbg(FYI, "1: iov_base=%p iov_len=%zu\n",
···
 	}
 
 	data_offset = server->ops->read_data_offset(buf) +
-		server->vals->header_preamble_size;
+		HEADER_PREAMBLE_SIZE(server);
 	if (data_offset < server->total_read) {
 		/*
 		 * win2k8 sometimes sends an offset of 0 when the read