cifs: add pdu_size to the TCP_Server_Info structure

and get rid of some get_rfc1002_length() in smb2

Signed-off-by: Ronnie Sahlberg <[e-mail]>
Signed-off-by: Steve French <[e-mail]>
Reviewed-by: Pavel Shilovsky <[e-mail]>

fs/cifs/cifsglob.h

···
 	struct delayed_work	echo; /* echo ping workqueue job */
 	char	*smallbuf;	/* pointer to current "small" buffer */
 	char	*bigbuf;	/* pointer to current "big" buffer */
+	/* Total size of this PDU. Only valid from cifs_demultiplex_thread */
+	unsigned int pdu_size;
 	unsigned int total_read; /* total amount of data read in this pass */
 #ifdef CONFIG_CIFS_FSCACHE
 	struct fscache_cookie   *fscache; /* client index cache cookie */

fs/cifs/cifssmb.c

···
 	unsigned int data_offset, data_len;
 	struct cifs_readdata *rdata = mid->callback_data;
 	char *buf = server->smallbuf;
-	unsigned int buflen = get_rfc1002_length(buf) +
+	unsigned int buflen = server->pdu_size +
 		server->vals->header_preamble_size;
 	bool use_rdma_mr = false;
 

fs/cifs/connect.c

···
 {
 	int length;
 	char *buf = server->smallbuf;
-	unsigned int pdu_length = get_rfc1002_length(buf);
+	unsigned int pdu_length = server->pdu_size;
 
 	/* make sure this will fit in a large buffer */
 	if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server) -
···
 		 * so we can now interpret the length field.
 		 */
 		pdu_length = get_rfc1002_length(buf);
+		server->pdu_size = pdu_length;
 
 		cifs_dbg(FYI, "RFC1002 header 0x%x\n", pdu_length);
 		if (!is_smb_response(server, buf[0]))

fs/cifs/smb2ops.c

···
 	unsigned int npages;
 	struct page **pages;
 	unsigned int len;
-	unsigned int buflen = get_rfc1002_length(buf) + server->vals->header_preamble_size;
+	unsigned int buflen = server->pdu_size + server->vals->header_preamble_size;
 	int rc;
 	int i = 0;
 
···
 {
 	int length;
 	char *buf = server->smallbuf;
-	unsigned int pdu_length = get_rfc1002_length(buf);
+	unsigned int pdu_length = server->pdu_size;
 	unsigned int buf_size;
 	struct mid_q_entry *mid_entry;
 
···
 smb3_receive_transform(struct TCP_Server_Info *server, struct mid_q_entry **mid)
 {
 	char *buf = server->smallbuf;
-	unsigned int pdu_length = get_rfc1002_length(buf);
+	unsigned int pdu_length = server->pdu_size;
 	struct smb2_transform_hdr *tr_hdr = (struct smb2_transform_hdr *)buf;
 	unsigned int orig_len = le32_to_cpu(tr_hdr->OriginalMessageSize);
 
···
 {
 	char *buf = server->large_buf ? server->bigbuf : server->smallbuf;
 
-	return handle_read_data(server, mid, buf, get_rfc1002_length(buf) +
+	return handle_read_data(server, mid, buf, server->pdu_size +
 				server->vals->header_preamble_size,
 				NULL, 0, 0);
 }