CIFS: When sending data on socket, pass the correct page offset

It's possible that the offset is non-zero in the page to send, change the
function to pass this offset to socket.
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/transport.c

@@ -288,15 +288,13 @@ __smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 
 	/* now walk the page array and send each page in it */
 	for (i = 0; i < rqst->rq_npages; i++) {
-		size_t len = i == rqst->rq_npages - 1
-				? rqst->rq_tailsz
-				: rqst->rq_pagesz;
-		struct bio_vec bvec = {
-			.bv_page = rqst->rq_pages[i],
-			.bv_len = len
-		};
+		struct bio_vec bvec;
+
+		bvec.bv_page = rqst->rq_pages[i];
+		rqst_page_get_length(rqst, i, &bvec.bv_len, &bvec.bv_offset);
+
 		iov_iter_bvec(&smb_msg.msg_iter, WRITE | ITER_BVEC,
-			      &bvec, 1, len);
+			      &bvec, 1, bvec.bv_len);
 		rc = smb_send_kvec(server, &smb_msg, &sent);
 		if (rc < 0)
 			break;