libceph: kill most of ceph_msg_pos

All but one of the fields in the ceph_msg_pos structure are now
never used (only assigned), so get rid of them.  This allows
several small blocks of code to go away.

This is cleanup of old code related to:
    http://tracker.ceph.com/issues/4428

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

include/linux/ceph/messenger.h

@@ -157,8 +157,6 @@ struct ceph_msg {
 };
 
 struct ceph_msg_pos {
-	int page, page_pos;  /* which page; offset in page */
-	int data_pos;        /* offset in data payload */
 	bool did_page_crc;   /* true if we've calculated crc for current page */
 };
 

net/ceph/messenger.c

@@ -1083,14 +1083,6 @@ static void prepare_message_data(struct ceph_msg *msg,
 	data_len = le32_to_cpu(msg->hdr.data_len);
 	BUG_ON(!data_len);
 
-	/* initialize page iterator */
-	msg_pos->page = 0;
-	if (ceph_msg_has_data(msg))
-		msg_pos->page_pos = msg->data.alignment;
-	else
-		msg_pos->page_pos = 0;
-	msg_pos->data_pos = 0;
-
 	/* Initialize data cursor */
 
 	ceph_msg_data_cursor_init(&msg->data, data_len);
@@ -1402,39 +1394,30 @@ static void out_msg_pos_next(struct ceph_connection *con, struct page *page,
 	BUG_ON(!msg);
 	BUG_ON(!sent);
 
-	msg_pos->data_pos += sent;
-	msg_pos->page_pos += sent;
 	need_crc = ceph_msg_data_advance(&msg->data, sent);
 	BUG_ON(need_crc && sent != len);
 
 	if (sent < len)
 		return;
 
 	BUG_ON(sent != len);
-	msg_pos->page_pos = 0;
-	msg_pos->page++;
 	msg_pos->did_page_crc = false;
 }
 
 static void in_msg_pos_next(struct ceph_connection *con, size_t len,
 				size_t received)
 {
 	struct ceph_msg *msg = con->in_msg;
-	struct ceph_msg_pos *msg_pos = &con->in_msg_pos;
 
 	BUG_ON(!msg);
 	BUG_ON(!received);
 
-	msg_pos->data_pos += received;
-	msg_pos->page_pos += received;
 	(void) ceph_msg_data_advance(&msg->data, received);
 
 	if (received < len)
 		return;
 
 	BUG_ON(received != len);
-	msg_pos->page_pos = 0;
-	msg_pos->page++;
 }
 
 static u32 ceph_crc32c_page(u32 crc, struct page *page,
@@ -1465,8 +1448,7 @@ static int write_partial_message_data(struct ceph_connection *con)
 	bool do_datacrc = !con->msgr->nocrc;
 	int ret;
 
-	dout("%s %p msg %p page %d offset %d\n", __func__,
-	     con, msg, msg_pos->page, msg_pos->page_pos);
+	dout("%s %p msg %p\n", __func__, con, msg);
 
 	if (WARN_ON(!ceph_msg_has_data(msg)))
 		return -EINVAL;
@@ -2159,7 +2141,6 @@ static int read_partial_msg_data(struct ceph_connection *con)
 	struct ceph_msg *msg = con->in_msg;
 	struct ceph_msg_data_cursor *cursor = &msg->data.cursor;
 	const bool do_datacrc = !con->msgr->nocrc;
-	unsigned int data_len;
 	struct page *page;
 	size_t page_offset;
 	size_t length;
@@ -2169,7 +2150,6 @@ static int read_partial_msg_data(struct ceph_connection *con)
 	if (WARN_ON(!ceph_msg_has_data(msg)))
 		return -EIO;
 
-	data_len = le32_to_cpu(con->in_hdr.data_len);
 	while (cursor->resid) {
 		page = ceph_msg_data_next(&msg->data, &page_offset, &length,
 							NULL);