From 7fe1e5e57b84eab98ff352519aa66e86dac5bf61 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Wed, 6 Mar 2013 23:39:39 -0600 Subject: [PATCH] libceph: use data cursor for message pagelist Switch to using the message cursor for the (non-trail) outgoing pagelist data item in a message if present. Notes on the logic changes in out_msg_pos_next(): - only the mds client uses a ceph pagelist for message data; - if the mds client ever uses a pagelist, it never uses a page array (or anything else, for that matter) for data in the same message; - only the osd client uses the trail portion of a message data, and when it does, it never uses any other data fields for outgoing data in the same message; and finally - only the rbd client uses bio message data (never pagelist). Therefore out_msg_pos_next() can assume: - if we're in the trail portion of a message, the message data pagelist, data, and bio can be ignored; and - if there is a page list, there will never be any a bio or page array data, and vice-versa. Signed-off-by: Alex Elder Reviewed-by: Josh Durgin --- net/ceph/messenger.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index 4cc27a136e35..30c8792be180 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -931,8 +931,10 @@ static void prepare_message_data(struct ceph_msg *msg, #endif msg_pos->data_pos = 0; - /* If there's a trail, initialize its cursor */ + /* Initialize data cursors */ + if (ceph_msg_has_pagelist(msg)) + ceph_msg_data_cursor_init(&msg->l); if (ceph_msg_has_trail(msg)) ceph_msg_data_cursor_init(&msg->t); @@ -1220,18 +1222,19 @@ static void out_msg_pos_next(struct ceph_connection *con, struct page *page, { struct ceph_msg *msg = con->out_msg; struct ceph_msg_pos *msg_pos = &con->out_msg_pos; + bool need_crc = false; BUG_ON(!msg); BUG_ON(!sent); msg_pos->data_pos += sent; msg_pos->page_pos += sent; - if (in_trail) { - bool need_crc; - + if (in_trail) need_crc = ceph_msg_data_advance(&msg->t, sent); - BUG_ON(need_crc && sent != len); - } + else if (ceph_msg_has_pagelist(msg)) + need_crc = ceph_msg_data_advance(&msg->l, sent); + BUG_ON(need_crc && sent != len); + if (sent < len) return; @@ -1239,13 +1242,10 @@ static void out_msg_pos_next(struct ceph_connection *con, struct page *page, msg_pos->page_pos = 0; msg_pos->page++; msg_pos->did_page_crc = false; - if (ceph_msg_has_pagelist(msg)) { - list_rotate_left(&msg->l.pagelist->head); #ifdef CONFIG_BLOCK - } else if (ceph_msg_has_bio(msg)) { + if (ceph_msg_has_bio(msg)) iter_bio_next(&msg->b.bio_iter, &msg->b.bio_seg); #endif - } } static void in_msg_pos_next(struct ceph_connection *con, size_t len, @@ -1340,8 +1340,9 @@ static int write_partial_message_data(struct ceph_connection *con) } else if (ceph_msg_has_pages(msg)) { page = msg->p.pages[msg_pos->page]; } else if (ceph_msg_has_pagelist(msg)) { - page = list_first_entry(&msg->l.pagelist->head, - struct page, lru); + use_cursor = true; + page = ceph_msg_data_next(&msg->l, &page_offset, + &length, &last_piece); #ifdef CONFIG_BLOCK } else if (ceph_msg_has_bio(msg)) { struct bio_vec *bv; -- 2.20.1