libceph: abstract message data
Group the types of message data into an abstract structure with a
type indicator and a union containing fields appropriate to the
type of data it represents. Use this to represent the pages,
pagelist, bio, and trail in a ceph message.
Verify message data is of type NONE in ceph_msg_data_set_*()
routines. Since information about message data of type NONE really
should not be interpreted, get rid of the other assertions in those
functions.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index f485455..f256b4b 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -1054,7 +1054,7 @@
msg_pos->did_page_crc = false;
if (in_trail) {
BUG_ON(!ceph_msg_has_trail(msg));
- list_rotate_left(&msg->t.trail->head);
+ list_rotate_left(&msg->t.pagelist->head);
} else if (ceph_msg_has_pagelist(msg)) {
list_rotate_left(&msg->l.pagelist->head);
#ifdef CONFIG_BLOCK
@@ -1120,7 +1120,7 @@
size_t trail_off = data_len;
if (ceph_msg_has_trail(msg)) {
- trail_len = msg->t.trail->length;
+ trail_len = msg->t.pagelist->length;
trail_off -= trail_len;
}
@@ -1149,7 +1149,7 @@
if (in_trail) {
BUG_ON(!ceph_msg_has_trail(msg));
total_max_write = data_len - msg_pos->data_pos;
- page = list_first_entry(&msg->t.trail->head,
+ page = list_first_entry(&msg->t.pagelist->head,
struct page, lru);
} else if (ceph_msg_has_pages(msg)) {
page = msg->p.pages[msg_pos->page];
@@ -2736,14 +2736,19 @@
}
EXPORT_SYMBOL(ceph_con_keepalive);
+static void ceph_msg_data_init(struct ceph_msg_data *data)
+{
+ data->type = CEPH_MSG_DATA_NONE;
+}
+
void ceph_msg_data_set_pages(struct ceph_msg *msg, struct page **pages,
size_t length, size_t alignment)
{
BUG_ON(!pages);
BUG_ON(!length);
- BUG_ON(msg->p.pages);
- BUG_ON(msg->p.length);
+ BUG_ON(msg->p.type != CEPH_MSG_DATA_NONE);
+ msg->p.type = CEPH_MSG_DATA_PAGES;
msg->p.pages = pages;
msg->p.length = length;
msg->p.alignment = alignment & ~PAGE_MASK;
@@ -2755,8 +2760,9 @@
{
BUG_ON(!pagelist);
BUG_ON(!pagelist->length);
- BUG_ON(msg->l.pagelist);
+ BUG_ON(msg->l.type != CEPH_MSG_DATA_NONE);
+ msg->l.type = CEPH_MSG_DATA_PAGELIST;
msg->l.pagelist = pagelist;
}
EXPORT_SYMBOL(ceph_msg_data_set_pagelist);
@@ -2764,8 +2770,9 @@
void ceph_msg_data_set_bio(struct ceph_msg *msg, struct bio *bio)
{
BUG_ON(!bio);
- BUG_ON(msg->b.bio);
+ BUG_ON(msg->b.type != CEPH_MSG_DATA_NONE);
+ msg->b.type = CEPH_MSG_DATA_BIO;
msg->b.bio = bio;
}
EXPORT_SYMBOL(ceph_msg_data_set_bio);
@@ -2774,9 +2781,10 @@
{
BUG_ON(!trail);
BUG_ON(!trail->length);
- BUG_ON(msg->t.trail);
+ BUG_ON(msg->b.type != CEPH_MSG_DATA_NONE);
- msg->t.trail = trail;
+ msg->t.type = CEPH_MSG_DATA_PAGELIST;
+ msg->t.pagelist = trail;
}
EXPORT_SYMBOL(ceph_msg_data_set_trail);
@@ -2800,6 +2808,11 @@
INIT_LIST_HEAD(&m->list_head);
kref_init(&m->kref);
+ ceph_msg_data_init(&m->p);
+ ceph_msg_data_init(&m->l);
+ ceph_msg_data_init(&m->b);
+ ceph_msg_data_init(&m->t);
+
/* front */
m->front_max = front_len;
if (front_len) {
@@ -2965,7 +2978,7 @@
}
if (ceph_msg_has_trail(m))
- m->t.trail = NULL;
+ m->t.pagelist = NULL;
if (m->pool)
ceph_msgpool_put(m->pool, m);