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/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index fb2b18a..5860dd0 100644
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -64,12 +64,55 @@
u32 required_features;
};
-#define ceph_msg_has_pages(m) ((m)->p.pages != NULL)
-#define ceph_msg_has_pagelist(m) ((m)->l.pagelist != NULL)
+#define ceph_msg_has_pages(m) ((m)->p.type == CEPH_MSG_DATA_PAGES)
+#define ceph_msg_has_pagelist(m) ((m)->l.type == CEPH_MSG_DATA_PAGELIST)
#ifdef CONFIG_BLOCK
-#define ceph_msg_has_bio(m) ((m)->b.bio != NULL)
+#define ceph_msg_has_bio(m) ((m)->b.type == CEPH_MSG_DATA_BIO)
#endif /* CONFIG_BLOCK */
-#define ceph_msg_has_trail(m) ((m)->t.trail != NULL)
+#define ceph_msg_has_trail(m) ((m)->t.type == CEPH_MSG_DATA_PAGELIST)
+
+enum ceph_msg_data_type {
+ CEPH_MSG_DATA_NONE, /* message contains no data payload */
+ CEPH_MSG_DATA_PAGES, /* data source/destination is a page array */
+ CEPH_MSG_DATA_PAGELIST, /* data source/destination is a pagelist */
+#ifdef CONFIG_BLOCK
+ CEPH_MSG_DATA_BIO, /* data source/destination is a bio list */
+#endif /* CONFIG_BLOCK */
+};
+
+static __inline__ bool ceph_msg_data_type_valid(enum ceph_msg_data_type type)
+{
+ switch (type) {
+ case CEPH_MSG_DATA_NONE:
+ case CEPH_MSG_DATA_PAGES:
+ case CEPH_MSG_DATA_PAGELIST:
+#ifdef CONFIG_BLOCK
+ case CEPH_MSG_DATA_BIO:
+#endif /* CONFIG_BLOCK */
+ return true;
+ default:
+ return false;
+ }
+}
+
+struct ceph_msg_data {
+ enum ceph_msg_data_type type;
+ union {
+#ifdef CONFIG_BLOCK
+ struct {
+ struct bio *bio_iter; /* iterator */
+ struct bio *bio;
+ unsigned int bio_seg; /* current seg in bio */
+ };
+#endif /* CONFIG_BLOCK */
+ struct {
+ struct page **pages; /* NOT OWNER. */
+ size_t length; /* total # bytes */
+ unsigned int alignment; /* first page */
+ };
+ struct ceph_pagelist *pagelist;
+ };
+};
/*
* a single message. it contains a header (src, dest, message type, etc.),
@@ -83,24 +126,12 @@
struct ceph_buffer *middle;
/* data payload */
- struct {
- struct page **pages; /* NOT OWNER. */
- size_t length; /* # data bytes in array */
- unsigned int alignment; /* first page */
- } p;
- struct {
- struct ceph_pagelist *pagelist;
- } l;
+ struct ceph_msg_data p; /* pages */
+ struct ceph_msg_data l; /* pagelist */
#ifdef CONFIG_BLOCK
- struct {
- struct bio *bio_iter; /* iterator */
- struct bio *bio;
- unsigned int bio_seg; /* current seg in bio */
- } b;
+ struct ceph_msg_data b; /* bio */
#endif /* CONFIG_BLOCK */
- struct {
- struct ceph_pagelist *trail; /* trailing part of data */
- } t;
+ struct ceph_msg_data t; /* trail */
struct ceph_connection *con;
struct list_head list_head; /* links for connection lists */
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);