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libceph: prepare for other message data item types

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This just inserts some infrastructure in preparation for handling
other types of ceph message data items.  No functional changes,
just trying to simplify review by separating out some noise.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This commit is contained in:
Alex Elder 2013-03-06 23:39:39 -06:00 committed by Sage Weil
parent fe38a2b67b
commit dd236fcb65
2 changed files with 99 additions and 26 deletions
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8
include/linux/ceph/messenger.h
View File

@ -97,8 +97,12 @@ static __inline__ bool ceph_msg_data_type_valid(enum ceph_msg_data_type type)
struct ceph_msg_data_cursor {
bool last_piece; /* now at last piece of data item */
struct page *page; /* current page in pagelist */
size_t offset; /* pagelist bytes consumed */
union {
struct { /* pagelist */
struct page *page; /* page from list */
size_t offset; /* bytes from list */
};
};
};
struct ceph_msg_data {

117
net/ceph/messenger.c
View File

@ -742,21 +742,16 @@ static void iter_bio_next(struct bio **bio_iter, unsigned int *seg)
#endif
/*
* Message data is handled (sent or received) in pieces, where each
* piece resides on a single page. The network layer might not
* consume an entire piece at once. A data item's cursor keeps
* track of which piece is next to process and how much remains to
* be processed in that piece. It also tracks whether the current
* piece is the last one in the data item.
* For a pagelist, a piece is whatever remains to be consumed in the
* first page in the list, or the front of the next page.
*/
static void ceph_msg_data_cursor_init(struct ceph_msg_data *data)
static void ceph_msg_data_pagelist_cursor_init(struct ceph_msg_data *data)
{
struct ceph_msg_data_cursor *cursor = &data->cursor;
struct ceph_pagelist *pagelist;
struct page *page;
if (data->type != CEPH_MSG_DATA_PAGELIST)
return;
BUG_ON(data->type != CEPH_MSG_DATA_PAGELIST);
pagelist = data->pagelist;
BUG_ON(!pagelist);
@ -771,15 +766,9 @@ static void ceph_msg_data_cursor_init(struct ceph_msg_data *data)
cursor->last_piece = pagelist->length <= PAGE_SIZE;
}
/*
* Return the page containing the next piece to process for a given
* data item, and supply the page offset and length of that piece.
* Indicate whether this is the last piece in this data item.
*/
static struct page *ceph_msg_data_next(struct ceph_msg_data *data,
static struct page *ceph_msg_data_pagelist_next(struct ceph_msg_data *data,
size_t *page_offset,
size_t *length,
bool *last_piece)
size_t *length)
{
struct ceph_msg_data_cursor *cursor = &data->cursor;
struct ceph_pagelist *pagelist;
@ -793,8 +782,7 @@ static struct page *ceph_msg_data_next(struct ceph_msg_data *data,
BUG_ON(!cursor->page);
BUG_ON(cursor->offset >= pagelist->length);
*last_piece = cursor->last_piece;
if (*last_piece) {
if (cursor->last_piece) {
/* pagelist offset is always 0 */
piece_end = pagelist->length & ~PAGE_MASK;
if (!piece_end)
@ -808,11 +796,8 @@ static struct page *ceph_msg_data_next(struct ceph_msg_data *data,
return data->cursor.page;
}
/*
* Returns true if the result moves the cursor on to the next piece
* (the next page) of the pagelist.
*/
static bool ceph_msg_data_advance(struct ceph_msg_data *data, size_t bytes)
static bool ceph_msg_data_pagelist_advance(struct ceph_msg_data *data,
size_t bytes)
{
struct ceph_msg_data_cursor *cursor = &data->cursor;
struct ceph_pagelist *pagelist;
@ -844,6 +829,90 @@ static bool ceph_msg_data_advance(struct ceph_msg_data *data, size_t bytes)
return true;
}
/*
* Message data is handled (sent or received) in pieces, where each
* piece resides on a single page. The network layer might not
* consume an entire piece at once. A data item's cursor keeps
* track of which piece is next to process and how much remains to
* be processed in that piece. It also tracks whether the current
* piece is the last one in the data item.
*/
static void ceph_msg_data_cursor_init(struct ceph_msg_data *data)
{
switch (data->type) {
case CEPH_MSG_DATA_PAGELIST:
ceph_msg_data_pagelist_cursor_init(data);
break;
case CEPH_MSG_DATA_NONE:
case CEPH_MSG_DATA_PAGES:
#ifdef CONFIG_BLOCK
case CEPH_MSG_DATA_BIO:
#endif /* CONFIG_BLOCK */
default:
/* BUG(); */
break;
}
}
/*
* Return the page containing the next piece to process for a given
* data item, and supply the page offset and length of that piece.
* Indicate whether this is the last piece in this data item.
*/
static struct page *ceph_msg_data_next(struct ceph_msg_data *data,
size_t *page_offset,
size_t *length,
bool *last_piece)
{
struct page *page;
switch (data->type) {
case CEPH_MSG_DATA_PAGELIST:
page = ceph_msg_data_pagelist_next(data, page_offset, length);
break;
case CEPH_MSG_DATA_NONE:
case CEPH_MSG_DATA_PAGES:
#ifdef CONFIG_BLOCK
case CEPH_MSG_DATA_BIO:
#endif /* CONFIG_BLOCK */
default:
page = NULL;
break;
}
BUG_ON(!page);
BUG_ON(*page_offset + *length > PAGE_SIZE);
BUG_ON(!*length);
if (last_piece)
*last_piece = data->cursor.last_piece;
return page;
}
/*
* Returns true if the result moves the cursor on to the next piece
* of the data item.
*/
static bool ceph_msg_data_advance(struct ceph_msg_data *data, size_t bytes)
{
bool new_piece;
switch (data->type) {
case CEPH_MSG_DATA_PAGELIST:
new_piece = ceph_msg_data_pagelist_advance(data, bytes);
break;
case CEPH_MSG_DATA_NONE:
case CEPH_MSG_DATA_PAGES:
#ifdef CONFIG_BLOCK
case CEPH_MSG_DATA_BIO:
#endif /* CONFIG_BLOCK */
default:
BUG();
break;
}
return new_piece;
}
static void prepare_message_data(struct ceph_msg *msg,
struct ceph_msg_pos *msg_pos)
{