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authorAlex Elder <elder@inktank.com>2013-04-05 14:46:01 -0500
committerSage Weil <sage@inktank.com>2013-05-01 21:18:33 -0700
commitca8b3a69174b04376722672d7dd6b666a7f17c50 (patch)
tree68c78a604897ae23ff10d971d511b8e2690e2f58 /net/ceph
parent5240d9f95dfe0f0701b35fbff1cb5b70825ad23f (diff)
libceph: implement multiple data items in a message
This patch adds support to the messenger for more than one data item in its data list. A message data cursor has two more fields to support this: - a count of the number of bytes left to be consumed across all data items in the list, "total_resid" - a pointer to the head of the list (for validation only) The cursor initialization routine has been split into two parts: the outer one, which initializes the cursor for traversing the entire list of data items; and the inner one, which initializes the cursor to start processing a single data item. When a message cursor is first initialized, the outer initialization routine sets total_resid to the length provided. The data pointer is initialized to the first data item on the list. From there, the inner initialization routine finishes by setting up to process the data item the cursor points to. Advancing the cursor consumes bytes in total_resid. If the resid field reaches zero, it means the current data item is fully consumed. If total_resid indicates there is more data, the cursor is advanced to point to the next data item, and then the inner initialization routine prepares for using that. (A check is made at this point to make sure we don't wrap around the front of the list.) The type-specific init routines are modified so they can be given a length that's larger than what the data item can support. The resid field is initialized to the smaller of the provided length and the length of the entire data item. When total_resid reaches zero, we're done. This resolves: http://tracker.ceph.com/issues/3761 Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Diffstat (limited to 'net/ceph')
-rw-r--r--net/ceph/messenger.c48
1 files changed, 32 insertions, 16 deletions
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 8bfe7d34bc85..84703e550c26 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -734,7 +734,7 @@ static void ceph_msg_data_bio_cursor_init(struct ceph_msg_data_cursor *cursor,
BUG_ON(!bio);
BUG_ON(!bio->bi_vcnt);
- cursor->resid = length;
+ cursor->resid = min(length, data->bio_length);
cursor->bio = bio;
cursor->vector_index = 0;
cursor->vector_offset = 0;
@@ -833,9 +833,8 @@ static void ceph_msg_data_pages_cursor_init(struct ceph_msg_data_cursor *cursor,
BUG_ON(!data->pages);
BUG_ON(!data->length);
- BUG_ON(length > data->length); /* short reads are OK */
- cursor->resid = length;
+ cursor->resid = min(length, data->length);
page_count = calc_pages_for(data->alignment, (u64)data->length);
cursor->page_offset = data->alignment & ~PAGE_MASK;
cursor->page_index = 0;
@@ -904,7 +903,6 @@ ceph_msg_data_pagelist_cursor_init(struct ceph_msg_data_cursor *cursor,
pagelist = data->pagelist;
BUG_ON(!pagelist);
- BUG_ON(length > pagelist->length); /* short reads are OK */
if (!length)
return; /* pagelist can be assigned but empty */
@@ -912,7 +910,7 @@ ceph_msg_data_pagelist_cursor_init(struct ceph_msg_data_cursor *cursor,
BUG_ON(list_empty(&pagelist->head));
page = list_first_entry(&pagelist->head, struct page, lru);
- cursor->resid = length;
+ cursor->resid = min(length, pagelist->length);
cursor->page = page;
cursor->offset = 0;
cursor->last_piece = length <= PAGE_SIZE;
@@ -982,13 +980,10 @@ static bool ceph_msg_data_pagelist_advance(struct ceph_msg_data_cursor *cursor,
* 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 *msg, size_t length)
+static void __ceph_msg_data_cursor_init(struct ceph_msg_data_cursor *cursor)
{
- struct ceph_msg_data_cursor *cursor = &msg->cursor;
- struct ceph_msg_data *data;
+ size_t length = cursor->total_resid;
- data = list_first_entry(&msg->data, struct ceph_msg_data, links);
- cursor->data = data;
switch (cursor->data->type) {
case CEPH_MSG_DATA_PAGELIST:
ceph_msg_data_pagelist_cursor_init(cursor, length);
@@ -1009,6 +1004,25 @@ static void ceph_msg_data_cursor_init(struct ceph_msg *msg, size_t length)
cursor->need_crc = true;
}
+static void ceph_msg_data_cursor_init(struct ceph_msg *msg, size_t length)
+{
+ struct ceph_msg_data_cursor *cursor = &msg->cursor;
+ struct ceph_msg_data *data;
+
+ BUG_ON(!length);
+ BUG_ON(length > msg->data_length);
+ BUG_ON(list_empty(&msg->data));
+
+ data = list_first_entry(&msg->data, struct ceph_msg_data, links);
+
+ cursor->data_head = &msg->data;
+ cursor->total_resid = length;
+ data = list_first_entry(&msg->data, struct ceph_msg_data, links);
+ cursor->data = data;
+
+ __ceph_msg_data_cursor_init(cursor);
+}
+
/*
* Return the page containing the next piece to process for a given
* data item, and supply the page offset and length of that piece.
@@ -1073,8 +1087,16 @@ static bool ceph_msg_data_advance(struct ceph_msg_data_cursor *cursor,
BUG();
break;
}
+ cursor->total_resid -= bytes;
cursor->need_crc = new_piece;
+ if (!cursor->resid && cursor->total_resid) {
+ WARN_ON(!cursor->last_piece);
+ BUG_ON(list_is_last(&cursor->data->links, cursor->data_head));
+ cursor->data = list_entry_next(cursor->data, links);
+ __ceph_msg_data_cursor_init(cursor);
+ }
+
return new_piece;
}
@@ -2990,8 +3012,6 @@ void ceph_msg_data_set_pages(struct ceph_msg *msg, struct page **pages,
BUG_ON(!pages);
BUG_ON(!length);
- BUG_ON(msg->data_length);
- BUG_ON(!list_empty(&msg->data));
data = ceph_msg_data_create(CEPH_MSG_DATA_PAGES);
BUG_ON(!data);
@@ -3012,8 +3032,6 @@ void ceph_msg_data_set_pagelist(struct ceph_msg *msg,
BUG_ON(!pagelist);
BUG_ON(!pagelist->length);
- BUG_ON(msg->data_length);
- BUG_ON(!list_empty(&msg->data));
data = ceph_msg_data_create(CEPH_MSG_DATA_PAGELIST);
BUG_ON(!data);
@@ -3031,8 +3049,6 @@ void ceph_msg_data_set_bio(struct ceph_msg *msg, struct bio *bio,
struct ceph_msg_data *data;
BUG_ON(!bio);
- BUG_ON(msg->data_length);
- BUG_ON(!list_empty(&msg->data));
data = ceph_msg_data_create(CEPH_MSG_DATA_BIO);
BUG_ON(!data);

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