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author | Alex Elder <elder@inktank.com> | 2013-03-12 08:34:23 +0400 |
---|---|---|
committer | Sage Weil <sage@inktank.com> | 2013-05-02 08:17:25 +0400 |
commit | 463207aa40cf2cadcae84866b3f85ccaa7022ee8 (patch) | |
tree | 34a5cddfa662036377cea580682303dbc8d4070c /net/ceph/messenger.c | |
parent | 25aff7c559c8b54a810bc094d59fe037cfed6b18 (diff) | |
download | linux-463207aa40cf2cadcae84866b3f85ccaa7022ee8.tar.xz |
libceph: use cursor for bio reads
Replace the use of the information in con->in_msg_pos for incoming
bio data. The old in_msg_pos and the new cursor mechanism do
basically the same thing, just slightly differently.
The main functional difference is that in_msg_pos keeps track of the
length of the complete bio list, and assumed it was fully consumed
when that many bytes had been transferred. The cursor does not assume
a length, it simply consumes all bytes in the bio list. Because the
only user of bio data is the rbd client, and because the length of a
bio list provided by rbd client always matches the number of bytes
in the list, both ways of tracking length are equivalent.
In addition, for in_msg_pos the initial bio vector is selected as
the initial value of the bio->bi_idx, while the cursor assumes this
is zero. Again, the rbd client always passes 0 as the initial index
so the effect is the same.
Other than that, they basically match:
in_msg_pos cursor
---------- ------
bio_iter bio
bio_seg vec_index
page_pos page_offset
The in_msg_pos field is initialized by a call to init_bio_iter().
The bio cursor is initialized by ceph_msg_data_cursor_init().
Both now happen in the same spot, in prepare_message_data().
The in_msg_pos field is advanced by a call to in_msg_pos_next(),
which updates page_pos and calls iter_bio_next() to move to the next
bio vector, or to the next bio in the list. The cursor is advanced
by ceph_msg_data_advance(). That isn't currently happening so
add a call to that in in_msg_pos_next().
Finally, the next piece of data to use for a read is determined
by a bunch of lines in read_partial_message_bio(). Those can be
replaced by an equivalent ceph_msg_data_bio_next() call.
This partially resolves:
http://tracker.ceph.com/issues/4428
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Diffstat (limited to 'net/ceph/messenger.c')
-rw-r--r-- | net/ceph/messenger.c | 17 |
1 files changed, 6 insertions, 11 deletions
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index 0ac4f6cb7339..c795d46d7d4b 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -1468,6 +1468,10 @@ static void in_msg_pos_next(struct ceph_connection *con, size_t len, msg_pos->data_pos += received; msg_pos->page_pos += received; +#ifdef CONFIG_BLOCK + if (ceph_msg_has_bio(msg)) + (void) ceph_msg_data_advance(&msg->b, received); +#endif /* CONFIG_BLOCK */ if (received < len) return; @@ -2255,23 +2259,14 @@ static int read_partial_message_bio(struct ceph_connection *con, unsigned int data_len, bool do_datacrc) { struct ceph_msg *msg = con->in_msg; - struct ceph_msg_pos *msg_pos = &con->in_msg_pos; - struct bio_vec *bv; struct page *page; size_t page_offset; size_t length; - unsigned int left; int ret; BUG_ON(!msg); - BUG_ON(!msg->b.bio_iter); - bv = bio_iovec_idx(msg->b.bio_iter, msg->b.bio_seg); - page = bv->bv_page; - page_offset = bv->bv_offset + msg_pos->page_pos; - BUG_ON(msg_pos->data_pos >= data_len); - left = data_len - msg_pos->data_pos; - BUG_ON(msg_pos->page_pos >= bv->bv_len); - length = min_t(unsigned int, bv->bv_len - msg_pos->page_pos, left); + + page = ceph_msg_data_next(&msg->b, &page_offset, &length, NULL); ret = ceph_tcp_recvpage(con->sock, page, page_offset, length); if (ret <= 0) |