[PATCH 13/22] ceph: Convert to immutable biovecs

Kent Overstreet
2013-08-07T21:55:33Z

Now that we've got a mechanism for immutable biovecs -
bi_iter.bi_bvec_done - we need to convert drivers to use primitives that
respect it instead of using the bvec array directly.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sage Weil <sage@inktank.com>
Cc: ceph-devel@vger.kernel.org
---
include/linux/ceph/messenger.h | 4 ++--
net/ceph/messenger.c | 43 +++++++++++++++++-------------------------
2 files changed, 19 insertions(+), 28 deletions(-)

diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index 7c1420b..091fdb6 100644
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -1,6 +1,7 @@
#ifndef __FS_CEPH_MESSENGER_H
#define __FS_CEPH_MESSENGER_H

+#include <linux/blk_types.h>
#include <linux/kref.h>
#include <linux/mutex.h>
#include <linux/net.h>
@@ -119,8 +120,7 @@ struct ceph_msg_data_cursor {
#ifdef CONFIG_BLOCK
struct { /* bio */
struct bio *bio; /* bio from list */
- unsigned int vector_index; /* vector from bio */
- unsigned int vector_offset; /* bytes from vector */
+ struct bvec_iter bvec_iter;
};
#endif /* CONFIG_BLOCK */
struct { /* pages */
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index eb0a46a..86d336e 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -777,13 +777,12 @@ static void ceph_msg_data_bio_cursor_init(struct ceph_msg_data_cursor *cursor,

bio = data->bio;
BUG_ON(!bio);
- BUG_ON(!bio->bi_vcnt);

cursor->resid = min(length, data->bio_length);
cursor->bio = bio;
- cursor->vector_index = 0;
- cursor->vector_offset = 0;
- cursor->last_piece = length <= bio->bi_io_vec[0].bv_len;
+ cursor->bvec_iter = bio->bi_iter;
+ cursor->last_piece =
+ cursor->resid <= bio_iter_len(bio, cursor->bvec_iter);
}

static struct page *ceph_msg_data_bio_next(struct ceph_msg_data_cursor *cursor,
@@ -792,71 +791,63 @@ static struct page *ceph_msg_data_bio_next(struct ceph_msg_data_cursor *cursor,
{
struct ceph_msg_data *data = cursor->data;
struct bio *bio;
- struct bio_vec *bio_vec;
- unsigned int index;
+ struct bio_vec bio_vec;

BUG_ON(data->type != CEPH_MSG_DATA_BIO);

bio = cursor->bio;
BUG_ON(!bio);

- index = cursor->vector_index;
- BUG_ON(index >= (unsigned int) bio->bi_vcnt);
+ bio_vec = bio_iter_iovec(bio, cursor->bvec_iter);

- bio_vec = &bio->bi_io_vec[index];
- BUG_ON(cursor->vector_offset >= bio_vec->bv_len);
- *page_offset = (size_t) (bio_vec->bv_offset + cursor->vector_offset);
+ *page_offset = (size_t) bio_vec.bv_offset;
BUG_ON(*page_offset >= PAGE_SIZE);
if (cursor->last_piece) /* pagelist offset is always 0 */
*length = cursor->resid;
else
- *length = (size_t) (bio_vec->bv_len - cursor->vector_offset);
+ *length = (size_t) bio_vec.bv_len;
BUG_ON(*length > cursor->resid);
BUG_ON(*page_offset + *length > PAGE_SIZE);

- return bio_vec->bv_page;
+ return bio_vec.bv_page;
}

static bool ceph_msg_data_bio_advance(struct ceph_msg_data_cursor *cursor,
size_t bytes)
{
struct bio *bio;
- struct bio_vec *bio_vec;
- unsigned int index;
+ struct bio_vec bio_vec;

BUG_ON(cursor->data->type != CEPH_MSG_DATA_BIO);

bio = cursor->bio;
BUG_ON(!bio);

- index = cursor->vector_index;
- BUG_ON(index >= (unsigned int) bio->bi_vcnt);
- bio_vec = &bio->bi_io_vec[index];
+ bio_vec = bio_iter_iovec(bio, cursor->bvec_iter);

/* Advance the cursor offset */

BUG_ON(cursor->resid < bytes);
cursor->resid -= bytes;
- cursor->vector_offset += bytes;
- if (cursor->vector_offset < bio_vec->bv_len)
+
+ bio_advance_iter(bio, &cursor->bvec_iter, bytes);
+
+ if (bytes < bio_vec.bv_len)
return false; /* more bytes to process in this segment */
- BUG_ON(cursor->vector_offset != bio_vec->bv_len);

/* Move on to the next segment, and possibly the next bio */

- if (++index == (unsigned int) bio->bi_vcnt) {
+ if (!cursor->bvec_iter.bi_size) {
bio = bio->bi_next;
- index = 0;
+ cursor->bvec_iter = bio->bi_iter;
}
cursor->bio = bio;
- cursor->vector_index = index;
- cursor->vector_offset = 0;

if (!cursor->last_piece) {
BUG_ON(!cursor->resid);
BUG_ON(!bio);
/* A short read is OK, so use <= rather than == */
- if (cursor->resid <= bio->bi_io_vec[index].bv_len)
+ if (cursor->resid <= bio_iter_len(bio, cursor->bvec_iter))
cursor->last_piece = true;
}

--
1.8.4.rc1