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author | Ilya Dryomov <idryomov@gmail.com> | 2018-01-20 10:30:10 +0100 |
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committer | Ilya Dryomov <idryomov@gmail.com> | 2018-04-02 10:12:38 +0200 |
commit | 5359a17d2706b86da2af83027343d5eb256f7670 (patch) | |
tree | 31053fe22a0d91b40911882b2aaa961e77504d4b /net/ceph/messenger.c | |
parent | a1fbb5e7bbb56fccdf54bf4ab5086c6080ee5bfa (diff) | |
download | linux-5359a17d2706b86da2af83027343d5eb256f7670.tar.gz linux-5359a17d2706b86da2af83027343d5eb256f7670.tar.bz2 linux-5359a17d2706b86da2af83027343d5eb256f7670.zip |
libceph, rbd: new bio handling code (aka don't clone bios)
The reason we clone bios is to be able to give each object request
(and consequently each ceph_osd_data/ceph_msg_data item) its own
pointer to a (list of) bio(s). The messenger then initializes its
cursor with cloned bio's ->bi_iter, so it knows where to start reading
from/writing to. That's all the cloned bios are used for: to determine
each object request's starting position in the provided data buffer.
Introduce ceph_bio_iter to do exactly that -- store position within bio
list (i.e. pointer to bio) + position within that bio (i.e. bvec_iter).
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'net/ceph/messenger.c')
-rw-r--r-- | net/ceph/messenger.c | 101 |
1 files changed, 34 insertions, 67 deletions
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index 8a4d3758030b..b9fa8b869c08 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -839,90 +839,57 @@ static void ceph_msg_data_bio_cursor_init(struct ceph_msg_data_cursor *cursor, size_t length) { struct ceph_msg_data *data = cursor->data; - struct bio *bio; + struct ceph_bio_iter *it = &cursor->bio_iter; - BUG_ON(data->type != CEPH_MSG_DATA_BIO); + cursor->resid = min_t(size_t, length, data->bio_length); + *it = data->bio_pos; + if (cursor->resid < it->iter.bi_size) + it->iter.bi_size = cursor->resid; - bio = data->bio; - BUG_ON(!bio); - - cursor->resid = min(length, data->bio_length); - cursor->bio = bio; - cursor->bvec_iter = bio->bi_iter; - cursor->last_piece = - cursor->resid <= bio_iter_len(bio, cursor->bvec_iter); + BUG_ON(cursor->resid < bio_iter_len(it->bio, it->iter)); + cursor->last_piece = cursor->resid == bio_iter_len(it->bio, it->iter); } static struct page *ceph_msg_data_bio_next(struct ceph_msg_data_cursor *cursor, size_t *page_offset, size_t *length) { - struct ceph_msg_data *data = cursor->data; - struct bio *bio; - struct bio_vec bio_vec; - - BUG_ON(data->type != CEPH_MSG_DATA_BIO); - - bio = cursor->bio; - BUG_ON(!bio); + struct bio_vec bv = bio_iter_iovec(cursor->bio_iter.bio, + cursor->bio_iter.iter); - bio_vec = bio_iter_iovec(bio, cursor->bvec_iter); - - *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; - BUG_ON(*length > cursor->resid); - BUG_ON(*page_offset + *length > PAGE_SIZE); - - return bio_vec.bv_page; + *page_offset = bv.bv_offset; + *length = bv.bv_len; + return bv.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; - - BUG_ON(cursor->data->type != CEPH_MSG_DATA_BIO); - - bio = cursor->bio; - BUG_ON(!bio); - - bio_vec = bio_iter_iovec(bio, cursor->bvec_iter); + struct ceph_bio_iter *it = &cursor->bio_iter; - /* Advance the cursor offset */ - - BUG_ON(cursor->resid < bytes); + BUG_ON(bytes > cursor->resid); + BUG_ON(bytes > bio_iter_len(it->bio, it->iter)); cursor->resid -= bytes; + bio_advance_iter(it->bio, &it->iter, bytes); - bio_advance_iter(bio, &cursor->bvec_iter, bytes); + if (!cursor->resid) { + BUG_ON(!cursor->last_piece); + return false; /* no more data */ + } - if (bytes < bio_vec.bv_len) + if (!bytes || (it->iter.bi_size && it->iter.bi_bvec_done)) return false; /* more bytes to process in this segment */ - /* Move on to the next segment, and possibly the next bio */ - - if (!cursor->bvec_iter.bi_size) { - bio = bio->bi_next; - cursor->bio = bio; - if (bio) - cursor->bvec_iter = bio->bi_iter; - else - memset(&cursor->bvec_iter, 0, - sizeof(cursor->bvec_iter)); - } - - if (!cursor->last_piece) { - BUG_ON(!cursor->resid); - BUG_ON(!bio); - /* A short read is OK, so use <= rather than == */ - if (cursor->resid <= bio_iter_len(bio, cursor->bvec_iter)) - cursor->last_piece = true; + if (!it->iter.bi_size) { + it->bio = it->bio->bi_next; + it->iter = it->bio->bi_iter; + if (cursor->resid < it->iter.bi_size) + it->iter.bi_size = cursor->resid; } + BUG_ON(cursor->last_piece); + BUG_ON(cursor->resid < bio_iter_len(it->bio, it->iter)); + cursor->last_piece = cursor->resid == bio_iter_len(it->bio, it->iter); return true; } #endif /* CONFIG_BLOCK */ @@ -1163,9 +1130,11 @@ static struct page *ceph_msg_data_next(struct ceph_msg_data_cursor *cursor, page = NULL; break; } + BUG_ON(!page); BUG_ON(*page_offset + *length > PAGE_SIZE); BUG_ON(!*length); + BUG_ON(*length > cursor->resid); if (last_piece) *last_piece = cursor->last_piece; @@ -3262,16 +3231,14 @@ void ceph_msg_data_add_pagelist(struct ceph_msg *msg, EXPORT_SYMBOL(ceph_msg_data_add_pagelist); #ifdef CONFIG_BLOCK -void ceph_msg_data_add_bio(struct ceph_msg *msg, struct bio *bio, - size_t length) +void ceph_msg_data_add_bio(struct ceph_msg *msg, struct ceph_bio_iter *bio_pos, + u32 length) { struct ceph_msg_data *data; - BUG_ON(!bio); - data = ceph_msg_data_create(CEPH_MSG_DATA_BIO); BUG_ON(!data); - data->bio = bio; + data->bio_pos = *bio_pos; data->bio_length = length; list_add_tail(&data->links, &msg->data); |