From b9e281c2b38804984d619e1d9efc4b9020bcb291 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Sat, 20 Jan 2018 10:30:11 +0100 Subject: libceph: introduce BVECS data type In preparation for rbd "fancy" striping, introduce ceph_bvec_iter for working with bio_vec array data buffers. The wrappers are trivial, but make it look similar to ceph_bio_iter. Signed-off-by: Ilya Dryomov --- net/ceph/messenger.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) (limited to 'net/ceph/messenger.c') diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index b9fa8b869c08..91a57857cf11 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -894,6 +894,58 @@ static bool ceph_msg_data_bio_advance(struct ceph_msg_data_cursor *cursor, } #endif /* CONFIG_BLOCK */ +static void ceph_msg_data_bvecs_cursor_init(struct ceph_msg_data_cursor *cursor, + size_t length) +{ + struct ceph_msg_data *data = cursor->data; + struct bio_vec *bvecs = data->bvec_pos.bvecs; + + cursor->resid = min_t(size_t, length, data->bvec_pos.iter.bi_size); + cursor->bvec_iter = data->bvec_pos.iter; + cursor->bvec_iter.bi_size = cursor->resid; + + BUG_ON(cursor->resid < bvec_iter_len(bvecs, cursor->bvec_iter)); + cursor->last_piece = + cursor->resid == bvec_iter_len(bvecs, cursor->bvec_iter); +} + +static struct page *ceph_msg_data_bvecs_next(struct ceph_msg_data_cursor *cursor, + size_t *page_offset, + size_t *length) +{ + struct bio_vec bv = bvec_iter_bvec(cursor->data->bvec_pos.bvecs, + cursor->bvec_iter); + + *page_offset = bv.bv_offset; + *length = bv.bv_len; + return bv.bv_page; +} + +static bool ceph_msg_data_bvecs_advance(struct ceph_msg_data_cursor *cursor, + size_t bytes) +{ + struct bio_vec *bvecs = cursor->data->bvec_pos.bvecs; + + BUG_ON(bytes > cursor->resid); + BUG_ON(bytes > bvec_iter_len(bvecs, cursor->bvec_iter)); + cursor->resid -= bytes; + bvec_iter_advance(bvecs, &cursor->bvec_iter, bytes); + + if (!cursor->resid) { + BUG_ON(!cursor->last_piece); + return false; /* no more data */ + } + + if (!bytes || cursor->bvec_iter.bi_bvec_done) + return false; /* more bytes to process in this segment */ + + BUG_ON(cursor->last_piece); + BUG_ON(cursor->resid < bvec_iter_len(bvecs, cursor->bvec_iter)); + cursor->last_piece = + cursor->resid == bvec_iter_len(bvecs, cursor->bvec_iter); + return true; +} + /* * For a page array, a piece comes from the first page in the array * that has not already been fully consumed. @@ -1077,6 +1129,9 @@ static void __ceph_msg_data_cursor_init(struct ceph_msg_data_cursor *cursor) ceph_msg_data_bio_cursor_init(cursor, length); break; #endif /* CONFIG_BLOCK */ + case CEPH_MSG_DATA_BVECS: + ceph_msg_data_bvecs_cursor_init(cursor, length); + break; case CEPH_MSG_DATA_NONE: default: /* BUG(); */ @@ -1125,6 +1180,9 @@ static struct page *ceph_msg_data_next(struct ceph_msg_data_cursor *cursor, page = ceph_msg_data_bio_next(cursor, page_offset, length); break; #endif /* CONFIG_BLOCK */ + case CEPH_MSG_DATA_BVECS: + page = ceph_msg_data_bvecs_next(cursor, page_offset, length); + break; case CEPH_MSG_DATA_NONE: default: page = NULL; @@ -1163,6 +1221,9 @@ static void ceph_msg_data_advance(struct ceph_msg_data_cursor *cursor, new_piece = ceph_msg_data_bio_advance(cursor, bytes); break; #endif /* CONFIG_BLOCK */ + case CEPH_MSG_DATA_BVECS: + new_piece = ceph_msg_data_bvecs_advance(cursor, bytes); + break; case CEPH_MSG_DATA_NONE: default: BUG(); @@ -3247,6 +3308,20 @@ void ceph_msg_data_add_bio(struct ceph_msg *msg, struct ceph_bio_iter *bio_pos, EXPORT_SYMBOL(ceph_msg_data_add_bio); #endif /* CONFIG_BLOCK */ +void ceph_msg_data_add_bvecs(struct ceph_msg *msg, + struct ceph_bvec_iter *bvec_pos) +{ + struct ceph_msg_data *data; + + data = ceph_msg_data_create(CEPH_MSG_DATA_BVECS); + BUG_ON(!data); + data->bvec_pos = *bvec_pos; + + list_add_tail(&data->links, &msg->data); + msg->data_length += bvec_pos->iter.bi_size; +} +EXPORT_SYMBOL(ceph_msg_data_add_bvecs); + /* * construct a new message with given type, size * the new msg has a ref count of 1. -- cgit v1.2.1