From 5359a17d2706b86da2af83027343d5eb256f7670 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Sat, 20 Jan 2018 10:30:10 +0100 Subject: 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 --- drivers/block/rbd.c | 67 ++++++++++++++++++++++++++++++++--------------------- 1 file changed, 40 insertions(+), 27 deletions(-) (limited to 'drivers') diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 883f17d6deeb..8eaebf609611 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -218,7 +218,7 @@ typedef void (*rbd_obj_callback_t)(struct rbd_obj_request *); enum obj_request_type { OBJ_REQUEST_NODATA = 1, - OBJ_REQUEST_BIO, + OBJ_REQUEST_BIO, /* pointer into provided bio (list) */ OBJ_REQUEST_PAGES, }; @@ -270,7 +270,7 @@ struct rbd_obj_request { enum obj_request_type type; union { - struct bio *bio_list; + struct ceph_bio_iter bio_pos; struct { struct page **pages; u32 page_count; @@ -1255,6 +1255,27 @@ static u64 rbd_segment_length(struct rbd_device *rbd_dev, return length; } +static void zero_bvec(struct bio_vec *bv) +{ + void *buf; + unsigned long flags; + + buf = bvec_kmap_irq(bv, &flags); + memset(buf, 0, bv->bv_len); + flush_dcache_page(bv->bv_page); + bvec_kunmap_irq(buf, &flags); +} + +static void zero_bios(struct ceph_bio_iter *bio_pos, u32 off, u32 bytes) +{ + struct ceph_bio_iter it = *bio_pos; + + ceph_bio_iter_advance(&it, off); + ceph_bio_iter_advance_step(&it, bytes, ({ + zero_bvec(&bv); + })); +} + /* * bio helpers */ @@ -1719,13 +1740,14 @@ rbd_img_obj_request_read_callback(struct rbd_obj_request *obj_request) rbd_assert(obj_request->type != OBJ_REQUEST_NODATA); if (obj_request->result == -ENOENT) { if (obj_request->type == OBJ_REQUEST_BIO) - zero_bio_chain(obj_request->bio_list, 0); + zero_bios(&obj_request->bio_pos, 0, length); else zero_pages(obj_request->pages, 0, length); obj_request->result = 0; } else if (xferred < length && !obj_request->result) { if (obj_request->type == OBJ_REQUEST_BIO) - zero_bio_chain(obj_request->bio_list, xferred); + zero_bios(&obj_request->bio_pos, xferred, + length - xferred); else zero_pages(obj_request->pages, xferred, length); } @@ -2036,11 +2058,8 @@ static void rbd_obj_request_destroy(struct kref *kref) rbd_assert(obj_request_type_valid(obj_request->type)); switch (obj_request->type) { case OBJ_REQUEST_NODATA: - break; /* Nothing to do */ case OBJ_REQUEST_BIO: - if (obj_request->bio_list) - bio_chain_put(obj_request->bio_list); - break; + break; /* Nothing to do */ case OBJ_REQUEST_PAGES: /* img_data requests don't own their page array */ if (obj_request->pages && @@ -2368,7 +2387,7 @@ static void rbd_img_obj_request_fill(struct rbd_obj_request *obj_request, if (obj_request->type == OBJ_REQUEST_BIO) osd_req_op_extent_osd_data_bio(osd_request, num_ops, - obj_request->bio_list, length); + &obj_request->bio_pos, length); else if (obj_request->type == OBJ_REQUEST_PAGES) osd_req_op_extent_osd_data_pages(osd_request, num_ops, obj_request->pages, length, @@ -2396,8 +2415,7 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request, struct rbd_device *rbd_dev = img_request->rbd_dev; struct rbd_obj_request *obj_request = NULL; struct rbd_obj_request *next_obj_request; - struct bio *bio_list = NULL; - unsigned int bio_offset = 0; + struct ceph_bio_iter bio_it; struct page **pages = NULL; enum obj_operation_type op_type; u64 img_offset; @@ -2412,9 +2430,9 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request, op_type = rbd_img_request_op_type(img_request); if (type == OBJ_REQUEST_BIO) { - bio_list = data_desc; + bio_it = *(struct ceph_bio_iter *)data_desc; rbd_assert(img_offset == - bio_list->bi_iter.bi_sector << SECTOR_SHIFT); + bio_it.iter.bi_sector << SECTOR_SHIFT); } else if (type == OBJ_REQUEST_PAGES) { pages = data_desc; } @@ -2440,17 +2458,8 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request, rbd_img_obj_request_add(img_request, obj_request); if (type == OBJ_REQUEST_BIO) { - unsigned int clone_size; - - rbd_assert(length <= (u64)UINT_MAX); - clone_size = (unsigned int)length; - obj_request->bio_list = - bio_chain_clone_range(&bio_list, - &bio_offset, - clone_size, - GFP_NOIO); - if (!obj_request->bio_list) - goto out_unwind; + obj_request->bio_pos = bio_it; + ceph_bio_iter_advance(&bio_it, length); } else if (type == OBJ_REQUEST_PAGES) { unsigned int page_count; @@ -2980,7 +2989,7 @@ static void rbd_img_parent_read(struct rbd_obj_request *obj_request) if (obj_request->type == OBJ_REQUEST_BIO) result = rbd_img_request_fill(img_request, OBJ_REQUEST_BIO, - obj_request->bio_list); + &obj_request->bio_pos); else result = rbd_img_request_fill(img_request, OBJ_REQUEST_PAGES, obj_request->pages); @@ -4093,9 +4102,13 @@ static void rbd_queue_workfn(struct work_struct *work) if (op_type == OBJ_OP_DISCARD) result = rbd_img_request_fill(img_request, OBJ_REQUEST_NODATA, NULL); - else + else { + struct ceph_bio_iter bio_it = { .bio = rq->bio, + .iter = rq->bio->bi_iter }; + result = rbd_img_request_fill(img_request, OBJ_REQUEST_BIO, - rq->bio); + &bio_it); + } if (result) goto err_img_request; -- cgit v1.2.3