From 5359a17d2706b86da2af83027343d5eb256f7670 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Sat, 20 Jan 2018 10:30:10 +0100 Subject: [PATCH] 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 ++++++++++++--------- include/linux/ceph/messenger.h | 59 ++++++++++++++++--- include/linux/ceph/osd_client.h | 11 ++-- net/ceph/messenger.c | 101 +++++++++++--------------------- net/ceph/osd_client.c | 13 ++-- 5 files changed, 139 insertions(+), 112 deletions(-) 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; diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h index ead9d85f1c11..d7b9605fd51d 100644 --- a/include/linux/ceph/messenger.h +++ b/include/linux/ceph/messenger.h @@ -93,14 +93,60 @@ static __inline__ bool ceph_msg_data_type_valid(enum ceph_msg_data_type type) } } +#ifdef CONFIG_BLOCK + +struct ceph_bio_iter { + struct bio *bio; + struct bvec_iter iter; +}; + +#define __ceph_bio_iter_advance_step(it, n, STEP) do { \ + unsigned int __n = (n), __cur_n; \ + \ + while (__n) { \ + BUG_ON(!(it)->iter.bi_size); \ + __cur_n = min((it)->iter.bi_size, __n); \ + (void)(STEP); \ + bio_advance_iter((it)->bio, &(it)->iter, __cur_n); \ + if (!(it)->iter.bi_size && (it)->bio->bi_next) { \ + dout("__ceph_bio_iter_advance_step next bio\n"); \ + (it)->bio = (it)->bio->bi_next; \ + (it)->iter = (it)->bio->bi_iter; \ + } \ + __n -= __cur_n; \ + } \ +} while (0) + +/* + * Advance @it by @n bytes. + */ +#define ceph_bio_iter_advance(it, n) \ + __ceph_bio_iter_advance_step(it, n, 0) + +/* + * Advance @it by @n bytes, executing BVEC_STEP for each bio_vec. + */ +#define ceph_bio_iter_advance_step(it, n, BVEC_STEP) \ + __ceph_bio_iter_advance_step(it, n, ({ \ + struct bio_vec bv; \ + struct bvec_iter __cur_iter; \ + \ + __cur_iter = (it)->iter; \ + __cur_iter.bi_size = __cur_n; \ + __bio_for_each_segment(bv, (it)->bio, __cur_iter, __cur_iter) \ + (void)(BVEC_STEP); \ + })) + +#endif /* CONFIG_BLOCK */ + struct ceph_msg_data { struct list_head links; /* ceph_msg->data */ enum ceph_msg_data_type type; union { #ifdef CONFIG_BLOCK struct { - struct bio *bio; - size_t bio_length; + struct ceph_bio_iter bio_pos; + u32 bio_length; }; #endif /* CONFIG_BLOCK */ struct { @@ -122,10 +168,7 @@ struct ceph_msg_data_cursor { bool need_crc; /* crc update needed */ union { #ifdef CONFIG_BLOCK - struct { /* bio */ - struct bio *bio; /* bio from list */ - struct bvec_iter bvec_iter; - }; + struct ceph_bio_iter bio_iter; #endif /* CONFIG_BLOCK */ struct { /* pages */ unsigned int page_offset; /* offset in page */ @@ -290,8 +333,8 @@ extern void ceph_msg_data_add_pages(struct ceph_msg *msg, struct page **pages, extern void ceph_msg_data_add_pagelist(struct ceph_msg *msg, struct ceph_pagelist *pagelist); #ifdef CONFIG_BLOCK -extern 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); #endif /* CONFIG_BLOCK */ extern struct ceph_msg *ceph_msg_new(int type, int front_len, gfp_t flags, diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h index 52fb37d1c2a5..315691490cb0 100644 --- a/include/linux/ceph/osd_client.h +++ b/include/linux/ceph/osd_client.h @@ -72,8 +72,8 @@ struct ceph_osd_data { struct ceph_pagelist *pagelist; #ifdef CONFIG_BLOCK struct { - struct bio *bio; /* list of bios */ - size_t bio_length; /* total in list */ + struct ceph_bio_iter bio_pos; + u32 bio_length; }; #endif /* CONFIG_BLOCK */ }; @@ -405,9 +405,10 @@ extern void osd_req_op_extent_osd_data_pagelist(struct ceph_osd_request *, unsigned int which, struct ceph_pagelist *pagelist); #ifdef CONFIG_BLOCK -extern void osd_req_op_extent_osd_data_bio(struct ceph_osd_request *, - unsigned int which, - struct bio *bio, size_t bio_length); +void osd_req_op_extent_osd_data_bio(struct ceph_osd_request *osd_req, + unsigned int which, + struct ceph_bio_iter *bio_pos, + u32 bio_length); #endif /* CONFIG_BLOCK */ extern void osd_req_op_cls_request_data_pagelist(struct ceph_osd_request *, 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; + struct bio_vec bv = bio_iter_iovec(cursor->bio_iter.bio, + cursor->bio_iter.iter); - BUG_ON(data->type != CEPH_MSG_DATA_BIO); - - bio = cursor->bio; - BUG_ON(!bio); - - 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; + struct ceph_bio_iter *it = &cursor->bio_iter; - BUG_ON(cursor->data->type != CEPH_MSG_DATA_BIO); - - bio = cursor->bio; - BUG_ON(!bio); - - bio_vec = bio_iter_iovec(bio, cursor->bvec_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); diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c index 4b0485458d26..339d8773ebe8 100644 --- a/net/ceph/osd_client.c +++ b/net/ceph/osd_client.c @@ -146,10 +146,11 @@ static void ceph_osd_data_pagelist_init(struct ceph_osd_data *osd_data, #ifdef CONFIG_BLOCK static void ceph_osd_data_bio_init(struct ceph_osd_data *osd_data, - struct bio *bio, size_t bio_length) + struct ceph_bio_iter *bio_pos, + u32 bio_length) { osd_data->type = CEPH_OSD_DATA_TYPE_BIO; - osd_data->bio = bio; + osd_data->bio_pos = *bio_pos; osd_data->bio_length = bio_length; } #endif /* CONFIG_BLOCK */ @@ -216,12 +217,14 @@ EXPORT_SYMBOL(osd_req_op_extent_osd_data_pagelist); #ifdef CONFIG_BLOCK void osd_req_op_extent_osd_data_bio(struct ceph_osd_request *osd_req, - unsigned int which, struct bio *bio, size_t bio_length) + unsigned int which, + struct ceph_bio_iter *bio_pos, + u32 bio_length) { struct ceph_osd_data *osd_data; osd_data = osd_req_op_data(osd_req, which, extent, osd_data); - ceph_osd_data_bio_init(osd_data, bio, bio_length); + ceph_osd_data_bio_init(osd_data, bio_pos, bio_length); } EXPORT_SYMBOL(osd_req_op_extent_osd_data_bio); #endif /* CONFIG_BLOCK */ @@ -826,7 +829,7 @@ static void ceph_osdc_msg_data_add(struct ceph_msg *msg, ceph_msg_data_add_pagelist(msg, osd_data->pagelist); #ifdef CONFIG_BLOCK } else if (osd_data->type == CEPH_OSD_DATA_TYPE_BIO) { - ceph_msg_data_add_bio(msg, osd_data->bio, length); + ceph_msg_data_add_bio(msg, &osd_data->bio_pos, length); #endif } else { BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_NONE);