diff options
Diffstat (limited to 'drivers/lightnvm/pblk-rb.c')
| -rw-r--r-- | drivers/lightnvm/pblk-rb.c | 858 |
1 files changed, 858 insertions, 0 deletions
diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c new file mode 100644 index 000000000..5abb1705b --- /dev/null +++ b/drivers/lightnvm/pblk-rb.c @@ -0,0 +1,858 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2016 CNEX Labs + * Initial release: Javier Gonzalez <javier@cnexlabs.com> + * + * Based upon the circular ringbuffer. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version + * 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * pblk-rb.c - pblk's write buffer + */ + +#include <linux/circ_buf.h> + +#include "pblk.h" + +static DECLARE_RWSEM(pblk_rb_lock); + +static void pblk_rb_data_free(struct pblk_rb *rb) +{ + struct pblk_rb_pages *p, *t; + + down_write(&pblk_rb_lock); + list_for_each_entry_safe(p, t, &rb->pages, list) { + free_pages((unsigned long)page_address(p->pages), p->order); + list_del(&p->list); + kfree(p); + } + up_write(&pblk_rb_lock); +} + +void pblk_rb_free(struct pblk_rb *rb) +{ + pblk_rb_data_free(rb); + vfree(rb->entries); +} + +/* + * pblk_rb_calculate_size -- calculate the size of the write buffer + */ +static unsigned int pblk_rb_calculate_size(unsigned int nr_entries, + unsigned int threshold) +{ + unsigned int thr_sz = 1 << (get_count_order(threshold + NVM_MAX_VLBA)); + unsigned int max_sz = max(thr_sz, nr_entries); + unsigned int max_io; + + /* Alloc a write buffer that can (i) fit at least two split bios + * (considering max I/O size NVM_MAX_VLBA, and (ii) guarantee that the + * threshold will be respected + */ + max_io = (1 << max((int)(get_count_order(max_sz)), + (int)(get_count_order(NVM_MAX_VLBA << 1)))); + if ((threshold + NVM_MAX_VLBA) >= max_io) + max_io <<= 1; + + return max_io; +} + +/* + * Initialize ring buffer. The data and metadata buffers must be previously + * allocated and their size must be a power of two + * (Documentation/core-api/circular-buffers.rst) + */ +int pblk_rb_init(struct pblk_rb *rb, unsigned int size, unsigned int threshold, + unsigned int seg_size) +{ + struct pblk *pblk = container_of(rb, struct pblk, rwb); + struct pblk_rb_entry *entries; + unsigned int init_entry = 0; + unsigned int max_order = MAX_ORDER - 1; + unsigned int power_size, power_seg_sz; + unsigned int alloc_order, order, iter; + unsigned int nr_entries; + + nr_entries = pblk_rb_calculate_size(size, threshold); + entries = vzalloc(array_size(nr_entries, sizeof(struct pblk_rb_entry))); + if (!entries) + return -ENOMEM; + + power_size = get_count_order(nr_entries); + power_seg_sz = get_count_order(seg_size); + + down_write(&pblk_rb_lock); + rb->entries = entries; + rb->seg_size = (1 << power_seg_sz); + rb->nr_entries = (1 << power_size); + rb->mem = rb->subm = rb->sync = rb->l2p_update = 0; + rb->back_thres = threshold; + rb->flush_point = EMPTY_ENTRY; + + spin_lock_init(&rb->w_lock); + spin_lock_init(&rb->s_lock); + + INIT_LIST_HEAD(&rb->pages); + + alloc_order = power_size; + if (alloc_order >= max_order) { + order = max_order; + iter = (1 << (alloc_order - max_order)); + } else { + order = alloc_order; + iter = 1; + } + + do { + struct pblk_rb_entry *entry; + struct pblk_rb_pages *page_set; + void *kaddr; + unsigned long set_size; + int i; + + page_set = kmalloc(sizeof(struct pblk_rb_pages), GFP_KERNEL); + if (!page_set) { + up_write(&pblk_rb_lock); + vfree(entries); + return -ENOMEM; + } + + page_set->order = order; + page_set->pages = alloc_pages(GFP_KERNEL, order); + if (!page_set->pages) { + kfree(page_set); + pblk_rb_data_free(rb); + up_write(&pblk_rb_lock); + vfree(entries); + return -ENOMEM; + } + kaddr = page_address(page_set->pages); + + entry = &rb->entries[init_entry]; + entry->data = kaddr; + entry->cacheline = pblk_cacheline_to_addr(init_entry++); + entry->w_ctx.flags = PBLK_WRITABLE_ENTRY; + + set_size = (1 << order); + for (i = 1; i < set_size; i++) { + entry = &rb->entries[init_entry]; + entry->cacheline = pblk_cacheline_to_addr(init_entry++); + entry->data = kaddr + (i * rb->seg_size); + entry->w_ctx.flags = PBLK_WRITABLE_ENTRY; + bio_list_init(&entry->w_ctx.bios); + } + + list_add_tail(&page_set->list, &rb->pages); + iter--; + } while (iter > 0); + up_write(&pblk_rb_lock); + +#ifdef CONFIG_NVM_PBLK_DEBUG + atomic_set(&rb->inflight_flush_point, 0); +#endif + + /* + * Initialize rate-limiter, which controls access to the write buffer + * by user and GC I/O + */ + pblk_rl_init(&pblk->rl, rb->nr_entries, threshold); + + return 0; +} + +static void clean_wctx(struct pblk_w_ctx *w_ctx) +{ + int flags; + + flags = READ_ONCE(w_ctx->flags); + WARN_ONCE(!(flags & PBLK_SUBMITTED_ENTRY), + "pblk: overwriting unsubmitted data\n"); + + /* Release flags on context. Protect from writes and reads */ + smp_store_release(&w_ctx->flags, PBLK_WRITABLE_ENTRY); + pblk_ppa_set_empty(&w_ctx->ppa); + w_ctx->lba = ADDR_EMPTY; +} + +#define pblk_rb_ring_count(head, tail, size) CIRC_CNT(head, tail, size) +#define pblk_rb_ring_space(rb, head, tail, size) \ + (CIRC_SPACE(head, tail, size)) + +/* + * Buffer space is calculated with respect to the back pointer signaling + * synchronized entries to the media. + */ +static unsigned int pblk_rb_space(struct pblk_rb *rb) +{ + unsigned int mem = READ_ONCE(rb->mem); + unsigned int sync = READ_ONCE(rb->sync); + + return pblk_rb_ring_space(rb, mem, sync, rb->nr_entries); +} + +unsigned int pblk_rb_ptr_wrap(struct pblk_rb *rb, unsigned int p, + unsigned int nr_entries) +{ + return (p + nr_entries) & (rb->nr_entries - 1); +} + +/* + * Buffer count is calculated with respect to the submission entry signaling the + * entries that are available to send to the media + */ +unsigned int pblk_rb_read_count(struct pblk_rb *rb) +{ + unsigned int mem = READ_ONCE(rb->mem); + unsigned int subm = READ_ONCE(rb->subm); + + return pblk_rb_ring_count(mem, subm, rb->nr_entries); +} + +unsigned int pblk_rb_sync_count(struct pblk_rb *rb) +{ + unsigned int mem = READ_ONCE(rb->mem); + unsigned int sync = READ_ONCE(rb->sync); + + return pblk_rb_ring_count(mem, sync, rb->nr_entries); +} + +unsigned int pblk_rb_read_commit(struct pblk_rb *rb, unsigned int nr_entries) +{ + unsigned int subm; + + subm = READ_ONCE(rb->subm); + /* Commit read means updating submission pointer */ + smp_store_release(&rb->subm, pblk_rb_ptr_wrap(rb, subm, nr_entries)); + + return subm; +} + +static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int to_update) +{ + struct pblk *pblk = container_of(rb, struct pblk, rwb); + struct pblk_line *line; + struct pblk_rb_entry *entry; + struct pblk_w_ctx *w_ctx; + unsigned int user_io = 0, gc_io = 0; + unsigned int i; + int flags; + + for (i = 0; i < to_update; i++) { + entry = &rb->entries[rb->l2p_update]; + w_ctx = &entry->w_ctx; + + flags = READ_ONCE(entry->w_ctx.flags); + if (flags & PBLK_IOTYPE_USER) + user_io++; + else if (flags & PBLK_IOTYPE_GC) + gc_io++; + else + WARN(1, "pblk: unknown IO type\n"); + + pblk_update_map_dev(pblk, w_ctx->lba, w_ctx->ppa, + entry->cacheline); + + line = pblk_ppa_to_line(pblk, w_ctx->ppa); + atomic_dec(&line->sec_to_update); + kref_put(&line->ref, pblk_line_put); + clean_wctx(w_ctx); + rb->l2p_update = pblk_rb_ptr_wrap(rb, rb->l2p_update, 1); + } + + pblk_rl_out(&pblk->rl, user_io, gc_io); + + return 0; +} + +/* + * When we move the l2p_update pointer, we update the l2p table - lookups will + * point to the physical address instead of to the cacheline in the write buffer + * from this moment on. + */ +static int pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int nr_entries, + unsigned int mem, unsigned int sync) +{ + unsigned int space, count; + int ret = 0; + + lockdep_assert_held(&rb->w_lock); + + /* Update l2p only as buffer entries are being overwritten */ + space = pblk_rb_ring_space(rb, mem, rb->l2p_update, rb->nr_entries); + if (space > nr_entries) + goto out; + + count = nr_entries - space; + /* l2p_update used exclusively under rb->w_lock */ + ret = __pblk_rb_update_l2p(rb, count); + +out: + return ret; +} + +/* + * Update the l2p entry for all sectors stored on the write buffer. This means + * that all future lookups to the l2p table will point to a device address, not + * to the cacheline in the write buffer. + */ +void pblk_rb_sync_l2p(struct pblk_rb *rb) +{ + unsigned int sync; + unsigned int to_update; + + spin_lock(&rb->w_lock); + + /* Protect from reads and writes */ + sync = smp_load_acquire(&rb->sync); + + to_update = pblk_rb_ring_count(sync, rb->l2p_update, rb->nr_entries); + __pblk_rb_update_l2p(rb, to_update); + + spin_unlock(&rb->w_lock); +} + +/* + * Write @nr_entries to ring buffer from @data buffer if there is enough space. + * Typically, 4KB data chunks coming from a bio will be copied to the ring + * buffer, thus the write will fail if not all incoming data can be copied. + * + */ +static void __pblk_rb_write_entry(struct pblk_rb *rb, void *data, + struct pblk_w_ctx w_ctx, + struct pblk_rb_entry *entry) +{ + memcpy(entry->data, data, rb->seg_size); + + entry->w_ctx.lba = w_ctx.lba; + entry->w_ctx.ppa = w_ctx.ppa; +} + +void pblk_rb_write_entry_user(struct pblk_rb *rb, void *data, + struct pblk_w_ctx w_ctx, unsigned int ring_pos) +{ + struct pblk *pblk = container_of(rb, struct pblk, rwb); + struct pblk_rb_entry *entry; + int flags; + + entry = &rb->entries[ring_pos]; + flags = READ_ONCE(entry->w_ctx.flags); +#ifdef CONFIG_NVM_PBLK_DEBUG + /* Caller must guarantee that the entry is free */ + BUG_ON(!(flags & PBLK_WRITABLE_ENTRY)); +#endif + + __pblk_rb_write_entry(rb, data, w_ctx, entry); + + pblk_update_map_cache(pblk, w_ctx.lba, entry->cacheline); + flags = w_ctx.flags | PBLK_WRITTEN_DATA; + + /* Release flags on write context. Protect from writes */ + smp_store_release(&entry->w_ctx.flags, flags); +} + +void pblk_rb_write_entry_gc(struct pblk_rb *rb, void *data, + struct pblk_w_ctx w_ctx, struct pblk_line *line, + u64 paddr, unsigned int ring_pos) +{ + struct pblk *pblk = container_of(rb, struct pblk, rwb); + struct pblk_rb_entry *entry; + int flags; + + entry = &rb->entries[ring_pos]; + flags = READ_ONCE(entry->w_ctx.flags); +#ifdef CONFIG_NVM_PBLK_DEBUG + /* Caller must guarantee that the entry is free */ + BUG_ON(!(flags & PBLK_WRITABLE_ENTRY)); +#endif + + __pblk_rb_write_entry(rb, data, w_ctx, entry); + + if (!pblk_update_map_gc(pblk, w_ctx.lba, entry->cacheline, line, paddr)) + entry->w_ctx.lba = ADDR_EMPTY; + + flags = w_ctx.flags | PBLK_WRITTEN_DATA; + + /* Release flags on write context. Protect from writes */ + smp_store_release(&entry->w_ctx.flags, flags); +} + +static int pblk_rb_flush_point_set(struct pblk_rb *rb, struct bio *bio, + unsigned int pos) +{ + struct pblk_rb_entry *entry; + unsigned int sync, flush_point; + + pblk_rb_sync_init(rb, NULL); + sync = READ_ONCE(rb->sync); + + if (pos == sync) { + pblk_rb_sync_end(rb, NULL); + return 0; + } + +#ifdef CONFIG_NVM_PBLK_DEBUG + atomic_inc(&rb->inflight_flush_point); +#endif + + flush_point = (pos == 0) ? (rb->nr_entries - 1) : (pos - 1); + entry = &rb->entries[flush_point]; + + /* Protect flush points */ + smp_store_release(&rb->flush_point, flush_point); + + if (bio) + bio_list_add(&entry->w_ctx.bios, bio); + + pblk_rb_sync_end(rb, NULL); + + return bio ? 1 : 0; +} + +static int __pblk_rb_may_write(struct pblk_rb *rb, unsigned int nr_entries, + unsigned int *pos) +{ + unsigned int mem; + unsigned int sync; + unsigned int threshold; + + sync = READ_ONCE(rb->sync); + mem = READ_ONCE(rb->mem); + + threshold = nr_entries + rb->back_thres; + + if (pblk_rb_ring_space(rb, mem, sync, rb->nr_entries) < threshold) + return 0; + + if (pblk_rb_update_l2p(rb, nr_entries, mem, sync)) + return 0; + + *pos = mem; + + return 1; +} + +static int pblk_rb_may_write(struct pblk_rb *rb, unsigned int nr_entries, + unsigned int *pos) +{ + if (!__pblk_rb_may_write(rb, nr_entries, pos)) + return 0; + + /* Protect from read count */ + smp_store_release(&rb->mem, pblk_rb_ptr_wrap(rb, *pos, nr_entries)); + return 1; +} + +void pblk_rb_flush(struct pblk_rb *rb) +{ + struct pblk *pblk = container_of(rb, struct pblk, rwb); + unsigned int mem = READ_ONCE(rb->mem); + + if (pblk_rb_flush_point_set(rb, NULL, mem)) + return; + + pblk_write_kick(pblk); +} + +static int pblk_rb_may_write_flush(struct pblk_rb *rb, unsigned int nr_entries, + unsigned int *pos, struct bio *bio, + int *io_ret) +{ + unsigned int mem; + + if (!__pblk_rb_may_write(rb, nr_entries, pos)) + return 0; + + mem = pblk_rb_ptr_wrap(rb, *pos, nr_entries); + *io_ret = NVM_IO_DONE; + + if (bio->bi_opf & REQ_PREFLUSH) { + struct pblk *pblk = container_of(rb, struct pblk, rwb); + + atomic64_inc(&pblk->nr_flush); + if (pblk_rb_flush_point_set(&pblk->rwb, bio, mem)) + *io_ret = NVM_IO_OK; + } + + /* Protect from read count */ + smp_store_release(&rb->mem, mem); + + return 1; +} + +/* + * Atomically check that (i) there is space on the write buffer for the + * incoming I/O, and (ii) the current I/O type has enough budget in the write + * buffer (rate-limiter). + */ +int pblk_rb_may_write_user(struct pblk_rb *rb, struct bio *bio, + unsigned int nr_entries, unsigned int *pos) +{ + struct pblk *pblk = container_of(rb, struct pblk, rwb); + int io_ret; + + spin_lock(&rb->w_lock); + io_ret = pblk_rl_user_may_insert(&pblk->rl, nr_entries); + if (io_ret) { + spin_unlock(&rb->w_lock); + return io_ret; + } + + if (!pblk_rb_may_write_flush(rb, nr_entries, pos, bio, &io_ret)) { + spin_unlock(&rb->w_lock); + return NVM_IO_REQUEUE; + } + + pblk_rl_user_in(&pblk->rl, nr_entries); + spin_unlock(&rb->w_lock); + + return io_ret; +} + +/* + * Look at pblk_rb_may_write_user comment + */ +int pblk_rb_may_write_gc(struct pblk_rb *rb, unsigned int nr_entries, + unsigned int *pos) +{ + struct pblk *pblk = container_of(rb, struct pblk, rwb); + + spin_lock(&rb->w_lock); + if (!pblk_rl_gc_may_insert(&pblk->rl, nr_entries)) { + spin_unlock(&rb->w_lock); + return 0; + } + + if (!pblk_rb_may_write(rb, nr_entries, pos)) { + spin_unlock(&rb->w_lock); + return 0; + } + + pblk_rl_gc_in(&pblk->rl, nr_entries); + spin_unlock(&rb->w_lock); + + return 1; +} + +/* + * Read available entries on rb and add them to the given bio. To avoid a memory + * copy, a page reference to the write buffer is used to be added to the bio. + * + * This function is used by the write thread to form the write bio that will + * persist data on the write buffer to the media. + */ +unsigned int pblk_rb_read_to_bio(struct pblk_rb *rb, struct nvm_rq *rqd, + unsigned int pos, unsigned int nr_entries, + unsigned int count) +{ + struct pblk *pblk = container_of(rb, struct pblk, rwb); + struct request_queue *q = pblk->dev->q; + struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd); + struct bio *bio = rqd->bio; + struct pblk_rb_entry *entry; + struct page *page; + unsigned int pad = 0, to_read = nr_entries; + unsigned int i; + int flags; + + if (count < nr_entries) { + pad = nr_entries - count; + to_read = count; + } + + /* Add space for packed metadata if in use*/ + pad += (pblk->min_write_pgs - pblk->min_write_pgs_data); + + c_ctx->sentry = pos; + c_ctx->nr_valid = to_read; + c_ctx->nr_padded = pad; + + for (i = 0; i < to_read; i++) { + entry = &rb->entries[pos]; + + /* A write has been allowed into the buffer, but data is still + * being copied to it. It is ok to busy wait. + */ +try: + flags = READ_ONCE(entry->w_ctx.flags); + if (!(flags & PBLK_WRITTEN_DATA)) { + io_schedule(); + goto try; + } + + page = virt_to_page(entry->data); + if (!page) { + pblk_err(pblk, "could not allocate write bio page\n"); + flags &= ~PBLK_WRITTEN_DATA; + flags |= PBLK_SUBMITTED_ENTRY; + /* Release flags on context. Protect from writes */ + smp_store_release(&entry->w_ctx.flags, flags); + return NVM_IO_ERR; + } + + if (bio_add_pc_page(q, bio, page, rb->seg_size, 0) != + rb->seg_size) { + pblk_err(pblk, "could not add page to write bio\n"); + flags &= ~PBLK_WRITTEN_DATA; + flags |= PBLK_SUBMITTED_ENTRY; + /* Release flags on context. Protect from writes */ + smp_store_release(&entry->w_ctx.flags, flags); + return NVM_IO_ERR; + } + + flags &= ~PBLK_WRITTEN_DATA; + flags |= PBLK_SUBMITTED_ENTRY; + + /* Release flags on context. Protect from writes */ + smp_store_release(&entry->w_ctx.flags, flags); + + pos = pblk_rb_ptr_wrap(rb, pos, 1); + } + + if (pad) { + if (pblk_bio_add_pages(pblk, bio, GFP_KERNEL, pad)) { + pblk_err(pblk, "could not pad page in write bio\n"); + return NVM_IO_ERR; + } + + if (pad < pblk->min_write_pgs) + atomic64_inc(&pblk->pad_dist[pad - 1]); + else + pblk_warn(pblk, "padding more than min. sectors\n"); + + atomic64_add(pad, &pblk->pad_wa); + } + +#ifdef CONFIG_NVM_PBLK_DEBUG + atomic_long_add(pad, &pblk->padded_writes); +#endif + + return NVM_IO_OK; +} + +/* + * Copy to bio only if the lba matches the one on the given cache entry. + * Otherwise, it means that the entry has been overwritten, and the bio should + * be directed to disk. + */ +int pblk_rb_copy_to_bio(struct pblk_rb *rb, struct bio *bio, sector_t lba, + struct ppa_addr ppa) +{ + struct pblk *pblk = container_of(rb, struct pblk, rwb); + struct pblk_rb_entry *entry; + struct pblk_w_ctx *w_ctx; + struct ppa_addr l2p_ppa; + u64 pos = pblk_addr_to_cacheline(ppa); + void *data; + int flags; + int ret = 1; + + +#ifdef CONFIG_NVM_PBLK_DEBUG + /* Caller must ensure that the access will not cause an overflow */ + BUG_ON(pos >= rb->nr_entries); +#endif + entry = &rb->entries[pos]; + w_ctx = &entry->w_ctx; + flags = READ_ONCE(w_ctx->flags); + + spin_lock(&rb->w_lock); + spin_lock(&pblk->trans_lock); + l2p_ppa = pblk_trans_map_get(pblk, lba); + spin_unlock(&pblk->trans_lock); + + /* Check if the entry has been overwritten or is scheduled to be */ + if (!pblk_ppa_comp(l2p_ppa, ppa) || w_ctx->lba != lba || + flags & PBLK_WRITABLE_ENTRY) { + ret = 0; + goto out; + } + data = bio_data(bio); + memcpy(data, entry->data, rb->seg_size); + +out: + spin_unlock(&rb->w_lock); + return ret; +} + +struct pblk_w_ctx *pblk_rb_w_ctx(struct pblk_rb *rb, unsigned int pos) +{ + unsigned int entry = pblk_rb_ptr_wrap(rb, pos, 0); + + return &rb->entries[entry].w_ctx; +} + +unsigned int pblk_rb_sync_init(struct pblk_rb *rb, unsigned long *flags) + __acquires(&rb->s_lock) +{ + if (flags) + spin_lock_irqsave(&rb->s_lock, *flags); + else + spin_lock_irq(&rb->s_lock); + + return rb->sync; +} + +void pblk_rb_sync_end(struct pblk_rb *rb, unsigned long *flags) + __releases(&rb->s_lock) +{ + lockdep_assert_held(&rb->s_lock); + + if (flags) + spin_unlock_irqrestore(&rb->s_lock, *flags); + else + spin_unlock_irq(&rb->s_lock); +} + +unsigned int pblk_rb_sync_advance(struct pblk_rb *rb, unsigned int nr_entries) +{ + unsigned int sync, flush_point; + lockdep_assert_held(&rb->s_lock); + + sync = READ_ONCE(rb->sync); + flush_point = READ_ONCE(rb->flush_point); + + if (flush_point != EMPTY_ENTRY) { + unsigned int secs_to_flush; + + secs_to_flush = pblk_rb_ring_count(flush_point, sync, + rb->nr_entries); + if (secs_to_flush < nr_entries) { + /* Protect flush points */ + smp_store_release(&rb->flush_point, EMPTY_ENTRY); + } + } + + sync = pblk_rb_ptr_wrap(rb, sync, nr_entries); + + /* Protect from counts */ + smp_store_release(&rb->sync, sync); + + return sync; +} + +/* Calculate how many sectors to submit up to the current flush point. */ +unsigned int pblk_rb_flush_point_count(struct pblk_rb *rb) +{ + unsigned int subm, sync, flush_point; + unsigned int submitted, to_flush; + + /* Protect flush points */ + flush_point = smp_load_acquire(&rb->flush_point); + if (flush_point == EMPTY_ENTRY) + return 0; + + /* Protect syncs */ + sync = smp_load_acquire(&rb->sync); + + subm = READ_ONCE(rb->subm); + submitted = pblk_rb_ring_count(subm, sync, rb->nr_entries); + + /* The sync point itself counts as a sector to sync */ + to_flush = pblk_rb_ring_count(flush_point, sync, rb->nr_entries) + 1; + + return (submitted < to_flush) ? (to_flush - submitted) : 0; +} + +int pblk_rb_tear_down_check(struct pblk_rb *rb) +{ + struct pblk_rb_entry *entry; + int i; + int ret = 0; + + spin_lock(&rb->w_lock); + spin_lock_irq(&rb->s_lock); + + if ((rb->mem == rb->subm) && (rb->subm == rb->sync) && + (rb->sync == rb->l2p_update) && + (rb->flush_point == EMPTY_ENTRY)) { + goto out; + } + + if (!rb->entries) { + ret = 1; + goto out; + } + + for (i = 0; i < rb->nr_entries; i++) { + entry = &rb->entries[i]; + + if (!entry->data) { + ret = 1; + goto out; + } + } + +out: + spin_unlock_irq(&rb->s_lock); + spin_unlock(&rb->w_lock); + + return ret; +} + +unsigned int pblk_rb_wrap_pos(struct pblk_rb *rb, unsigned int pos) +{ + return (pos & (rb->nr_entries - 1)); +} + +int pblk_rb_pos_oob(struct pblk_rb *rb, u64 pos) +{ + return (pos >= rb->nr_entries); +} + +ssize_t pblk_rb_sysfs(struct pblk_rb *rb, char *buf) +{ + struct pblk *pblk = container_of(rb, struct pblk, rwb); + struct pblk_c_ctx *c; + ssize_t offset; + int queued_entries = 0; + + spin_lock_irq(&rb->s_lock); + list_for_each_entry(c, &pblk->compl_list, list) + queued_entries++; + spin_unlock_irq(&rb->s_lock); + + if (rb->flush_point != EMPTY_ENTRY) + offset = scnprintf(buf, PAGE_SIZE, + "%u\t%u\t%u\t%u\t%u\t%u\t%u - %u/%u/%u - %d\n", + rb->nr_entries, + rb->mem, + rb->subm, + rb->sync, + rb->l2p_update, +#ifdef CONFIG_NVM_PBLK_DEBUG + atomic_read(&rb->inflight_flush_point), +#else + 0, +#endif + rb->flush_point, + pblk_rb_read_count(rb), + pblk_rb_space(rb), + pblk_rb_flush_point_count(rb), + queued_entries); + else + offset = scnprintf(buf, PAGE_SIZE, + "%u\t%u\t%u\t%u\t%u\t%u\tNULL - %u/%u/%u - %d\n", + rb->nr_entries, + rb->mem, + rb->subm, + rb->sync, + rb->l2p_update, +#ifdef CONFIG_NVM_PBLK_DEBUG + atomic_read(&rb->inflight_flush_point), +#else + 0, +#endif + pblk_rb_read_count(rb), + pblk_rb_space(rb), + pblk_rb_flush_point_count(rb), + queued_entries); + + return offset; +} |