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![Igor Konopko](/assets/img/avatar_default.png)
This patch changes the approach to handling partial read path. In old approach merging of data from round buffer and drive was fully made by drive. This had some disadvantages - code was complex and relies on bio internals, so it was hard to maintain and was strongly dependent on bio changes. In new approach most of the handling is done mostly by block layer functions such as bio_split(), bio_chain() and generic_make request() and generally is less complex and easier to maintain. Below some more details of the new approach. When read bio arrives, it is cloned for pblk internal purposes. All the L2P mapping, which includes copying data from round buffer to bio and thus bio_advance() calls is done on the cloned bio, so the original bio is untouched. If we found that we have partial read case, we still have original bio untouched, so we can split it and continue to process only first part of it in current context, when the rest will be called as separate bio request which is passed to generic_make_request() for further processing. Signed-off-by: Igor Konopko <igor.j.konopko@intel.com> Reviewed-by: Heiner Litz <hlitz@ucsc.edu> Reviewed-by: Javier González <javier@javigon.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
858 lines
21 KiB
C
858 lines
21 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2016 CNEX Labs
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* Initial release: Javier Gonzalez <javier@cnexlabs.com>
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*
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* Based upon the circular ringbuffer.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version
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* 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* pblk-rb.c - pblk's write buffer
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*/
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#include <linux/circ_buf.h>
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#include "pblk.h"
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static DECLARE_RWSEM(pblk_rb_lock);
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static void pblk_rb_data_free(struct pblk_rb *rb)
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{
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struct pblk_rb_pages *p, *t;
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down_write(&pblk_rb_lock);
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list_for_each_entry_safe(p, t, &rb->pages, list) {
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free_pages((unsigned long)page_address(p->pages), p->order);
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list_del(&p->list);
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kfree(p);
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}
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up_write(&pblk_rb_lock);
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}
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void pblk_rb_free(struct pblk_rb *rb)
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{
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pblk_rb_data_free(rb);
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vfree(rb->entries);
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}
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/*
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* pblk_rb_calculate_size -- calculate the size of the write buffer
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*/
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static unsigned int pblk_rb_calculate_size(unsigned int nr_entries,
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unsigned int threshold)
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{
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unsigned int thr_sz = 1 << (get_count_order(threshold + NVM_MAX_VLBA));
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unsigned int max_sz = max(thr_sz, nr_entries);
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unsigned int max_io;
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/* Alloc a write buffer that can (i) fit at least two split bios
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* (considering max I/O size NVM_MAX_VLBA, and (ii) guarantee that the
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* threshold will be respected
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*/
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max_io = (1 << max((int)(get_count_order(max_sz)),
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(int)(get_count_order(NVM_MAX_VLBA << 1))));
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if ((threshold + NVM_MAX_VLBA) >= max_io)
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max_io <<= 1;
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return max_io;
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}
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/*
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* Initialize ring buffer. The data and metadata buffers must be previously
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* allocated and their size must be a power of two
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* (Documentation/core-api/circular-buffers.rst)
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*/
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int pblk_rb_init(struct pblk_rb *rb, unsigned int size, unsigned int threshold,
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unsigned int seg_size)
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{
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struct pblk *pblk = container_of(rb, struct pblk, rwb);
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struct pblk_rb_entry *entries;
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unsigned int init_entry = 0;
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unsigned int max_order = MAX_ORDER - 1;
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unsigned int power_size, power_seg_sz;
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unsigned int alloc_order, order, iter;
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unsigned int nr_entries;
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nr_entries = pblk_rb_calculate_size(size, threshold);
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entries = vzalloc(array_size(nr_entries, sizeof(struct pblk_rb_entry)));
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if (!entries)
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return -ENOMEM;
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power_size = get_count_order(nr_entries);
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power_seg_sz = get_count_order(seg_size);
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down_write(&pblk_rb_lock);
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rb->entries = entries;
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rb->seg_size = (1 << power_seg_sz);
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rb->nr_entries = (1 << power_size);
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rb->mem = rb->subm = rb->sync = rb->l2p_update = 0;
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rb->back_thres = threshold;
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rb->flush_point = EMPTY_ENTRY;
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spin_lock_init(&rb->w_lock);
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spin_lock_init(&rb->s_lock);
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INIT_LIST_HEAD(&rb->pages);
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alloc_order = power_size;
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if (alloc_order >= max_order) {
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order = max_order;
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iter = (1 << (alloc_order - max_order));
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} else {
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order = alloc_order;
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iter = 1;
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}
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do {
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struct pblk_rb_entry *entry;
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struct pblk_rb_pages *page_set;
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void *kaddr;
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unsigned long set_size;
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int i;
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page_set = kmalloc(sizeof(struct pblk_rb_pages), GFP_KERNEL);
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if (!page_set) {
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up_write(&pblk_rb_lock);
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vfree(entries);
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return -ENOMEM;
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}
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page_set->order = order;
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page_set->pages = alloc_pages(GFP_KERNEL, order);
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if (!page_set->pages) {
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kfree(page_set);
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pblk_rb_data_free(rb);
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up_write(&pblk_rb_lock);
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vfree(entries);
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return -ENOMEM;
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}
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kaddr = page_address(page_set->pages);
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entry = &rb->entries[init_entry];
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entry->data = kaddr;
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entry->cacheline = pblk_cacheline_to_addr(init_entry++);
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entry->w_ctx.flags = PBLK_WRITABLE_ENTRY;
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set_size = (1 << order);
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for (i = 1; i < set_size; i++) {
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entry = &rb->entries[init_entry];
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entry->cacheline = pblk_cacheline_to_addr(init_entry++);
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entry->data = kaddr + (i * rb->seg_size);
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entry->w_ctx.flags = PBLK_WRITABLE_ENTRY;
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bio_list_init(&entry->w_ctx.bios);
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}
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list_add_tail(&page_set->list, &rb->pages);
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iter--;
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} while (iter > 0);
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up_write(&pblk_rb_lock);
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#ifdef CONFIG_NVM_PBLK_DEBUG
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atomic_set(&rb->inflight_flush_point, 0);
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#endif
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/*
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* Initialize rate-limiter, which controls access to the write buffer
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* by user and GC I/O
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*/
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pblk_rl_init(&pblk->rl, rb->nr_entries, threshold);
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return 0;
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}
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static void clean_wctx(struct pblk_w_ctx *w_ctx)
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{
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int flags;
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flags = READ_ONCE(w_ctx->flags);
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WARN_ONCE(!(flags & PBLK_SUBMITTED_ENTRY),
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"pblk: overwriting unsubmitted data\n");
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/* Release flags on context. Protect from writes and reads */
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smp_store_release(&w_ctx->flags, PBLK_WRITABLE_ENTRY);
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pblk_ppa_set_empty(&w_ctx->ppa);
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w_ctx->lba = ADDR_EMPTY;
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}
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#define pblk_rb_ring_count(head, tail, size) CIRC_CNT(head, tail, size)
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#define pblk_rb_ring_space(rb, head, tail, size) \
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(CIRC_SPACE(head, tail, size))
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/*
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* Buffer space is calculated with respect to the back pointer signaling
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* synchronized entries to the media.
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*/
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static unsigned int pblk_rb_space(struct pblk_rb *rb)
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{
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unsigned int mem = READ_ONCE(rb->mem);
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unsigned int sync = READ_ONCE(rb->sync);
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return pblk_rb_ring_space(rb, mem, sync, rb->nr_entries);
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}
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unsigned int pblk_rb_ptr_wrap(struct pblk_rb *rb, unsigned int p,
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unsigned int nr_entries)
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{
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return (p + nr_entries) & (rb->nr_entries - 1);
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}
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/*
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* Buffer count is calculated with respect to the submission entry signaling the
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* entries that are available to send to the media
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*/
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unsigned int pblk_rb_read_count(struct pblk_rb *rb)
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{
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unsigned int mem = READ_ONCE(rb->mem);
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unsigned int subm = READ_ONCE(rb->subm);
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return pblk_rb_ring_count(mem, subm, rb->nr_entries);
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}
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unsigned int pblk_rb_sync_count(struct pblk_rb *rb)
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{
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unsigned int mem = READ_ONCE(rb->mem);
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unsigned int sync = READ_ONCE(rb->sync);
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return pblk_rb_ring_count(mem, sync, rb->nr_entries);
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}
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unsigned int pblk_rb_read_commit(struct pblk_rb *rb, unsigned int nr_entries)
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{
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unsigned int subm;
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subm = READ_ONCE(rb->subm);
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/* Commit read means updating submission pointer */
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smp_store_release(&rb->subm, pblk_rb_ptr_wrap(rb, subm, nr_entries));
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return subm;
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}
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static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int to_update)
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{
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struct pblk *pblk = container_of(rb, struct pblk, rwb);
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struct pblk_line *line;
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struct pblk_rb_entry *entry;
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struct pblk_w_ctx *w_ctx;
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unsigned int user_io = 0, gc_io = 0;
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unsigned int i;
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int flags;
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for (i = 0; i < to_update; i++) {
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entry = &rb->entries[rb->l2p_update];
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w_ctx = &entry->w_ctx;
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flags = READ_ONCE(entry->w_ctx.flags);
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if (flags & PBLK_IOTYPE_USER)
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user_io++;
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else if (flags & PBLK_IOTYPE_GC)
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gc_io++;
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else
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WARN(1, "pblk: unknown IO type\n");
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pblk_update_map_dev(pblk, w_ctx->lba, w_ctx->ppa,
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entry->cacheline);
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line = pblk_ppa_to_line(pblk, w_ctx->ppa);
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atomic_dec(&line->sec_to_update);
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kref_put(&line->ref, pblk_line_put);
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clean_wctx(w_ctx);
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rb->l2p_update = pblk_rb_ptr_wrap(rb, rb->l2p_update, 1);
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}
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pblk_rl_out(&pblk->rl, user_io, gc_io);
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return 0;
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}
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/*
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* When we move the l2p_update pointer, we update the l2p table - lookups will
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* point to the physical address instead of to the cacheline in the write buffer
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* from this moment on.
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*/
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static int pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int nr_entries,
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unsigned int mem, unsigned int sync)
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{
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unsigned int space, count;
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int ret = 0;
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lockdep_assert_held(&rb->w_lock);
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/* Update l2p only as buffer entries are being overwritten */
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space = pblk_rb_ring_space(rb, mem, rb->l2p_update, rb->nr_entries);
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if (space > nr_entries)
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goto out;
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count = nr_entries - space;
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/* l2p_update used exclusively under rb->w_lock */
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ret = __pblk_rb_update_l2p(rb, count);
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out:
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return ret;
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}
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/*
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* Update the l2p entry for all sectors stored on the write buffer. This means
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* that all future lookups to the l2p table will point to a device address, not
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* to the cacheline in the write buffer.
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*/
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void pblk_rb_sync_l2p(struct pblk_rb *rb)
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{
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unsigned int sync;
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unsigned int to_update;
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spin_lock(&rb->w_lock);
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/* Protect from reads and writes */
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sync = smp_load_acquire(&rb->sync);
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to_update = pblk_rb_ring_count(sync, rb->l2p_update, rb->nr_entries);
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__pblk_rb_update_l2p(rb, to_update);
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spin_unlock(&rb->w_lock);
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}
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/*
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* Write @nr_entries to ring buffer from @data buffer if there is enough space.
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* Typically, 4KB data chunks coming from a bio will be copied to the ring
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* buffer, thus the write will fail if not all incoming data can be copied.
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*
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*/
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static void __pblk_rb_write_entry(struct pblk_rb *rb, void *data,
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struct pblk_w_ctx w_ctx,
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struct pblk_rb_entry *entry)
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{
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memcpy(entry->data, data, rb->seg_size);
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entry->w_ctx.lba = w_ctx.lba;
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entry->w_ctx.ppa = w_ctx.ppa;
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}
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void pblk_rb_write_entry_user(struct pblk_rb *rb, void *data,
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struct pblk_w_ctx w_ctx, unsigned int ring_pos)
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{
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struct pblk *pblk = container_of(rb, struct pblk, rwb);
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struct pblk_rb_entry *entry;
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int flags;
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entry = &rb->entries[ring_pos];
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flags = READ_ONCE(entry->w_ctx.flags);
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#ifdef CONFIG_NVM_PBLK_DEBUG
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/* Caller must guarantee that the entry is free */
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BUG_ON(!(flags & PBLK_WRITABLE_ENTRY));
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#endif
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__pblk_rb_write_entry(rb, data, w_ctx, entry);
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pblk_update_map_cache(pblk, w_ctx.lba, entry->cacheline);
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flags = w_ctx.flags | PBLK_WRITTEN_DATA;
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/* Release flags on write context. Protect from writes */
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smp_store_release(&entry->w_ctx.flags, flags);
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}
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void pblk_rb_write_entry_gc(struct pblk_rb *rb, void *data,
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struct pblk_w_ctx w_ctx, struct pblk_line *line,
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u64 paddr, unsigned int ring_pos)
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{
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struct pblk *pblk = container_of(rb, struct pblk, rwb);
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struct pblk_rb_entry *entry;
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int flags;
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entry = &rb->entries[ring_pos];
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flags = READ_ONCE(entry->w_ctx.flags);
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#ifdef CONFIG_NVM_PBLK_DEBUG
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/* Caller must guarantee that the entry is free */
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BUG_ON(!(flags & PBLK_WRITABLE_ENTRY));
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#endif
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__pblk_rb_write_entry(rb, data, w_ctx, entry);
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if (!pblk_update_map_gc(pblk, w_ctx.lba, entry->cacheline, line, paddr))
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entry->w_ctx.lba = ADDR_EMPTY;
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flags = w_ctx.flags | PBLK_WRITTEN_DATA;
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/* Release flags on write context. Protect from writes */
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smp_store_release(&entry->w_ctx.flags, flags);
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}
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static int pblk_rb_flush_point_set(struct pblk_rb *rb, struct bio *bio,
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unsigned int pos)
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{
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struct pblk_rb_entry *entry;
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unsigned int sync, flush_point;
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pblk_rb_sync_init(rb, NULL);
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sync = READ_ONCE(rb->sync);
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if (pos == sync) {
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pblk_rb_sync_end(rb, NULL);
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return 0;
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}
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#ifdef CONFIG_NVM_PBLK_DEBUG
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atomic_inc(&rb->inflight_flush_point);
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#endif
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flush_point = (pos == 0) ? (rb->nr_entries - 1) : (pos - 1);
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entry = &rb->entries[flush_point];
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/* Protect flush points */
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smp_store_release(&rb->flush_point, flush_point);
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if (bio)
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bio_list_add(&entry->w_ctx.bios, bio);
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pblk_rb_sync_end(rb, NULL);
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return bio ? 1 : 0;
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}
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static int __pblk_rb_may_write(struct pblk_rb *rb, unsigned int nr_entries,
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unsigned int *pos)
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{
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unsigned int mem;
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unsigned int sync;
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unsigned int threshold;
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sync = READ_ONCE(rb->sync);
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mem = READ_ONCE(rb->mem);
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threshold = nr_entries + rb->back_thres;
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if (pblk_rb_ring_space(rb, mem, sync, rb->nr_entries) < threshold)
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return 0;
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if (pblk_rb_update_l2p(rb, nr_entries, mem, sync))
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return 0;
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*pos = mem;
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return 1;
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}
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static int pblk_rb_may_write(struct pblk_rb *rb, unsigned int nr_entries,
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unsigned int *pos)
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{
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if (!__pblk_rb_may_write(rb, nr_entries, pos))
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return 0;
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/* Protect from read count */
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smp_store_release(&rb->mem, pblk_rb_ptr_wrap(rb, *pos, nr_entries));
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return 1;
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}
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void pblk_rb_flush(struct pblk_rb *rb)
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{
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struct pblk *pblk = container_of(rb, struct pblk, rwb);
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unsigned int mem = READ_ONCE(rb->mem);
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if (pblk_rb_flush_point_set(rb, NULL, mem))
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return;
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pblk_write_kick(pblk);
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}
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static int pblk_rb_may_write_flush(struct pblk_rb *rb, unsigned int nr_entries,
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unsigned int *pos, struct bio *bio,
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int *io_ret)
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{
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unsigned int mem;
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if (!__pblk_rb_may_write(rb, nr_entries, pos))
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return 0;
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mem = pblk_rb_ptr_wrap(rb, *pos, nr_entries);
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*io_ret = NVM_IO_DONE;
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if (bio->bi_opf & REQ_PREFLUSH) {
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struct pblk *pblk = container_of(rb, struct pblk, rwb);
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atomic64_inc(&pblk->nr_flush);
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if (pblk_rb_flush_point_set(&pblk->rwb, bio, mem))
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*io_ret = NVM_IO_OK;
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}
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/* Protect from read count */
|
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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;
|
|
}
|