v4.19.13 snapshot.
diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c
new file mode 100644
index 0000000..f6eec02
--- /dev/null
+++ b/drivers/lightnvm/pblk-rb.c
@@ -0,0 +1,852 @@
+/*
+ * 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);
+
+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);
+}
+
+/*
+ * 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, struct pblk_rb_entry *rb_entry_base,
+ unsigned int power_size, unsigned int power_seg_sz)
+{
+ struct pblk *pblk = container_of(rb, struct pblk, rwb);
+ unsigned int init_entry = 0;
+ unsigned int alloc_order = power_size;
+ unsigned int max_order = MAX_ORDER - 1;
+ unsigned int order, iter;
+
+ down_write(&pblk_rb_lock);
+ rb->entries = rb_entry_base;
+ rb->seg_size = (1 << power_seg_sz);
+ rb->nr_entries = (1 << power_size);
+ rb->mem = rb->subm = rb->sync = rb->l2p_update = 0;
+ rb->flush_point = EMPTY_ENTRY;
+
+ spin_lock_init(&rb->w_lock);
+ spin_lock_init(&rb->s_lock);
+
+ INIT_LIST_HEAD(&rb->pages);
+
+ 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);
+ 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);
+ 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
+ * but user and GC I/O
+ */
+ pblk_rl_init(&pblk->rl, rb->nr_entries);
+
+ return 0;
+}
+
+/*
+ * pblk_rb_calculate_size -- calculate the size of the write buffer
+ */
+unsigned int pblk_rb_calculate_size(unsigned int nr_entries)
+{
+ /* Alloc a write buffer that can at least fit 128 entries */
+ return (1 << max(get_count_order(nr_entries), 7));
+}
+
+void *pblk_rb_entries_ref(struct pblk_rb *rb)
+{
+ return rb->entries;
+}
+
+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);
+}
+
+/*
+ * 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,
+ (subm + nr_entries) & (rb->nr_entries - 1));
+
+ 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->lines[pblk_ppa_to_line(w_ctx->ppa)];
+ kref_put(&line->ref, pblk_line_put);
+ clean_wctx(w_ctx);
+ rb->l2p_update = (rb->l2p_update + 1) & (rb->nr_entries - 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;
+
+ sync = READ_ONCE(rb->sync);
+ mem = READ_ONCE(rb->mem);
+
+ if (pblk_rb_ring_space(rb, mem, sync, rb->nr_entries) < nr_entries)
+ 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, (*pos + nr_entries) & (rb->nr_entries - 1));
+ 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 = (*pos + nr_entries) & (rb->nr_entries - 1);
+ *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;
+ }
+
+ 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 = (pos + 1) & (rb->nr_entries - 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, int bio_iter, bool advanced_bio)
+{
+ 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;
+ }
+
+ /* Only advance the bio if it hasn't been advanced already. If advanced,
+ * this bio is at least a partial bio (i.e., it has partially been
+ * filled with data from the cache). If part of the data resides on the
+ * media, we will read later on
+ */
+ if (unlikely(!advanced_bio))
+ bio_advance(bio, bio_iter * PBLK_EXPOSED_PAGE_SIZE);
+
+ 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 = pos & (rb->nr_entries - 1);
+
+ 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 = (sync + nr_entries) & (rb->nr_entries - 1);
+
+ /* 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;
+}
+
+/*
+ * Scan from the current position of the sync pointer to find the entry that
+ * corresponds to the given ppa. This is necessary since write requests can be
+ * completed out of order. The assumption is that the ppa is close to the sync
+ * pointer thus the search will not take long.
+ *
+ * The caller of this function must guarantee that the sync pointer will no
+ * reach the entry while it is using the metadata associated with it. With this
+ * assumption in mind, there is no need to take the sync lock.
+ */
+struct pblk_rb_entry *pblk_rb_sync_scan_entry(struct pblk_rb *rb,
+ struct ppa_addr *ppa)
+{
+ unsigned int sync, subm, count;
+ unsigned int i;
+
+ sync = READ_ONCE(rb->sync);
+ subm = READ_ONCE(rb->subm);
+ count = pblk_rb_ring_count(subm, sync, rb->nr_entries);
+
+ for (i = 0; i < count; i++)
+ sync = (sync + 1) & (rb->nr_entries - 1);
+
+ return NULL;
+}
+
+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(&rb->w_lock);
+ spin_unlock_irq(&rb->s_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;
+}