1 files changed, 555 insertions, 0 deletions

diff --git a/drivers/lightnvm/pblk-gc.c b/drivers/lightnvm/pblk-gc.c
new file mode 100644
index 000000000000..9b147cfd8a41
--- /dev/null
+++ b/drivers/lightnvm/pblk-gc.c
@@ -0,0 +1,555 @@
+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *                  Matias Bjorling <matias@cnexlabs.com>
+ *
+ * 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-gc.c - pblk's garbage collector
+ */
+
+#include "pblk.h"
+#include <linux/delay.h>
+
+static void pblk_gc_free_gc_rq(struct pblk_gc_rq *gc_rq)
+{
+	kfree(gc_rq->data);
+	kfree(gc_rq->lba_list);
+	kfree(gc_rq);
+}
+
+static int pblk_gc_write(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+	struct pblk_gc_rq *gc_rq, *tgc_rq;
+	LIST_HEAD(w_list);
+
+	spin_lock(&gc->w_lock);
+	if (list_empty(&gc->w_list)) {
+		spin_unlock(&gc->w_lock);
+		return 1;
+	}
+
+	list_for_each_entry_safe(gc_rq, tgc_rq, &gc->w_list, list) {
+		list_move_tail(&gc_rq->list, &w_list);
+		gc->w_entries--;
+	}
+	spin_unlock(&gc->w_lock);
+
+	list_for_each_entry_safe(gc_rq, tgc_rq, &w_list, list) {
+		pblk_write_gc_to_cache(pblk, gc_rq->data, gc_rq->lba_list,
+				gc_rq->nr_secs, gc_rq->secs_to_gc,
+				gc_rq->line, PBLK_IOTYPE_GC);
+
+		kref_put(&gc_rq->line->ref, pblk_line_put);
+
+		list_del(&gc_rq->list);
+		pblk_gc_free_gc_rq(gc_rq);
+	}
+
+	return 0;
+}
+
+static void pblk_gc_writer_kick(struct pblk_gc *gc)
+{
+	wake_up_process(gc->gc_writer_ts);
+}
+
+/*
+ * Responsible for managing all memory related to a gc request. Also in case of
+ * failure
+ */
+static int pblk_gc_move_valid_secs(struct pblk *pblk, struct pblk_line *line,
+				   u64 *lba_list, unsigned int nr_secs)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_gc *gc = &pblk->gc;
+	struct pblk_gc_rq *gc_rq;
+	void *data;
+	unsigned int secs_to_gc;
+	int ret = NVM_IO_OK;
+
+	data = kmalloc(nr_secs * geo->sec_size, GFP_KERNEL);
+	if (!data) {
+		ret = NVM_IO_ERR;
+		goto free_lba_list;
+	}
+
+	/* Read from GC victim block */
+	if (pblk_submit_read_gc(pblk, lba_list, data, nr_secs,
+							&secs_to_gc, line)) {
+		ret = NVM_IO_ERR;
+		goto free_data;
+	}
+
+	if (!secs_to_gc)
+		goto free_data;
+
+	gc_rq = kmalloc(sizeof(struct pblk_gc_rq), GFP_KERNEL);
+	if (!gc_rq) {
+		ret = NVM_IO_ERR;
+		goto free_data;
+	}
+
+	gc_rq->line = line;
+	gc_rq->data = data;
+	gc_rq->lba_list = lba_list;
+	gc_rq->nr_secs = nr_secs;
+	gc_rq->secs_to_gc = secs_to_gc;
+
+	kref_get(&line->ref);
+
+retry:
+	spin_lock(&gc->w_lock);
+	if (gc->w_entries > 256) {
+		spin_unlock(&gc->w_lock);
+		usleep_range(256, 1024);
+		goto retry;
+	}
+	gc->w_entries++;
+	list_add_tail(&gc_rq->list, &gc->w_list);
+	spin_unlock(&gc->w_lock);
+
+	pblk_gc_writer_kick(&pblk->gc);
+
+	return NVM_IO_OK;
+
+free_data:
+	kfree(data);
+free_lba_list:
+	kfree(lba_list);
+
+	return ret;
+}
+
+static void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct list_head *move_list;
+
+	spin_lock(&line->lock);
+	WARN_ON(line->state != PBLK_LINESTATE_GC);
+	line->state = PBLK_LINESTATE_CLOSED;
+	move_list = pblk_line_gc_list(pblk, line);
+	spin_unlock(&line->lock);
+
+	if (move_list) {
+		spin_lock(&l_mg->gc_lock);
+		list_add_tail(&line->list, move_list);
+		spin_unlock(&l_mg->gc_lock);
+	}
+}
+
+static void pblk_gc_line_ws(struct work_struct *work)
+{
+	struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
+									ws);
+	struct pblk *pblk = line_ws->pblk;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line *line = line_ws->line;
+	struct pblk_line_meta *lm = &pblk->lm;
+	__le64 *lba_list = line_ws->priv;
+	u64 *gc_list;
+	int sec_left;
+	int nr_ppas, bit;
+	int put_line = 1;
+
+	pr_debug("pblk: line '%d' being reclaimed for GC\n", line->id);
+
+	spin_lock(&line->lock);
+	sec_left = line->vsc;
+	if (!sec_left) {
+		/* Lines are erased before being used (l_mg->data_/log_next) */
+		spin_unlock(&line->lock);
+		goto out;
+	}
+	spin_unlock(&line->lock);
+
+	if (sec_left < 0) {
+		pr_err("pblk: corrupted GC line (%d)\n", line->id);
+		put_line = 0;
+		pblk_put_line_back(pblk, line);
+		goto out;
+	}
+
+	bit = -1;
+next_rq:
+	gc_list = kmalloc_array(pblk->max_write_pgs, sizeof(u64), GFP_KERNEL);
+	if (!gc_list) {
+		put_line = 0;
+		pblk_put_line_back(pblk, line);
+		goto out;
+	}
+
+	nr_ppas = 0;
+	do {
+		bit = find_next_zero_bit(line->invalid_bitmap, lm->sec_per_line,
+								bit + 1);
+		if (bit > line->emeta_ssec)
+			break;
+
+		gc_list[nr_ppas++] = le64_to_cpu(lba_list[bit]);
+	} while (nr_ppas < pblk->max_write_pgs);
+
+	if (unlikely(!nr_ppas)) {
+		kfree(gc_list);
+		goto out;
+	}
+
+	if (pblk_gc_move_valid_secs(pblk, line, gc_list, nr_ppas)) {
+		pr_err("pblk: could not GC all sectors: line:%d (%d/%d/%d)\n",
+						line->id, line->vsc,
+						nr_ppas, nr_ppas);
+		put_line = 0;
+		pblk_put_line_back(pblk, line);
+		goto out;
+	}
+
+	sec_left -= nr_ppas;
+	if (sec_left > 0)
+		goto next_rq;
+
+out:
+	pblk_mfree(line->emeta, l_mg->emeta_alloc_type);
+	mempool_free(line_ws, pblk->line_ws_pool);
+	atomic_dec(&pblk->gc.inflight_gc);
+	if (put_line)
+		kref_put(&line->ref, pblk_line_put);
+}
+
+static int pblk_gc_line(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_ws *line_ws;
+	__le64 *lba_list;
+	int ret;
+
+	line_ws = mempool_alloc(pblk->line_ws_pool, GFP_KERNEL);
+	line->emeta = pblk_malloc(lm->emeta_len, l_mg->emeta_alloc_type,
+								GFP_KERNEL);
+	if (!line->emeta) {
+		pr_err("pblk: cannot use GC emeta\n");
+		goto fail_free_ws;
+	}
+
+	ret = pblk_line_read_emeta(pblk, line);
+	if (ret) {
+		pr_err("pblk: line %d read emeta failed (%d)\n", line->id, ret);
+		goto fail_free_emeta;
+	}
+
+	/* If this read fails, it means that emeta is corrupted. For now, leave
+	 * the line untouched. TODO: Implement a recovery routine that scans and
+	 * moves all sectors on the line.
+	 */
+	lba_list = pblk_recov_get_lba_list(pblk, line->emeta);
+	if (!lba_list) {
+		pr_err("pblk: could not interpret emeta (line %d)\n", line->id);
+		goto fail_free_emeta;
+	}
+
+	line_ws->pblk = pblk;
+	line_ws->line = line;
+	line_ws->priv = lba_list;
+
+	INIT_WORK(&line_ws->ws, pblk_gc_line_ws);
+	queue_work(pblk->gc.gc_reader_wq, &line_ws->ws);
+
+	return 0;
+
+fail_free_emeta:
+	pblk_mfree(line->emeta, l_mg->emeta_alloc_type);
+fail_free_ws:
+	mempool_free(line_ws, pblk->line_ws_pool);
+	pblk_put_line_back(pblk, line);
+
+	return 1;
+}
+
+static void pblk_gc_lines(struct pblk *pblk, struct list_head *gc_list)
+{
+	struct pblk_line *line, *tline;
+
+	list_for_each_entry_safe(line, tline, gc_list, list) {
+		if (pblk_gc_line(pblk, line))
+			pr_err("pblk: failed to GC line %d\n", line->id);
+		list_del(&line->list);
+	}
+}
+
+/*
+ * Lines with no valid sectors will be returned to the free list immediately. If
+ * GC is activated - either because the free block count is under the determined
+ * threshold, or because it is being forced from user space - only lines with a
+ * high count of invalid sectors will be recycled.
+ */
+static void pblk_gc_run(struct pblk *pblk)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_gc *gc = &pblk->gc;
+	struct pblk_line *line, *tline;
+	unsigned int nr_blocks_free, nr_blocks_need;
+	struct list_head *group_list;
+	int run_gc, gc_group = 0;
+	int prev_gc = 0;
+	int inflight_gc = atomic_read(&gc->inflight_gc);
+	LIST_HEAD(gc_list);
+
+	spin_lock(&l_mg->gc_lock);
+	list_for_each_entry_safe(line, tline, &l_mg->gc_full_list, list) {
+		spin_lock(&line->lock);
+		WARN_ON(line->state != PBLK_LINESTATE_CLOSED);
+		line->state = PBLK_LINESTATE_GC;
+		spin_unlock(&line->lock);
+
+		list_del(&line->list);
+		kref_put(&line->ref, pblk_line_put);
+	}
+	spin_unlock(&l_mg->gc_lock);
+
+	nr_blocks_need = pblk_rl_gc_thrs(&pblk->rl);
+	nr_blocks_free = pblk_rl_nr_free_blks(&pblk->rl);
+	run_gc = (nr_blocks_need > nr_blocks_free || gc->gc_forced);
+
+next_gc_group:
+	group_list = l_mg->gc_lists[gc_group++];
+	spin_lock(&l_mg->gc_lock);
+	while (run_gc && !list_empty(group_list)) {
+		/* No need to queue up more GC lines than we can handle */
+		if (!run_gc || inflight_gc > gc->gc_jobs_active) {
+			spin_unlock(&l_mg->gc_lock);
+			pblk_gc_lines(pblk, &gc_list);
+			return;
+		}
+
+		line = list_first_entry(group_list, struct pblk_line, list);
+		nr_blocks_free += line->blk_in_line;
+
+		spin_lock(&line->lock);
+		WARN_ON(line->state != PBLK_LINESTATE_CLOSED);
+		line->state = PBLK_LINESTATE_GC;
+		list_move_tail(&line->list, &gc_list);
+		atomic_inc(&gc->inflight_gc);
+		inflight_gc++;
+		spin_unlock(&line->lock);
+
+		prev_gc = 1;
+		run_gc = (nr_blocks_need > nr_blocks_free || gc->gc_forced);
+	}
+	spin_unlock(&l_mg->gc_lock);
+
+	pblk_gc_lines(pblk, &gc_list);
+
+	if (!prev_gc && pblk->rl.rb_state > gc_group &&
+						gc_group < PBLK_NR_GC_LISTS)
+		goto next_gc_group;
+}
+
+
+static void pblk_gc_kick(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+
+	wake_up_process(gc->gc_ts);
+	pblk_gc_writer_kick(gc);
+	mod_timer(&gc->gc_timer, jiffies + msecs_to_jiffies(GC_TIME_MSECS));
+}
+
+static void pblk_gc_timer(unsigned long data)
+{
+	struct pblk *pblk = (struct pblk *)data;
+
+	pblk_gc_kick(pblk);
+}
+
+static int pblk_gc_ts(void *data)
+{
+	struct pblk *pblk = data;
+
+	while (!kthread_should_stop()) {
+		pblk_gc_run(pblk);
+		set_current_state(TASK_INTERRUPTIBLE);
+		io_schedule();
+	}
+
+	return 0;
+}
+
+static int pblk_gc_writer_ts(void *data)
+{
+	struct pblk *pblk = data;
+
+	while (!kthread_should_stop()) {
+		if (!pblk_gc_write(pblk))
+			continue;
+		set_current_state(TASK_INTERRUPTIBLE);
+		io_schedule();
+	}
+
+	return 0;
+}
+
+static void pblk_gc_start(struct pblk *pblk)
+{
+	pblk->gc.gc_active = 1;
+
+	pr_debug("pblk: gc start\n");
+}
+
+int pblk_gc_status(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+	int ret;
+
+	spin_lock(&gc->lock);
+	ret = gc->gc_active;
+	spin_unlock(&gc->lock);
+
+	return ret;
+}
+
+static void __pblk_gc_should_start(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+
+	lockdep_assert_held(&gc->lock);
+
+	if (gc->gc_enabled && !gc->gc_active)
+		pblk_gc_start(pblk);
+}
+
+void pblk_gc_should_start(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+
+	spin_lock(&gc->lock);
+	__pblk_gc_should_start(pblk);
+	spin_unlock(&gc->lock);
+}
+
+/*
+ * If flush_wq == 1 then no lock should be held by the caller since
+ * flush_workqueue can sleep
+ */
+static void pblk_gc_stop(struct pblk *pblk, int flush_wq)
+{
+	spin_lock(&pblk->gc.lock);
+	pblk->gc.gc_active = 0;
+	spin_unlock(&pblk->gc.lock);
+
+	pr_debug("pblk: gc stop\n");
+}
+
+void pblk_gc_should_stop(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+
+	if (gc->gc_active && !gc->gc_forced)
+		pblk_gc_stop(pblk, 0);
+}
+
+void pblk_gc_sysfs_state_show(struct pblk *pblk, int *gc_enabled,
+			      int *gc_active)
+{
+	struct pblk_gc *gc = &pblk->gc;
+
+	spin_lock(&gc->lock);
+	*gc_enabled = gc->gc_enabled;
+	*gc_active = gc->gc_active;
+	spin_unlock(&gc->lock);
+}
+
+void pblk_gc_sysfs_force(struct pblk *pblk, int force)
+{
+	struct pblk_gc *gc = &pblk->gc;
+	int rsv = 0;
+
+	spin_lock(&gc->lock);
+	if (force) {
+		gc->gc_enabled = 1;
+		rsv = 64;
+	}
+	pblk_rl_set_gc_rsc(&pblk->rl, rsv);
+	gc->gc_forced = force;
+	__pblk_gc_should_start(pblk);
+	spin_unlock(&gc->lock);
+}
+
+int pblk_gc_init(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+	int ret;
+
+	gc->gc_ts = kthread_create(pblk_gc_ts, pblk, "pblk-gc-ts");
+	if (IS_ERR(gc->gc_ts)) {
+		pr_err("pblk: could not allocate GC main kthread\n");
+		return PTR_ERR(gc->gc_ts);
+	}
+
+	gc->gc_writer_ts = kthread_create(pblk_gc_writer_ts, pblk,
+							"pblk-gc-writer-ts");
+	if (IS_ERR(gc->gc_writer_ts)) {
+		pr_err("pblk: could not allocate GC writer kthread\n");
+		ret = PTR_ERR(gc->gc_writer_ts);
+		goto fail_free_main_kthread;
+	}
+
+	setup_timer(&gc->gc_timer, pblk_gc_timer, (unsigned long)pblk);
+	mod_timer(&gc->gc_timer, jiffies + msecs_to_jiffies(GC_TIME_MSECS));
+
+	gc->gc_active = 0;
+	gc->gc_forced = 0;
+	gc->gc_enabled = 1;
+	gc->gc_jobs_active = 8;
+	gc->w_entries = 0;
+	atomic_set(&gc->inflight_gc, 0);
+
+	gc->gc_reader_wq = alloc_workqueue("pblk-gc-reader-wq",
+			WQ_MEM_RECLAIM | WQ_UNBOUND, gc->gc_jobs_active);
+	if (!gc->gc_reader_wq) {
+		pr_err("pblk: could not allocate GC reader workqueue\n");
+		ret = -ENOMEM;
+		goto fail_free_writer_kthread;
+	}
+
+	spin_lock_init(&gc->lock);
+	spin_lock_init(&gc->w_lock);
+	INIT_LIST_HEAD(&gc->w_list);
+
+	return 0;
+
+fail_free_main_kthread:
+	kthread_stop(gc->gc_ts);
+fail_free_writer_kthread:
+	kthread_stop(gc->gc_writer_ts);
+
+	return ret;
+}
+
+void pblk_gc_exit(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+
+	flush_workqueue(gc->gc_reader_wq);
+
+	del_timer(&gc->gc_timer);
+	pblk_gc_stop(pblk, 1);
+
+	if (gc->gc_ts)
+		kthread_stop(gc->gc_ts);
+
+	if (pblk->gc.gc_reader_wq)
+		destroy_workqueue(pblk->gc.gc_reader_wq);
+
+	if (gc->gc_writer_ts)
+		kthread_stop(gc->gc_writer_ts);
+}