1 files changed, 445 insertions, 0 deletions
diff --git a/drivers/md/dm-pcache/cache.c b/drivers/md/dm-pcache/cache.c
new file mode 100644
index 000000000000..d8e92367d947
--- /dev/null
+++ b/drivers/md/dm-pcache/cache.c
@@ -0,0 +1,445 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/blk_types.h>
+
+#include "cache.h"
+#include "cache_dev.h"
+#include "backing_dev.h"
+#include "dm_pcache.h"
+
+struct kmem_cache *key_cache;
+
+static inline struct pcache_cache_info *get_cache_info_addr(struct pcache_cache *cache)
+{
+	return cache->cache_info_addr + cache->info_index;
+}
+
+static void cache_info_write(struct pcache_cache *cache)
+{
+	struct pcache_cache_info *cache_info = &cache->cache_info;
+
+	cache_info->header.seq++;
+	cache_info->header.crc = pcache_meta_crc(&cache_info->header,
+						sizeof(struct pcache_cache_info));
+
+	memcpy_flushcache(get_cache_info_addr(cache), cache_info,
+			sizeof(struct pcache_cache_info));
+
+	cache->info_index = (cache->info_index + 1) % PCACHE_META_INDEX_MAX;
+}
+
+static void cache_info_init_default(struct pcache_cache *cache);
+static int cache_info_init(struct pcache_cache *cache, struct pcache_cache_options *opts)
+{
+	struct dm_pcache *pcache = CACHE_TO_PCACHE(cache);
+	struct pcache_cache_info *cache_info_addr;
+
+	cache_info_addr = pcache_meta_find_latest(&cache->cache_info_addr->header,
+						sizeof(struct pcache_cache_info),
+						PCACHE_CACHE_INFO_SIZE,
+						&cache->cache_info);
+	if (IS_ERR(cache_info_addr))
+		return PTR_ERR(cache_info_addr);
+
+	if (cache_info_addr) {
+		if (opts->data_crc !=
+				(cache->cache_info.flags & PCACHE_CACHE_FLAGS_DATA_CRC)) {
+			pcache_dev_err(pcache, "invalid option for data_crc: %s, expected: %s",
+					opts->data_crc ? "true" : "false",
+					cache->cache_info.flags & PCACHE_CACHE_FLAGS_DATA_CRC ? "true" : "false");
+			return -EINVAL;
+		}
+
+		return 0;
+	}
+
+	/* init cache_info for new cache */
+	cache_info_init_default(cache);
+	cache_mode_set(cache, opts->cache_mode);
+	if (opts->data_crc)
+		cache->cache_info.flags |= PCACHE_CACHE_FLAGS_DATA_CRC;
+
+	return 0;
+}
+
+static void cache_info_set_gc_percent(struct pcache_cache_info *cache_info, u8 percent)
+{
+	cache_info->flags &= ~PCACHE_CACHE_FLAGS_GC_PERCENT_MASK;
+	cache_info->flags |= FIELD_PREP(PCACHE_CACHE_FLAGS_GC_PERCENT_MASK, percent);
+}
+
+int pcache_cache_set_gc_percent(struct pcache_cache *cache, u8 percent)
+{
+	if (percent > PCACHE_CACHE_GC_PERCENT_MAX || percent < PCACHE_CACHE_GC_PERCENT_MIN)
+		return -EINVAL;
+
+	mutex_lock(&cache->cache_info_lock);
+	cache_info_set_gc_percent(&cache->cache_info, percent);
+
+	cache_info_write(cache);
+	mutex_unlock(&cache->cache_info_lock);
+
+	return 0;
+}
+
+void cache_pos_encode(struct pcache_cache *cache,
+			     struct pcache_cache_pos_onmedia *pos_onmedia_base,
+			     struct pcache_cache_pos *pos, u64 seq, u32 *index)
+{
+	struct pcache_cache_pos_onmedia pos_onmedia;
+	struct pcache_cache_pos_onmedia *pos_onmedia_addr = pos_onmedia_base + *index;
+
+	pos_onmedia.cache_seg_id = pos->cache_seg->cache_seg_id;
+	pos_onmedia.seg_off = pos->seg_off;
+	pos_onmedia.header.seq = seq;
+	pos_onmedia.header.crc = cache_pos_onmedia_crc(&pos_onmedia);
+
+	memcpy_flushcache(pos_onmedia_addr, &pos_onmedia, sizeof(struct pcache_cache_pos_onmedia));
+	pmem_wmb();
+
+	*index = (*index + 1) % PCACHE_META_INDEX_MAX;
+}
+
+int cache_pos_decode(struct pcache_cache *cache,
+			    struct pcache_cache_pos_onmedia *pos_onmedia,
+			    struct pcache_cache_pos *pos, u64 *seq, u32 *index)
+{
+	struct pcache_cache_pos_onmedia latest, *latest_addr;
+
+	latest_addr = pcache_meta_find_latest(&pos_onmedia->header,
+					sizeof(struct pcache_cache_pos_onmedia),
+					sizeof(struct pcache_cache_pos_onmedia),
+					&latest);
+	if (IS_ERR(latest_addr))
+		return PTR_ERR(latest_addr);
+
+	if (!latest_addr)
+		return -EIO;
+
+	pos->cache_seg = &cache->segments[latest.cache_seg_id];
+	pos->seg_off = latest.seg_off;
+	*seq = latest.header.seq;
+	*index = (latest_addr - pos_onmedia);
+
+	return 0;
+}
+
+static inline void cache_info_set_seg_id(struct pcache_cache *cache, u32 seg_id)
+{
+	cache->cache_info.seg_id = seg_id;
+}
+
+static int cache_init(struct dm_pcache *pcache)
+{
+	struct pcache_cache *cache = &pcache->cache;
+	struct pcache_backing_dev *backing_dev = &pcache->backing_dev;
+	struct pcache_cache_dev *cache_dev = &pcache->cache_dev;
+	int ret;
+
+	cache->segments = kvcalloc(cache_dev->seg_num, sizeof(struct pcache_cache_segment), GFP_KERNEL);
+	if (!cache->segments) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	cache->seg_map = kvcalloc(BITS_TO_LONGS(cache_dev->seg_num), sizeof(unsigned long), GFP_KERNEL);
+	if (!cache->seg_map) {
+		ret = -ENOMEM;
+		goto free_segments;
+	}
+
+	cache->backing_dev = backing_dev;
+	cache->cache_dev = &pcache->cache_dev;
+	cache->n_segs = cache_dev->seg_num;
+	atomic_set(&cache->gc_errors, 0);
+	spin_lock_init(&cache->seg_map_lock);
+	spin_lock_init(&cache->key_head_lock);
+
+	mutex_init(&cache->cache_info_lock);
+	mutex_init(&cache->key_tail_lock);
+	mutex_init(&cache->dirty_tail_lock);
+	mutex_init(&cache->writeback_lock);
+
+	INIT_DELAYED_WORK(&cache->writeback_work, cache_writeback_fn);
+	INIT_DELAYED_WORK(&cache->gc_work, pcache_cache_gc_fn);
+	INIT_WORK(&cache->clean_work, clean_fn);
+
+	return 0;
+
+free_segments:
+	kvfree(cache->segments);
+err:
+	return ret;
+}
+
+static void cache_exit(struct pcache_cache *cache)
+{
+	kvfree(cache->seg_map);
+	kvfree(cache->segments);
+}
+
+static void cache_info_init_default(struct pcache_cache *cache)
+{
+	struct pcache_cache_info *cache_info = &cache->cache_info;
+
+	cache_info->header.seq = 0;
+	cache_info->n_segs = cache->cache_dev->seg_num;
+	cache_info_set_gc_percent(cache_info, PCACHE_CACHE_GC_PERCENT_DEFAULT);
+}
+
+static int cache_tail_init(struct pcache_cache *cache)
+{
+	struct dm_pcache *pcache = CACHE_TO_PCACHE(cache);
+	bool new_cache = !(cache->cache_info.flags & PCACHE_CACHE_FLAGS_INIT_DONE);
+
+	if (new_cache) {
+		__set_bit(0, cache->seg_map);
+
+		cache->key_head.cache_seg = &cache->segments[0];
+		cache->key_head.seg_off = 0;
+		cache_pos_copy(&cache->key_tail, &cache->key_head);
+		cache_pos_copy(&cache->dirty_tail, &cache->key_head);
+
+		cache_encode_dirty_tail(cache);
+		cache_encode_key_tail(cache);
+	} else {
+		if (cache_decode_key_tail(cache) || cache_decode_dirty_tail(cache)) {
+			pcache_dev_err(pcache, "Corrupted key tail or dirty tail.\n");
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+static int get_seg_id(struct pcache_cache *cache,
+		      struct pcache_cache_segment *prev_cache_seg,
+		      bool new_cache, u32 *seg_id)
+{
+	struct dm_pcache *pcache = CACHE_TO_PCACHE(cache);
+	struct pcache_cache_dev *cache_dev = cache->cache_dev;
+	int ret;
+
+	if (new_cache) {
+		ret = cache_dev_get_empty_segment_id(cache_dev, seg_id);
+		if (ret) {
+			pcache_dev_err(pcache, "no available segment\n");
+			goto err;
+		}
+
+		if (prev_cache_seg)
+			cache_seg_set_next_seg(prev_cache_seg, *seg_id);
+		else
+			cache_info_set_seg_id(cache, *seg_id);
+	} else {
+		if (prev_cache_seg) {
+			struct pcache_segment_info *prev_seg_info;
+
+			prev_seg_info = &prev_cache_seg->cache_seg_info;
+			if (!segment_info_has_next(prev_seg_info)) {
+				ret = -EFAULT;
+				goto err;
+			}
+			*seg_id = prev_cache_seg->cache_seg_info.next_seg;
+		} else {
+			*seg_id = cache->cache_info.seg_id;
+		}
+	}
+	return 0;
+err:
+	return ret;
+}
+
+static int cache_segs_init(struct pcache_cache *cache)
+{
+	struct pcache_cache_segment *prev_cache_seg = NULL;
+	struct pcache_cache_info *cache_info = &cache->cache_info;
+	bool new_cache = !(cache->cache_info.flags & PCACHE_CACHE_FLAGS_INIT_DONE);
+	u32 seg_id;
+	int ret;
+	u32 i;
+
+	for (i = 0; i < cache_info->n_segs; i++) {
+		ret = get_seg_id(cache, prev_cache_seg, new_cache, &seg_id);
+		if (ret)
+			goto err;
+
+		ret = cache_seg_init(cache, seg_id, i, new_cache);
+		if (ret)
+			goto err;
+
+		prev_cache_seg = &cache->segments[i];
+	}
+	return 0;
+err:
+	return ret;
+}
+
+static int cache_init_req_keys(struct pcache_cache *cache, u32 n_paral)
+{
+	struct dm_pcache *pcache = CACHE_TO_PCACHE(cache);
+	u32 n_subtrees;
+	int ret;
+	u32 i, cpu;
+
+	/* Calculate number of cache trees based on the device size */
+	n_subtrees = DIV_ROUND_UP(cache->dev_size << SECTOR_SHIFT, PCACHE_CACHE_SUBTREE_SIZE);
+	ret = cache_tree_init(cache, &cache->req_key_tree, n_subtrees);
+	if (ret)
+		goto err;
+
+	cache->n_ksets = n_paral;
+	cache->ksets = kvcalloc(cache->n_ksets, PCACHE_KSET_SIZE, GFP_KERNEL);
+	if (!cache->ksets) {
+		ret = -ENOMEM;
+		goto req_tree_exit;
+	}
+
+	/*
+	 * Initialize each kset with a spinlock and delayed work for flushing.
+	 * Each kset is associated with one queue to ensure independent handling
+	 * of cache keys across multiple queues, maximizing multiqueue concurrency.
+	 */
+	for (i = 0; i < cache->n_ksets; i++) {
+		struct pcache_cache_kset *kset = get_kset(cache, i);
+
+		kset->cache = cache;
+		spin_lock_init(&kset->kset_lock);
+		INIT_DELAYED_WORK(&kset->flush_work, kset_flush_fn);
+	}
+
+	cache->data_heads = alloc_percpu(struct pcache_cache_data_head);
+	if (!cache->data_heads) {
+		ret = -ENOMEM;
+		goto free_kset;
+	}
+
+	for_each_possible_cpu(cpu) {
+		struct pcache_cache_data_head *h =
+			per_cpu_ptr(cache->data_heads, cpu);
+		h->head_pos.cache_seg = NULL;
+	}
+
+	/*
+	 * Replay persisted cache keys using cache_replay.
+	 * This function loads and replays cache keys from previously stored
+	 * ksets, allowing the cache to restore its state after a restart.
+	 */
+	ret = cache_replay(cache);
+	if (ret) {
+		pcache_dev_err(pcache, "failed to replay keys\n");
+		goto free_heads;
+	}
+
+	return 0;
+
+free_heads:
+	free_percpu(cache->data_heads);
+free_kset:
+	kvfree(cache->ksets);
+req_tree_exit:
+	cache_tree_exit(&cache->req_key_tree);
+err:
+	return ret;
+}
+
+static void cache_destroy_req_keys(struct pcache_cache *cache)
+{
+	u32 i;
+
+	for (i = 0; i < cache->n_ksets; i++) {
+		struct pcache_cache_kset *kset = get_kset(cache, i);
+
+		cancel_delayed_work_sync(&kset->flush_work);
+	}
+
+	free_percpu(cache->data_heads);
+	kvfree(cache->ksets);
+	cache_tree_exit(&cache->req_key_tree);
+}
+
+int pcache_cache_start(struct dm_pcache *pcache)
+{
+	struct pcache_backing_dev *backing_dev = &pcache->backing_dev;
+	struct pcache_cache *cache = &pcache->cache;
+	struct pcache_cache_options *opts = &pcache->opts;
+	int ret;
+
+	ret = cache_init(pcache);
+	if (ret)
+		return ret;
+
+	cache->cache_info_addr = CACHE_DEV_CACHE_INFO(cache->cache_dev);
+	cache->cache_ctrl = CACHE_DEV_CACHE_CTRL(cache->cache_dev);
+	backing_dev->cache = cache;
+	cache->dev_size = backing_dev->dev_size;
+
+	ret = cache_info_init(cache, opts);
+	if (ret)
+		goto cache_exit;
+
+	ret = cache_segs_init(cache);
+	if (ret)
+		goto cache_exit;
+
+	ret = cache_tail_init(cache);
+	if (ret)
+		goto cache_exit;
+
+	ret = cache_init_req_keys(cache, num_online_cpus());
+	if (ret)
+		goto cache_exit;
+
+	ret = cache_writeback_init(cache);
+	if (ret)
+		goto destroy_keys;
+
+	cache->cache_info.flags |= PCACHE_CACHE_FLAGS_INIT_DONE;
+	cache_info_write(cache);
+	queue_delayed_work(cache_get_wq(cache), &cache->gc_work, 0);
+
+	return 0;
+
+destroy_keys:
+	cache_destroy_req_keys(cache);
+cache_exit:
+	cache_exit(cache);
+
+	return ret;
+}
+
+void pcache_cache_stop(struct dm_pcache *pcache)
+{
+	struct pcache_cache *cache = &pcache->cache;
+
+	cache_flush(cache);
+
+	cancel_delayed_work_sync(&cache->gc_work);
+	flush_work(&cache->clean_work);
+	cache_writeback_exit(cache);
+
+	if (cache->req_key_tree.n_subtrees)
+		cache_destroy_req_keys(cache);
+
+	cache_exit(cache);
+}
+
+struct workqueue_struct *cache_get_wq(struct pcache_cache *cache)
+{
+	struct dm_pcache *pcache = CACHE_TO_PCACHE(cache);
+
+	return pcache->task_wq;
+}
+
+int pcache_cache_init(void)
+{
+	key_cache = KMEM_CACHE(pcache_cache_key, 0);
+	if (!key_cache)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void pcache_cache_exit(void)
+{
+	kmem_cache_destroy(key_cache);
+}