diff options
Diffstat (limited to 'drivers/md/dm-pcache/cache.c')
| -rw-r--r-- | drivers/md/dm-pcache/cache.c | 445 |
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); +} |