1 /* SPDX-License-Identifier: GPL-2.0-or-later */
5 #include "segment.h"
38 /* Offset and size definitions for cache segment control */
79 	u32			cache_seg_id;   /* Index in cache->segments */
80 	struct pcache_segment	segment;  member
225 	return FIELD_GET(PCACHE_CACHE_FLAGS_GC_PERCENT_MASK, cache->cache_info.flags);  in pcache_cache_get_gc_percent()
268 	/* pre-allocated key and backing_dev_req */
276 	 *	  |--------|		key_tmp
283 	 * |----------|			key_tmp
290 	 *     |----------------|	key_tmp
297 	 * |--------|			key_tmp
304 	 *    |----|			key_tmp
311 	 * |-----------|		key_tmp
357 	if (cache_tree->n_subtrees == 1)  in get_subtree()
358 		return &cache_tree->subtrees[0];  in get_subtree()
360 	return &cache_tree->subtrees[off >> PCACHE_CACHE_SUBTREE_SIZE_SHIFT];  in get_subtree()
365 	return (pos->cache_seg->segment.data + pos->seg_off);  in cache_pos_addr()
370 	return cache_pos_addr(&cache->key_head);  in get_key_head_addr()
377 	div_u64_rem(off >> PCACHE_CACHE_SUBTREE_SIZE_SHIFT, cache->n_ksets, &kset_id);  in get_kset_id()
384 	return (void *)cache->ksets + PCACHE_KSET_SIZE * kset_id;  in get_kset()
389 	return this_cpu_ptr(cache->data_heads);  in get_data_head()
394 	return key->flags & PCACHE_CACHE_KEY_FLAGS_EMPTY;  in cache_key_empty()
399 	return key->flags & PCACHE_CACHE_KEY_FLAGS_CLEAN;  in cache_key_clean()
408  * cache_seg_is_ctrl_seg - Checks if a cache segment is a cache ctrl segment.
409  * @cache_seg_id: ID of the cache segment.
411  * Returns true if the cache segment ID corresponds to a cache ctrl segment.
413  * Note: We extend the segment control of the first cache segment
414  * (cache segment ID 0) to serve as the cache control (pcache_cache_ctrl)
416  * cache segment is the one storing the pcache_cache_ctrl information.
424  * cache_key_cutfront - Cuts a specified length from the front of a cache key.
432 	if (key->cache_pos.cache_seg)  in cache_key_cutfront()
433 		cache_pos_advance(&key->cache_pos, cut_len);  in cache_key_cutfront()
435 	key->off += cut_len;  in cache_key_cutfront()
436 	key->len -= cut_len;  in cache_key_cutfront()
440  * cache_key_cutback - Cuts a specified length from the back of a cache key.
448 	key->len -= cut_len;  in cache_key_cutback()
455 	cache_subtree = key->cache_subtree;  in cache_key_delete()
458 	rb_erase(&key->rb_node, &cache_subtree->root);  in cache_key_delete()
459 	key->flags = 0;  in cache_key_delete()
465 	return (cache->cache_info.flags & PCACHE_CACHE_FLAGS_DATA_CRC);  in cache_data_crc_on()
470 	return FIELD_GET(PCACHE_CACHE_FLAGS_CACHE_MODE_MASK, cache->cache_info.flags);  in cache_mode_get()
475 	cache->cache_info.flags &= ~PCACHE_CACHE_FLAGS_CACHE_MODE_MASK;  in cache_mode_set()
476 	cache->cache_info.flags |= FIELD_PREP(PCACHE_CACHE_FLAGS_CACHE_MODE_MASK, cache_mode);  in cache_mode_set()
480  * cache_key_data_crc - Calculates CRC for data in a cache key.
483  * Returns the CRC-32 checksum of the data within the cache key's position.
489 	data = cache_pos_addr(&key->cache_pos);  in cache_key_data_crc()
491 	return crc32c(PCACHE_CRC_SEED, data, key->len);  in cache_key_data_crc()
498 	if (kset_onmedia->flags & PCACHE_KSET_FLAGS_LAST)  in cache_kset_crc()
499 		crc_size = sizeof(struct pcache_cache_kset_onmedia) - 4;  in cache_kset_crc()
501 		crc_size = struct_size(kset_onmedia, data, kset_onmedia->key_num) - 4;  in cache_kset_crc()
508 	return struct_size_t(struct pcache_cache_kset_onmedia, data, kset_onmedia->key_num);  in get_kset_onmedia_size()
512  * cache_seg_remain - Computes remaining space in a cache segment.
515  * Returns the amount of remaining space in the segment data starting from
521 	struct pcache_segment *segment;  in cache_seg_remain()  local
524 	cache_seg = pos->cache_seg;  in cache_seg_remain()
525 	segment = &cache_seg->segment;  in cache_seg_remain()
526 	seg_remain = segment->data_size - pos->seg_off;  in cache_seg_remain()
532  * cache_key_invalid - Checks if a cache key is invalid.
536  * less than the generation of its segment; otherwise returns false.
538  * When the GC (garbage collection) thread identifies a segment
539  * as reclaimable, it increments the segment's generation (gen). However,
549 	return (key->seg_gen < key->cache_pos.cache_seg->gen);  in cache_key_invalid()
553  * cache_key_lstart - Retrieves the logical start offset of a cache key.
560 	return key->off;  in cache_key_lstart()
564  * cache_key_lend - Retrieves the logical end offset of a cache key.
571 	return key->off + key->len;  in cache_key_lend()
576 	key_dst->off = key_src->off;  in cache_key_copy()
577 	key_dst->len = key_src->len;  in cache_key_copy()
578 	key_dst->seg_gen = key_src->seg_gen;  in cache_key_copy()
579 	key_dst->cache_tree = key_src->cache_tree;  in cache_key_copy()
580 	key_dst->cache_subtree = key_src->cache_subtree;  in cache_key_copy()
581 	key_dst->flags = key_src->flags;  in cache_key_copy()
583 	cache_pos_copy(&key_dst->cache_pos, &key_src->cache_pos);  in cache_key_copy()
587  * cache_pos_onmedia_crc - Calculates the CRC for an on-media cache position.
590  * Calculates the CRC-32 checksum of the position, excluding the first 4 bytes.
595 	return pcache_meta_crc(&pos_om->header, sizeof(struct pcache_cache_pos_onmedia));  in cache_pos_onmedia_crc()
607 	cache_pos_encode(cache, cache->cache_ctrl->key_tail_pos,  in cache_encode_key_tail()
608 			&cache->key_tail, ++cache->key_tail_seq,  in cache_encode_key_tail()
609 			&cache->key_tail_index);  in cache_encode_key_tail()
614 	return cache_pos_decode(cache, cache->cache_ctrl->key_tail_pos,  in cache_decode_key_tail()
615 				&cache->key_tail, &cache->key_tail_seq,  in cache_decode_key_tail()
616 				&cache->key_tail_index);  in cache_decode_key_tail()
621 	cache_pos_encode(cache, cache->cache_ctrl->dirty_tail_pos,  in cache_encode_dirty_tail()
622 			&cache->dirty_tail, ++cache->dirty_tail_seq,  in cache_encode_dirty_tail()
623 			&cache->dirty_tail_index);  in cache_encode_dirty_tail()
628 	return cache_pos_decode(cache, cache->cache_ctrl->dirty_tail_pos,  in cache_decode_dirty_tail()
629 				&cache->dirty_tail, &cache->dirty_tail_seq,  in cache_decode_dirty_tail()
630 				&cache->dirty_tail_index);  in cache_decode_dirty_tail()