From 0349ff2887059112ce06831ab29aec47a2a7285a Mon Sep 17 00:00:00 2001 From: Pasha Tatashin Date: Wed, 3 Jun 2026 15:43:56 +0000 Subject: kho: add support for linked-block serialization Introduce a linked-block serialization mechanism for state handover. Previously, LUO used contiguous memory blocks for serializing sessions and files, which imposed limits on the total number of items that could be preserved across a live update. This commit adds the infrastructure for a more flexible, block-based approach where serialized data is stored in a chain of linked blocks. This is a generic KHO serialization block infrastructure that can be used by multiple subsystems. Signed-off-by: Pasha Tatashin Link: https://patch.msgid.link/20260603154402.468928-8-pasha.tatashin@soleen.com Signed-off-by: Mike Rapoport (Microsoft) --- include/linux/kho_block.h | 106 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) create mode 100644 include/linux/kho_block.h (limited to 'include/linux/kho_block.h') diff --git a/include/linux/kho_block.h b/include/linux/kho_block.h new file mode 100644 index 000000000000..93a7cc2be5f5 --- /dev/null +++ b/include/linux/kho_block.h @@ -0,0 +1,106 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (c) 2026, Google LLC. + * Pasha Tatashin + */ + +#ifndef _LINUX_KHO_BLOCK_H +#define _LINUX_KHO_BLOCK_H + +#include +#include +#include + +/** + * struct kho_block - Internal representation of a serialization block. + * @list: List head for linking blocks in memory. + * @ser: Pointer to the serialized header in preserved memory. + */ +struct kho_block { + struct list_head list; + struct kho_block_header_ser *ser; +}; + +/** + * struct kho_block_set - A set of blocks containing serialized entries of the same type. + * @blocks: The list of serialization blocks (struct kho_block). + * @nblocks: The number of allocated serialization blocks. + * @head_pa: Physical address of the first block header. + * @entry_size: The size of each entry in the blocks. + * @count_per_block: The maximum number of entries each block can hold. + * @incoming: True if this block set was restored from the previous kernel. + * + * Note: Synchronization and locking are the responsibility of the caller. + * The block set structure itself is not internally synchronized. + */ +struct kho_block_set { + struct list_head blocks; + long nblocks; + u64 head_pa; + size_t entry_size; + u64 count_per_block; + bool incoming; +}; + +/** + * struct kho_block_set_it - Iterator for serializing entries into blocks. + * @bs: The block set being iterated. + * @block: The current block. + * @i: The current entry index within @block. + */ +struct kho_block_set_it { + struct kho_block_set *bs; + struct kho_block *block; + u64 i; +}; + +/** + * KHO_BLOCK_SET_INIT - Initialize a static kho_block_set. + * @_name: Name of the kho_block_set variable. + * @_entry_size: The size of each entry in the block set. + */ +#define KHO_BLOCK_SET_INIT(_name, _entry_size) { \ + .blocks = LIST_HEAD_INIT((_name).blocks), \ + .entry_size = _entry_size, \ + .count_per_block = (KHO_BLOCK_SIZE - \ + sizeof(struct kho_block_header_ser)) / \ + (_entry_size), \ +} + +void kho_block_set_init(struct kho_block_set *bs, size_t entry_size); + +int kho_block_set_grow(struct kho_block_set *bs, u64 count); +void kho_block_set_shrink(struct kho_block_set *bs, u64 count); + +int kho_block_set_restore(struct kho_block_set *bs, u64 head_pa); +void kho_block_set_destroy(struct kho_block_set *bs); +void kho_block_set_clear(struct kho_block_set *bs); + +/** + * kho_block_set_head_pa - Get the physical address of the first block header. + * @bs: The block set. + * + * Return: The physical address of the first block header, or 0 if empty. + */ +static inline u64 kho_block_set_head_pa(struct kho_block_set *bs) +{ + return bs->head_pa; +} + +/** + * kho_block_set_is_empty - Check if the block set has no allocated blocks. + * @bs: The block set. + * + * Return: True if there are no blocks in the set, false otherwise. + */ +static inline bool kho_block_set_is_empty(struct kho_block_set *bs) +{ + return list_empty(&bs->blocks); +} + +void kho_block_set_it_init(struct kho_block_set_it *it, struct kho_block_set *bs); +void *kho_block_set_it_reserve_entry(struct kho_block_set_it *it); +void *kho_block_set_it_read_entry(struct kho_block_set_it *it); +void *kho_block_set_it_prev(struct kho_block_set_it *it); + +#endif /* _LINUX_KHO_BLOCK_H */ -- cgit v1.2.3