linux/include/linux/bpf_local_storage.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (c) 2019 Facebook
 * Copyright 2020 Google LLC.
 */

#ifndef _BPF_LOCAL_STORAGE_H
#define _BPF_LOCAL_STORAGE_H

#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/rculist.h>
#include <linux/list.h>
#include <linux/hash.h>
#include <linux/types.h>
#include <linux/bpf_mem_alloc.h>
#include <uapi/linux/btf.h>

#define BPF_LOCAL_STORAGE_CACHE_SIZE …

#define bpf_rcu_lock_held() …
struct bpf_local_storage_map_bucket { … };

/* Thp map is not the primary owner of a bpf_local_storage_elem.
 * Instead, the container object (eg. sk->sk_bpf_storage) is.
 *
 * The map (bpf_local_storage_map) is for two purposes
 * 1. Define the size of the "local storage".  It is
 *    the map's value_size.
 *
 * 2. Maintain a list to keep track of all elems such
 *    that they can be cleaned up during the map destruction.
 *
 * When a bpf local storage is being looked up for a
 * particular object,  the "bpf_map" pointer is actually used
 * as the "key" to search in the list of elem in
 * the respective bpf_local_storage owned by the object.
 *
 * e.g. sk->sk_bpf_storage is the mini-map with the "bpf_map" pointer
 * as the searching key.
 */
struct bpf_local_storage_map { … };

struct bpf_local_storage_data { … };

/* Linked to bpf_local_storage and bpf_local_storage_map */
struct bpf_local_storage_elem { … };

struct bpf_local_storage { … };

/* U16_MAX is much more than enough for sk local storage
 * considering a tcp_sock is ~2k.
 */
#define BPF_LOCAL_STORAGE_MAX_VALUE_SIZE …

#define SELEM(_SDATA) …
#define SDATA(_SELEM) …

#define BPF_LOCAL_STORAGE_CACHE_SIZE …

struct bpf_local_storage_cache { … };

#define DEFINE_BPF_STORAGE_CACHE(name) …

/* Helper functions for bpf_local_storage */
int bpf_local_storage_map_alloc_check(union bpf_attr *attr);

struct bpf_map *
bpf_local_storage_map_alloc(union bpf_attr *attr,
			    struct bpf_local_storage_cache *cache,
			    bool bpf_ma);

void __bpf_local_storage_insert_cache(struct bpf_local_storage *local_storage,
				      struct bpf_local_storage_map *smap,
				      struct bpf_local_storage_elem *selem);
/* If cacheit_lockit is false, this lookup function is lockless */
static inline struct bpf_local_storage_data *
bpf_local_storage_lookup(struct bpf_local_storage *local_storage,
			 struct bpf_local_storage_map *smap,
			 bool cacheit_lockit)
{ … }

void bpf_local_storage_destroy(struct bpf_local_storage *local_storage);

void bpf_local_storage_map_free(struct bpf_map *map,
				struct bpf_local_storage_cache *cache,
				int __percpu *busy_counter);

int bpf_local_storage_map_check_btf(const struct bpf_map *map,
				    const struct btf *btf,
				    const struct btf_type *key_type,
				    const struct btf_type *value_type);

void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage,
				   struct bpf_local_storage_elem *selem);

void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now);

void bpf_selem_link_map(struct bpf_local_storage_map *smap,
			struct bpf_local_storage_elem *selem);

struct bpf_local_storage_elem *
bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, void *value,
		bool charge_mem, gfp_t gfp_flags);

void bpf_selem_free(struct bpf_local_storage_elem *selem,
		    struct bpf_local_storage_map *smap,
		    bool reuse_now);

int
bpf_local_storage_alloc(void *owner,
			struct bpf_local_storage_map *smap,
			struct bpf_local_storage_elem *first_selem,
			gfp_t gfp_flags);

struct bpf_local_storage_data *
bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap,
			 void *value, u64 map_flags, gfp_t gfp_flags);

u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map);

#endif /* _BPF_LOCAL_STORAGE_H */