101 lines
2.1 KiB
C
101 lines
2.1 KiB
C
/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
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/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
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#pragma once
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#include <errno.h>
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#include "bpf_arena_alloc.h"
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#include "bpf_arena_list.h"
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struct htab_bucket {
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struct arena_list_head head;
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};
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typedef struct htab_bucket __arena htab_bucket_t;
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struct htab {
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htab_bucket_t *buckets;
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int n_buckets;
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};
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typedef struct htab __arena htab_t;
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static inline htab_bucket_t *__select_bucket(htab_t *htab, __u32 hash)
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{
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htab_bucket_t *b = htab->buckets;
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cast_kern(b);
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return &b[hash & (htab->n_buckets - 1)];
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}
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static inline arena_list_head_t *select_bucket(htab_t *htab, __u32 hash)
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{
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return &__select_bucket(htab, hash)->head;
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}
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struct hashtab_elem {
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int hash;
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int key;
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int value;
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struct arena_list_node hash_node;
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};
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typedef struct hashtab_elem __arena hashtab_elem_t;
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static hashtab_elem_t *lookup_elem_raw(arena_list_head_t *head, __u32 hash, int key)
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{
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hashtab_elem_t *l;
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list_for_each_entry(l, head, hash_node)
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if (l->hash == hash && l->key == key)
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return l;
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return NULL;
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}
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static int htab_hash(int key)
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{
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return key;
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}
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__weak int htab_lookup_elem(htab_t *htab __arg_arena, int key)
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{
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hashtab_elem_t *l_old;
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arena_list_head_t *head;
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cast_kern(htab);
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head = select_bucket(htab, key);
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l_old = lookup_elem_raw(head, htab_hash(key), key);
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if (l_old)
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return l_old->value;
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return 0;
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}
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__weak int htab_update_elem(htab_t *htab __arg_arena, int key, int value)
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{
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hashtab_elem_t *l_new = NULL, *l_old;
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arena_list_head_t *head;
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cast_kern(htab);
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head = select_bucket(htab, key);
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l_old = lookup_elem_raw(head, htab_hash(key), key);
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l_new = bpf_alloc(sizeof(*l_new));
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if (!l_new)
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return -ENOMEM;
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l_new->key = key;
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l_new->hash = htab_hash(key);
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l_new->value = value;
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list_add_head(&l_new->hash_node, head);
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if (l_old) {
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list_del(&l_old->hash_node);
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bpf_free(l_old);
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}
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return 0;
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}
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void htab_init(htab_t *htab)
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{
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void __arena *buckets = bpf_arena_alloc_pages(&arena, NULL, 2, NUMA_NO_NODE, 0);
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cast_user(buckets);
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htab->buckets = buckets;
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htab->n_buckets = 2 * PAGE_SIZE / sizeof(struct htab_bucket);
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}
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