diff options
Diffstat (limited to 'kernel/bpf/hashtab.c')
| -rw-r--r-- | kernel/bpf/hashtab.c | 217 |
1 files changed, 212 insertions, 5 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index b32cc8ce8ff6..78dfff6a501b 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -1296,12 +1296,10 @@ static void htab_map_free(struct bpf_map *map) { struct bpf_htab *htab = container_of(map, struct bpf_htab, map); - /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, - * so the programs (can be more than one that used this map) were - * disconnected from events. Wait for outstanding critical sections in - * these programs to complete + /* bpf_free_used_maps() or close(map_fd) will trigger this map_free callback. + * bpf_free_used_maps() is called after bpf prog is no longer executing. + * There is no need to synchronize_rcu() here to protect map elements. */ - synchronize_rcu(); /* some of free_htab_elem() callbacks for elements of this map may * not have executed. Wait for them. @@ -1620,6 +1618,197 @@ htab_lru_map_lookup_and_delete_batch(struct bpf_map *map, true, false); } +struct bpf_iter_seq_hash_map_info { + struct bpf_map *map; + struct bpf_htab *htab; + void *percpu_value_buf; // non-zero means percpu hash + unsigned long flags; + u32 bucket_id; + u32 skip_elems; +}; + +static struct htab_elem * +bpf_hash_map_seq_find_next(struct bpf_iter_seq_hash_map_info *info, + struct htab_elem *prev_elem) +{ + const struct bpf_htab *htab = info->htab; + unsigned long flags = info->flags; + u32 skip_elems = info->skip_elems; + u32 bucket_id = info->bucket_id; + struct hlist_nulls_head *head; + struct hlist_nulls_node *n; + struct htab_elem *elem; + struct bucket *b; + u32 i, count; + + if (bucket_id >= htab->n_buckets) + return NULL; + + /* try to find next elem in the same bucket */ + if (prev_elem) { + /* no update/deletion on this bucket, prev_elem should be still valid + * and we won't skip elements. + */ + n = rcu_dereference_raw(hlist_nulls_next_rcu(&prev_elem->hash_node)); + elem = hlist_nulls_entry_safe(n, struct htab_elem, hash_node); + if (elem) + return elem; + + /* not found, unlock and go to the next bucket */ + b = &htab->buckets[bucket_id++]; + htab_unlock_bucket(htab, b, flags); + skip_elems = 0; + } + + for (i = bucket_id; i < htab->n_buckets; i++) { + b = &htab->buckets[i]; + flags = htab_lock_bucket(htab, b); + + count = 0; + head = &b->head; + hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) { + if (count >= skip_elems) { + info->flags = flags; + info->bucket_id = i; + info->skip_elems = count; + return elem; + } + count++; + } + + htab_unlock_bucket(htab, b, flags); + skip_elems = 0; + } + + info->bucket_id = i; + info->skip_elems = 0; + return NULL; +} + +static void *bpf_hash_map_seq_start(struct seq_file *seq, loff_t *pos) +{ + struct bpf_iter_seq_hash_map_info *info = seq->private; + struct htab_elem *elem; + + elem = bpf_hash_map_seq_find_next(info, NULL); + if (!elem) + return NULL; + + if (*pos == 0) + ++*pos; + return elem; +} + +static void *bpf_hash_map_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + struct bpf_iter_seq_hash_map_info *info = seq->private; + + ++*pos; + ++info->skip_elems; + return bpf_hash_map_seq_find_next(info, v); +} + +static int __bpf_hash_map_seq_show(struct seq_file *seq, struct htab_elem *elem) +{ + struct bpf_iter_seq_hash_map_info *info = seq->private; + u32 roundup_key_size, roundup_value_size; + struct bpf_iter__bpf_map_elem ctx = {}; + struct bpf_map *map = info->map; + struct bpf_iter_meta meta; + int ret = 0, off = 0, cpu; + struct bpf_prog *prog; + void __percpu *pptr; + + meta.seq = seq; + prog = bpf_iter_get_info(&meta, elem == NULL); + if (prog) { + ctx.meta = &meta; + ctx.map = info->map; + if (elem) { + roundup_key_size = round_up(map->key_size, 8); + ctx.key = elem->key; + if (!info->percpu_value_buf) { + ctx.value = elem->key + roundup_key_size; + } else { + roundup_value_size = round_up(map->value_size, 8); + pptr = htab_elem_get_ptr(elem, map->key_size); + for_each_possible_cpu(cpu) { + bpf_long_memcpy(info->percpu_value_buf + off, + per_cpu_ptr(pptr, cpu), + roundup_value_size); + off += roundup_value_size; + } + ctx.value = info->percpu_value_buf; + } + } + ret = bpf_iter_run_prog(prog, &ctx); + } + + return ret; +} + +static int bpf_hash_map_seq_show(struct seq_file *seq, void *v) +{ + return __bpf_hash_map_seq_show(seq, v); +} + +static void bpf_hash_map_seq_stop(struct seq_file *seq, void *v) +{ + struct bpf_iter_seq_hash_map_info *info = seq->private; + + if (!v) + (void)__bpf_hash_map_seq_show(seq, NULL); + else + htab_unlock_bucket(info->htab, + &info->htab->buckets[info->bucket_id], + info->flags); +} + +static int bpf_iter_init_hash_map(void *priv_data, + struct bpf_iter_aux_info *aux) +{ + struct bpf_iter_seq_hash_map_info *seq_info = priv_data; + struct bpf_map *map = aux->map; + void *value_buf; + u32 buf_size; + + if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) { + buf_size = round_up(map->value_size, 8) * num_possible_cpus(); + value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN); + if (!value_buf) + return -ENOMEM; + + seq_info->percpu_value_buf = value_buf; + } + + seq_info->map = map; + seq_info->htab = container_of(map, struct bpf_htab, map); + return 0; +} + +static void bpf_iter_fini_hash_map(void *priv_data) +{ + struct bpf_iter_seq_hash_map_info *seq_info = priv_data; + + kfree(seq_info->percpu_value_buf); +} + +static const struct seq_operations bpf_hash_map_seq_ops = { + .start = bpf_hash_map_seq_start, + .next = bpf_hash_map_seq_next, + .stop = bpf_hash_map_seq_stop, + .show = bpf_hash_map_seq_show, +}; + +static const struct bpf_iter_seq_info iter_seq_info = { + .seq_ops = &bpf_hash_map_seq_ops, + .init_seq_private = bpf_iter_init_hash_map, + .fini_seq_private = bpf_iter_fini_hash_map, + .seq_priv_size = sizeof(struct bpf_iter_seq_hash_map_info), +}; + +static int htab_map_btf_id; const struct bpf_map_ops htab_map_ops = { .map_alloc_check = htab_map_alloc_check, .map_alloc = htab_map_alloc, @@ -1631,8 +1820,12 @@ const struct bpf_map_ops htab_map_ops = { .map_gen_lookup = htab_map_gen_lookup, .map_seq_show_elem = htab_map_seq_show_elem, BATCH_OPS(htab), + .map_btf_name = "bpf_htab", + .map_btf_id = &htab_map_btf_id, + .iter_seq_info = &iter_seq_info, }; +static int htab_lru_map_btf_id; const struct bpf_map_ops htab_lru_map_ops = { .map_alloc_check = htab_map_alloc_check, .map_alloc = htab_map_alloc, @@ -1645,6 +1838,9 @@ const struct bpf_map_ops htab_lru_map_ops = { .map_gen_lookup = htab_lru_map_gen_lookup, .map_seq_show_elem = htab_map_seq_show_elem, BATCH_OPS(htab_lru), + .map_btf_name = "bpf_htab", + .map_btf_id = &htab_lru_map_btf_id, + .iter_seq_info = &iter_seq_info, }; /* Called from eBPF program */ @@ -1749,6 +1945,7 @@ static void htab_percpu_map_seq_show_elem(struct bpf_map *map, void *key, rcu_read_unlock(); } +static int htab_percpu_map_btf_id; const struct bpf_map_ops htab_percpu_map_ops = { .map_alloc_check = htab_map_alloc_check, .map_alloc = htab_map_alloc, @@ -1759,8 +1956,12 @@ const struct bpf_map_ops htab_percpu_map_ops = { .map_delete_elem = htab_map_delete_elem, .map_seq_show_elem = htab_percpu_map_seq_show_elem, BATCH_OPS(htab_percpu), + .map_btf_name = "bpf_htab", + .map_btf_id = &htab_percpu_map_btf_id, + .iter_seq_info = &iter_seq_info, }; +static int htab_lru_percpu_map_btf_id; const struct bpf_map_ops htab_lru_percpu_map_ops = { .map_alloc_check = htab_map_alloc_check, .map_alloc = htab_map_alloc, @@ -1771,6 +1972,9 @@ const struct bpf_map_ops htab_lru_percpu_map_ops = { .map_delete_elem = htab_lru_map_delete_elem, .map_seq_show_elem = htab_percpu_map_seq_show_elem, BATCH_OPS(htab_lru_percpu), + .map_btf_name = "bpf_htab", + .map_btf_id = &htab_lru_percpu_map_btf_id, + .iter_seq_info = &iter_seq_info, }; static int fd_htab_map_alloc_check(union bpf_attr *attr) @@ -1893,6 +2097,7 @@ static void htab_of_map_free(struct bpf_map *map) fd_htab_map_free(map); } +static int htab_of_maps_map_btf_id; const struct bpf_map_ops htab_of_maps_map_ops = { .map_alloc_check = fd_htab_map_alloc_check, .map_alloc = htab_of_map_alloc, @@ -1905,4 +2110,6 @@ const struct bpf_map_ops htab_of_maps_map_ops = { .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem, .map_gen_lookup = htab_of_map_gen_lookup, .map_check_btf = map_check_no_btf, + .map_btf_name = "bpf_htab", + .map_btf_id = &htab_of_maps_map_btf_id, }; |