diff options
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 77 |
1 files changed, 42 insertions, 35 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 9b55006593c0..b01fe01b0761 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2331,6 +2331,37 @@ int parse_btf_map_def(const char *map_name, struct btf *btf, return 0; } +static size_t adjust_ringbuf_sz(size_t sz) +{ + __u32 page_sz = sysconf(_SC_PAGE_SIZE); + __u32 mul; + + /* if user forgot to set any size, make sure they see error */ + if (sz == 0) + return 0; + /* Kernel expects BPF_MAP_TYPE_RINGBUF's max_entries to be + * a power-of-2 multiple of kernel's page size. If user diligently + * satisified these conditions, pass the size through. + */ + if ((sz % page_sz) == 0 && is_pow_of_2(sz / page_sz)) + return sz; + + /* Otherwise find closest (page_sz * power_of_2) product bigger than + * user-set size to satisfy both user size request and kernel + * requirements and substitute correct max_entries for map creation. + */ + for (mul = 1; mul <= UINT_MAX / page_sz; mul <<= 1) { + if (mul * page_sz > sz) + return mul * page_sz; + } + + /* if it's impossible to satisfy the conditions (i.e., user size is + * very close to UINT_MAX but is not a power-of-2 multiple of + * page_size) then just return original size and let kernel reject it + */ + return sz; +} + static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def) { map->def.type = def->map_type; @@ -2344,6 +2375,10 @@ static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def map->btf_key_type_id = def->key_type_id; map->btf_value_type_id = def->value_type_id; + /* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */ + if (map->def.type == BPF_MAP_TYPE_RINGBUF) + map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries); + if (def->parts & MAP_DEF_MAP_TYPE) pr_debug("map '%s': found type = %u.\n", map->name, def->map_type); @@ -4317,9 +4352,15 @@ struct bpf_map *bpf_map__inner_map(struct bpf_map *map) int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries) { - if (map->fd >= 0) + if (map->obj->loaded) return libbpf_err(-EBUSY); + map->def.max_entries = max_entries; + + /* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */ + if (map->def.type == BPF_MAP_TYPE_RINGBUF) + map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries); + return 0; } @@ -4875,37 +4916,6 @@ bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map) static void bpf_map__destroy(struct bpf_map *map); -static size_t adjust_ringbuf_sz(size_t sz) -{ - __u32 page_sz = sysconf(_SC_PAGE_SIZE); - __u32 mul; - - /* if user forgot to set any size, make sure they see error */ - if (sz == 0) - return 0; - /* Kernel expects BPF_MAP_TYPE_RINGBUF's max_entries to be - * a power-of-2 multiple of kernel's page size. If user diligently - * satisified these conditions, pass the size through. - */ - if ((sz % page_sz) == 0 && is_pow_of_2(sz / page_sz)) - return sz; - - /* Otherwise find closest (page_sz * power_of_2) product bigger than - * user-set size to satisfy both user size request and kernel - * requirements and substitute correct max_entries for map creation. - */ - for (mul = 1; mul <= UINT_MAX / page_sz; mul <<= 1) { - if (mul * page_sz > sz) - return mul * page_sz; - } - - /* if it's impossible to satisfy the conditions (i.e., user size is - * very close to UINT_MAX but is not a power-of-2 multiple of - * page_size) then just return original size and let kernel reject it - */ - return sz; -} - static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, bool is_inner) { LIBBPF_OPTS(bpf_map_create_opts, create_attr); @@ -4944,9 +4954,6 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b } switch (def->type) { - case BPF_MAP_TYPE_RINGBUF: - map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries); - /* fallthrough */ case BPF_MAP_TYPE_PERF_EVENT_ARRAY: case BPF_MAP_TYPE_CGROUP_ARRAY: case BPF_MAP_TYPE_STACK_TRACE: |