Messages in this thread Patch in this message | | | From | Roman Gushchin <> | Subject | [PATCH bpf-next 2/3] bpf: add bpffs pretty print for cgroup local storage maps | Date | Fri, 7 Dec 2018 16:53:14 -0800 |
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Implement bpffs pretty printing for cgroup local storage maps (both shared and per-cpu). Output example (captured for tools/testing/selftests/bpf/netcnt_prog.c):
Shared: $ cat /sys/fs/bpf/map_2 # WARNING!! The output is for debug purpose only # WARNING!! The output format will change {4294968594,1}: {9999,1039896}
Per-cpu: $ cat /sys/fs/bpf/map_1 # WARNING!! The output is for debug purpose only # WARNING!! The output format will change {4294968594,1}: { cpu0: {0,0,0,0,0} cpu1: {0,0,0,0,0} cpu2: {1,104,0,0,0} cpu3: {0,0,0,0,0} }
Signed-off-by: Roman Gushchin <guro@fb.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> --- include/linux/btf.h | 10 +++++ kernel/bpf/local_storage.c | 90 +++++++++++++++++++++++++++++++++++++- 2 files changed, 99 insertions(+), 1 deletion(-)
diff --git a/include/linux/btf.h b/include/linux/btf.h index 8c2199b5d250..ac67bc4cbfd9 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -5,6 +5,7 @@ #define _LINUX_BTF_H 1 #include <linux/types.h> +#include <uapi/linux/btf.h> struct btf; struct btf_type; @@ -63,4 +64,13 @@ static inline const char *btf_name_by_offset(const struct btf *btf, } #endif +static inline const struct btf_type *btf_orig_type(const struct btf *btf, + const struct btf_type *t) +{ + while (t && BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) + t = btf_type_by_id(btf, t->type); + + return t; +} + #endif diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c index b65017dead44..7b51fe1aba3c 100644 --- a/kernel/bpf/local_storage.c +++ b/kernel/bpf/local_storage.c @@ -1,11 +1,13 @@ //SPDX-License-Identifier: GPL-2.0 #include <linux/bpf-cgroup.h> #include <linux/bpf.h> +#include <linux/btf.h> #include <linux/bug.h> #include <linux/filter.h> #include <linux/mm.h> #include <linux/rbtree.h> #include <linux/slab.h> +#include <uapi/linux/btf.h> DEFINE_PER_CPU(struct bpf_cgroup_storage*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]); @@ -308,6 +310,91 @@ static int cgroup_storage_delete_elem(struct bpf_map *map, void *key) return -EINVAL; } +static int cgroup_storage_check_btf(const struct bpf_map *map, + const struct btf *btf, + const struct btf_type *key_type, + const struct btf_type *value_type) +{ + const struct btf_type *st, *t; + struct btf_member *m; + + /* Key is expected to be of struct bpf_cgroup_storage_key type, + * which is: + * struct bpf_cgroup_storage_key { + * __u64 cgroup_inode_id; + * __u32 attach_type; + * }; + */ + + /* + * Key_type must be a structure (or a typedef of a structure) with + * two members. + */ + st = btf_orig_type(btf, key_type); + if (BTF_INFO_KIND(st->info) != BTF_KIND_STRUCT || + BTF_INFO_VLEN(st->info) != 2) + return -EINVAL; + + /* + * The first field must be a 64 bit integer at 0 offset. + */ + m = (struct btf_member *)(st + 1); + t = btf_orig_type(btf, btf_type_by_id(btf, m->type)); + if (!t || BTF_INFO_KIND(t->info) != BTF_KIND_INT || m->offset || + t->size != + FIELD_SIZEOF(struct bpf_cgroup_storage_key, cgroup_inode_id)) + return -EINVAL; + + /* + * The second field must be a 32 bit integer at 0 offset. + */ + m = m + 1; + t = btf_orig_type(btf, btf_type_by_id(btf, m->type)); + if (!t || BTF_INFO_KIND(t->info) != BTF_KIND_INT || + m->offset != offsetof(struct bpf_cgroup_storage_key, attach_type) * + BITS_PER_BYTE || t->size != + FIELD_SIZEOF(struct bpf_cgroup_storage_key, attach_type)) + return -EINVAL; + + return 0; +} + +static void cgroup_storage_seq_show_elem(struct bpf_map *map, void *_key, + struct seq_file *m) +{ + enum bpf_cgroup_storage_type stype = cgroup_storage_type(map); + struct bpf_cgroup_storage_key *key = _key; + struct bpf_cgroup_storage *storage; + int cpu; + + rcu_read_lock(); + storage = cgroup_storage_lookup(map_to_storage(map), key, false); + if (!storage) { + rcu_read_unlock(); + return; + } + + btf_type_seq_show(map->btf, map->btf_key_type_id, key, m); + stype = cgroup_storage_type(map); + if (stype == BPF_CGROUP_STORAGE_SHARED) { + seq_puts(m, ": "); + btf_type_seq_show(map->btf, map->btf_value_type_id, + &READ_ONCE(storage->buf)->data[0], m); + seq_puts(m, "\n"); + } else { + seq_puts(m, ": {\n"); + for_each_possible_cpu(cpu) { + seq_printf(m, "\tcpu%d: ", cpu); + btf_type_seq_show(map->btf, map->btf_value_type_id, + per_cpu_ptr(storage->percpu_buf, cpu), + m); + seq_puts(m, "\n"); + } + seq_puts(m, "}\n"); + } + rcu_read_unlock(); +} + const struct bpf_map_ops cgroup_storage_map_ops = { .map_alloc = cgroup_storage_map_alloc, .map_free = cgroup_storage_map_free, @@ -315,7 +402,8 @@ const struct bpf_map_ops cgroup_storage_map_ops = { .map_lookup_elem = cgroup_storage_lookup_elem, .map_update_elem = cgroup_storage_update_elem, .map_delete_elem = cgroup_storage_delete_elem, - .map_check_btf = map_check_no_btf, + .map_check_btf = cgroup_storage_check_btf, + .map_seq_show_elem = cgroup_storage_seq_show_elem, }; int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map) -- 2.19.2
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