Commit b76f2226 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

bpf: Implement link_query callbacks in map element iterators 



For bpf_map_elem and bpf_sk_local_storage bpf iterators,
additional map_id should be shown for fdinfo and
userspace query. For example, the following is for
a bpf_map_elem iterator.
  $ cat /proc/1753/fdinfo/9
  pos:    0
  flags:  02000000
  mnt_id: 14
  link_type:      iter
  link_id:        34
  prog_tag:       104be6d3fe45e6aa
  prog_id:        173
  target_name:    bpf_map_elem
  map_id: 127

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200821184419.574240-1-yhs@fb.com
parent 6b0a249a

include/linux/bpf.h

+4 −0
Original line number Diff line number Diff line
@@ -1256,6 +1256,10 @@ int bpf_iter_new_fd(struct bpf_link *link); 
bool bpf_link_is_iter(struct bpf_link *link);

struct bpf_prog *bpf_iter_get_info(struct bpf_iter_meta *meta, bool in_stop);

int bpf_iter_run_prog(struct bpf_prog *prog, void *ctx);

void bpf_iter_map_show_fdinfo(const struct bpf_iter_aux_info *aux,

			      struct seq_file *seq);

int bpf_iter_map_fill_link_info(const struct bpf_iter_aux_info *aux,

				struct bpf_link_info *info);



int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);

int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);

kernel/bpf/map_iter.c

+15 −0
Original line number Diff line number Diff line
@@ -149,6 +149,19 @@ static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux) 
	bpf_map_put_with_uref(aux->map);

}



void bpf_iter_map_show_fdinfo(const struct bpf_iter_aux_info *aux,

			      struct seq_file *seq)

{

	seq_printf(seq, "map_id:\t%u\n", aux->map->id);

}



int bpf_iter_map_fill_link_info(const struct bpf_iter_aux_info *aux,

				struct bpf_link_info *info)

{

	info->iter.map.map_id = aux->map->id;

	return 0;

}



DEFINE_BPF_ITER_FUNC(bpf_map_elem, struct bpf_iter_meta *meta,

		     struct bpf_map *map, void *key, void *value)
@@ -156,6 +169,8 @@ static const struct bpf_iter_reg bpf_map_elem_reg_info = { 
	.target			= "bpf_map_elem",

	.attach_target		= bpf_iter_attach_map,

	.detach_target		= bpf_iter_detach_map,

	.show_fdinfo		= bpf_iter_map_show_fdinfo,

	.fill_link_info		= bpf_iter_map_fill_link_info,

	.ctx_arg_info_size	= 2,

	.ctx_arg_info		= {

		{ offsetof(struct bpf_iter__bpf_map_elem, key),

net/core/bpf_sk_storage.c

+2 −0
Original line number Diff line number Diff line
@@ -1437,6 +1437,8 @@ static struct bpf_iter_reg bpf_sk_storage_map_reg_info = { 
	.target			= "bpf_sk_storage_map",

	.attach_target		= bpf_iter_attach_map,

	.detach_target		= bpf_iter_detach_map,

	.show_fdinfo		= bpf_iter_map_show_fdinfo,

	.fill_link_info		= bpf_iter_map_fill_link_info,

	.ctx_arg_info_size	= 2,

	.ctx_arg_info		= {

		{ offsetof(struct bpf_iter__bpf_sk_storage_map, sk),

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