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| author | Martin KaFai Lau <kafai@fb.com> | 2017-06-27 23:08:34 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-06-29 13:13:25 -0400 |
| commit | 14dc6f04f49dc12614d7e90928b495b8d73cd471 (patch) | |
| tree | 159ebddef04be2ae417c503ab46593be570c680f /kernel/bpf/hashtab.c | |
| parent | 77b0d3617738e532bae683bf9d88ea35fff223e5 (diff) | |
| download | linux-14dc6f04f49dc12614d7e90928b495b8d73cd471.tar.bz2 | |
bpf: Add syscall lookup support for fd array and htab
This patch allows userspace to do BPF_MAP_LOOKUP_ELEM on
BPF_MAP_TYPE_PROG_ARRAY,
BPF_MAP_TYPE_ARRAY_OF_MAPS and
BPF_MAP_TYPE_HASH_OF_MAPS.
The lookup returns a prog-id or map-id to the userspace.
The userspace can then use the BPF_PROG_GET_FD_BY_ID
or BPF_MAP_GET_FD_BY_ID to get a fd.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/bpf/hashtab.c')
| -rw-r--r-- | kernel/bpf/hashtab.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 004334ea13ba..4fb463172aa8 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -1244,6 +1244,26 @@ static void fd_htab_map_free(struct bpf_map *map) } /* only called from syscall */ +int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value) +{ + void **ptr; + int ret = 0; + + if (!map->ops->map_fd_sys_lookup_elem) + return -ENOTSUPP; + + rcu_read_lock(); + ptr = htab_map_lookup_elem(map, key); + if (ptr) + *value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr)); + else + ret = -ENOENT; + rcu_read_unlock(); + + return ret; +} + +/* only called from syscall */ int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file, void *key, void *value, u64 map_flags) { @@ -1305,4 +1325,5 @@ const struct bpf_map_ops htab_of_maps_map_ops = { .map_delete_elem = htab_map_delete_elem, .map_fd_get_ptr = bpf_map_fd_get_ptr, .map_fd_put_ptr = bpf_map_fd_put_ptr, + .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem, }; |