On 3/21/23 10:49, Martin KaFai Lau wrote:
On 3/20/23 12:56 PM, Kui-Feng Lee wrote:struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map) { - struct bpf_struct_ops *st_ops; - struct bpf_link *link; - __u32 i, zero = 0; - int err; + struct bpf_link_struct_ops *link; + __u32 zero = 0; + int err, fd; if (!bpf_map__is_struct_ops(map) || map->fd == -1) return libbpf_err_ptr(-EINVAL);@@ -11596,31 +11637,32 @@ struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map)if (!link) return libbpf_err_ptr(-EINVAL); - st_ops = map->st_ops; - for (i = 0; i < btf_vlen(st_ops->type); i++) { - struct bpf_program *prog = st_ops->progs[i]; - void *kern_data; - int prog_fd; + /* kern_vdata should be prepared during the loading phase. */+ err = bpf_map_update_elem(map->fd, &zero, map->st_ops->kern_vdata, 0);+ if (err && err != -EBUSY) { + free(link); + return libbpf_err_ptr(err); + } - if (!prog) - continue; + link->link.detach = bpf_link__detach_struct_ops; - prog_fd = bpf_program__fd(prog); - kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i]; - *(unsigned long *)kern_data = prog_fd; + if (!(map->def.map_flags & BPF_F_LINK)) {hmm... This still does not look right. 'err' could be -EBUSY here and should not be treated as success for non BPF_F_LINK case. The above 'err && err != -EBUSY' check should also consider the BPF_F_LINK map_flags.
Ouch! Will fixed it.
[ Replied on the wrong v9, so copy-and-paste the reply back to this v9. ]+ /* w/o a real link */ + link->link.fd = map->fd; + link->map_fd = -1; + return &link->link; } - err = bpf_map_update_elem(map->fd, &zero, st_ops->kern_vdata, 0); - if (err) { - err = -errno; + fd = bpf_link_create(map->fd, 0, BPF_STRUCT_OPS, NULL); + if (fd < 0) { free(link); - return libbpf_err_ptr(err); + return libbpf_err_ptr(fd); } - link->detach = bpf_link__detach_struct_ops; - link->fd = map->fd; + link->link.fd = fd; + link->map_fd = map->fd; - return link; + return &link->link; }typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(struct perf_event_header *hdr,
