diff options
| author | Andrii Nakryiko <andriin@fb.com> | 2020-04-28 17:16:06 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-04-28 17:27:08 -0700 |
| commit | a3b80e1078943dc12553166fb08e258463dec013 (patch) | |
| tree | e022212949f8028eacf0c5d3ad77218d7f1a7b1a /kernel/bpf/cgroup.c | |
| parent | f9d041271cf44ca02eed0cc82e1a6d8c814c53ed (diff) | |
bpf: Allocate ID for bpf_link
Generate ID for each bpf_link using IDR, similarly to bpf_map and bpf_prog.
bpf_link creation, initialization, attachment, and exposing to user-space
through FD and ID is a complicated multi-step process, abstract it away
through bpf_link_primer and bpf_link_prime(), bpf_link_settle(), and
bpf_link_cleanup() internal API. They guarantee that until bpf_link is
properly attached, user-space won't be able to access partially-initialized
bpf_link either from FD or ID. All this allows to simplify bpf_link attachment
and error handling code.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200429001614.1544-3-andriin@fb.com
Diffstat (limited to 'kernel/bpf/cgroup.c')
| -rw-r--r-- | kernel/bpf/cgroup.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index da6e48e802b2..1bdf37fca879 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -841,10 +841,10 @@ const struct bpf_link_ops bpf_cgroup_link_lops = { int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) { + struct bpf_link_primer link_primer; struct bpf_cgroup_link *link; - struct file *link_file; struct cgroup *cgrp; - int err, link_fd; + int err; if (attr->link_create.flags) return -EINVAL; @@ -862,22 +862,20 @@ int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) link->cgroup = cgrp; link->type = attr->link_create.attach_type; - link_file = bpf_link_new_file(&link->link, &link_fd); - if (IS_ERR(link_file)) { + err = bpf_link_prime(&link->link, &link_primer); + if (err) { kfree(link); - err = PTR_ERR(link_file); goto out_put_cgroup; } err = cgroup_bpf_attach(cgrp, NULL, NULL, link, link->type, BPF_F_ALLOW_MULTI); if (err) { - bpf_link_cleanup(&link->link, link_file, link_fd); + bpf_link_cleanup(&link_primer); goto out_put_cgroup; } - fd_install(link_fd, link_file); - return link_fd; + return bpf_link_settle(&link_primer); out_put_cgroup: cgroup_put(cgrp); |