From: Roman Gushchin <[email protected]> When a struct ops is being attached and a bpf link is created, allow to pass a cgroup fd using bpf attr, so that struct ops can be attached to a cgroup instead of globally.
Attached struct ops doesn't hold a reference to the cgroup, only preserves cgroup id. Signed-off-by: Roman Gushchin <[email protected]> --- include/linux/bpf.h | 1 + kernel/bpf/bpf_struct_ops.c | 13 +++++++++++++ 2 files changed, 14 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 031682f1ad39..7c15bac782fc 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1885,6 +1885,7 @@ struct bpf_struct_ops_link { struct bpf_link link; struct bpf_map __rcu *map; wait_queue_head_t wait_hup; + u64 cgroup_id; }; struct bpf_link_primer { diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index de01cf3025b3..f575c5cd0dc8 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -13,6 +13,7 @@ #include <linux/btf_ids.h> #include <linux/rcupdate_wait.h> #include <linux/poll.h> +#include <linux/cgroup.h> struct bpf_struct_ops_value { struct bpf_struct_ops_common_value common; @@ -1377,6 +1378,18 @@ int bpf_struct_ops_link_create(union bpf_attr *attr) } bpf_link_init(&link->link, BPF_LINK_TYPE_STRUCT_OPS, &bpf_struct_ops_map_lops, NULL, attr->link_create.attach_type); +#ifdef CONFIG_CGROUPS + if (attr->link_create.cgroup.relative_fd) { + struct cgroup *cgrp; + + cgrp = cgroup_get_from_fd(attr->link_create.cgroup.relative_fd); + if (IS_ERR(cgrp)) + return PTR_ERR(cgrp); + + link->cgroup_id = cgroup_id(cgrp); + cgroup_put(cgrp); + } +#endif /* CONFIG_CGROUPS */ err = bpf_link_prime(&link->link, &link_primer); if (err) -- 2.43.0
