[PATCH bpf-next v2 06/15] bpf: Add prog_list_init_item(), prog_list_replace_item(), and prog_list_id()
From: Amery Hung <hidden>
Date: 2026-06-23 17:50:17
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
From: Martin KaFai Lau <martin.lau@kernel.org> Add three helpers to abstract operations on a bpf_prog_list entry. Right now, bpf_prog_array_item is initialized from prog_list_prog(pl), which returns either pl->prog or pl->link->link.prog. This will not work when struct_ops is attached to a cgroup because the attachment is backed by a struct_ops map instead of a BPF prog. The same applies to __cgroup_bpf_query(). Instead of always copying a prog id to userspace, struct_ops cgroup attachment will need to copy the struct_ops map id. Refactor bpf_prog_array_item initialization into prog_list_init_item() and prog_list_replace_item(), and refactor id lookup into prog_list_id(). These helpers will be extended to support pl->link->map in a later patch. This is a no-op change. Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Amery Hung <redacted> --- kernel/bpf/cgroup.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-)
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index b100c04cb9c8..b43f0bff184c 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c@@ -399,6 +399,22 @@ static struct bpf_prog *prog_list_prog(struct bpf_prog_list *pl) return NULL; } +static void prog_list_init_item(struct bpf_prog_list *pl, struct bpf_prog_array_item *item) +{ + item->prog = prog_list_prog(pl); + bpf_cgroup_storages_assign(item->cgroup_storage, pl->storage); +} + +static void prog_list_replace_item(struct bpf_prog_list *pl, struct bpf_prog_array_item *item) +{ + WRITE_ONCE(item->prog, pl->link->link.prog); +} + +static u32 prog_list_id(struct bpf_prog_list *pl) +{ + return prog_list_prog(pl)->aux->id; +} + /* count number of elements in the list. * it's slow but the list cannot be long */
@@ -492,9 +508,7 @@ static int compute_effective_progs(struct cgroup *cgrp, item = &progs->items[fstart]; fstart++; } - item->prog = prog_list_prog(pl); - bpf_cgroup_storages_assign(item->cgroup_storage, - pl->storage); + prog_list_init_item(pl, item); cnt++; }
@@ -1015,7 +1029,7 @@ static void replace_effective_prog(struct cgroup *cgrp, desc->bpf.effective[atype], lockdep_is_held(&cgroup_mutex)); item = &progs->items[pos]; - WRITE_ONCE(item->prog, pl->link->link.prog); + prog_list_replace_item(pl, item); } }
@@ -1318,15 +1332,13 @@ static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, } else { struct hlist_head *progs; struct bpf_prog_list *pl; - struct bpf_prog *prog; u32 id; progs = &cgrp->bpf.progs[atype]; cnt = min_t(int, prog_list_length(progs, NULL), total_cnt); i = 0; hlist_for_each_entry(pl, progs, node) { - prog = prog_list_prog(pl); - id = prog->aux->id; + id = prog_list_id(pl); if (copy_to_user(prog_ids + i, &id, sizeof(id))) return -EFAULT; if (++i == cnt)
--
2.53.0-Meta