From: Martin KaFai Lau <martin.lau@linux.dev>
To: bpf@vger.kernel.org
Cc: 'Alexei Starovoitov ' <ast@kernel.org>,
'Andrii Nakryiko ' <andrii@kernel.org>,
'Daniel Borkmann ' <daniel@iogearbox.net>,
'Shakeel Butt ' <shakeel.butt@linux.dev>,
'Roman Gushchin ' <roman.gushchin@linux.dev>,
'Amery Hung ' <ameryhung@gmail.com>,
netdev@vger.kernel.org
Subject: [RFC PATCH bpf-next 05/12] bpf: Replace prog_list_prog() check with direct pl->prog and pl->link check
Date: Tue, 19 May 2026 14:58:12 -0700 [thread overview]
Message-ID: <20260519215841.2984970-6-martin.lau@linux.dev> (raw)
In-Reply-To: <20260519215841.2984970-1-martin.lau@linux.dev>
From: Martin KaFai Lau <martin.lau@kernel.org>
prog_list_length() and compute_effective_progs() use !prog_list_prog(pl)
to skip a 'detaching' pl.
When pl->link is not NULL, prog_list_prog(pl) returns
the pl->link->link.prog. This does not work for the upcoming struct_ops
patch where pl->link is not NULL but pl->link->link.prog is NULL,
because a struct_ops map is attached to the cgroup instead of a BPF prog.
To prepare for the upcoming struct_ops patch, this patch
replaces the prog_list_prog() test with the
"!pl->prog && !pl->link". In __cgroup_bpf_detach(),
both pl->prog and pl->link are set to NULL, so testing
"!pl->prog && !pl->link" is the same test to tell
if a pl is being detached. This change should be a no-op.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
kernel/bpf/cgroup.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 71591f6dc458..abfd6df349d4 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -387,7 +387,7 @@ static u32 prog_list_length(struct hlist_head *head, int *preorder_cnt)
u32 cnt = 0;
hlist_for_each_entry(pl, head, node) {
- if (!prog_list_prog(pl))
+ if (!pl->prog && !pl->link)
continue;
if (preorder_cnt && (pl->flags & BPF_F_PREORDER))
(*preorder_cnt)++;
@@ -461,7 +461,7 @@ static int compute_effective_progs(struct cgroup *cgrp,
init_bstart = bstart;
hlist_for_each_entry(pl, &p->bpf.progs[atype], node) {
- if (!prog_list_prog(pl))
+ if (!pl->prog && !pl->link)
continue;
if (pl->flags & BPF_F_PREORDER) {
--
2.53.0-Meta
next prev parent reply other threads:[~2026-05-19 21:59 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-19 21:58 [RFC PATCH bpf-next 00/12] bpf: A common way to attach struct_ops to a cgroup Martin KaFai Lau
2026-05-19 21:58 ` [RFC PATCH bpf-next 01/12] bpf: Remove __rcu tagging in st_link->map Martin KaFai Lau
2026-05-19 21:58 ` [RFC PATCH bpf-next 02/12] bpf: Make struct_ops tasks_rcu grace period optional Martin KaFai Lau
2026-05-19 21:58 ` [RFC PATCH bpf-next 03/12] bpf: Add bpf_struct_ops accessor helpers Martin KaFai Lau
2026-05-19 21:58 ` [RFC PATCH bpf-next 04/12] bpf: Remove unnecessary prog_list_prog() check Martin KaFai Lau
2026-05-19 21:58 ` Martin KaFai Lau [this message]
2026-05-19 21:58 ` [RFC PATCH bpf-next 06/12] bpf: Add prog_list_init_item(), prog_list_replace_item(), and prog_list_id() Martin KaFai Lau
2026-05-19 21:58 ` [RFC PATCH bpf-next 07/12] bpf: Move LSM trampoline unlink into bpf_cgroup_link_auto_detach() Martin KaFai Lau
2026-05-19 21:58 ` [RFC PATCH bpf-next 08/12] bpf: Add a few bpf_cgroup_array_* helper functions Martin KaFai Lau
2026-05-19 21:58 ` [RFC PATCH bpf-next 09/12] bpf: Add infrastructure to support attaching struct_ops to cgroups Martin KaFai Lau
2026-05-19 21:58 ` [RFC PATCH bpf-next 10/12] bpf: tcp: Support selected sock_ops callbacks as struct_ops Martin KaFai Lau
2026-05-19 21:58 ` [RFC PATCH bpf-next 11/12] libbpf: Support attaching struct_ops to a cgroup Martin KaFai Lau
2026-05-19 21:58 ` [RFC PATCH bpf-next 12/12] selftests/bpf: Test " Martin KaFai Lau
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