Re: [PATCH bpf-next v2 01/15] bpf: Remove __rcu tagging in st_link->map

[PATCH bpf-next v2 00/15] bpf: A common way to attach struct_ops to a cgroup · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 01/15] bpf: Remove __rcu tagging in st_link->map · Amery Hung <hidden> · 2026-06-23
Re: [PATCH bpf-next v2 01/15] bpf: Remove __rcu tagging in st_link->map · Eduard Zingerman <eddyz87@gmail.com> · 2026-06-26
[PATCH bpf-next v2 02/15] bpf: Make struct_ops tasks_rcu grace period optional · Amery Hung <hidden> · 2026-06-23
Re: [PATCH bpf-next v2 02/15] bpf: Make struct_ops tasks_rcu grace period optional · Eduard Zingerman <eddyz87@gmail.com> · 2026-06-26
[PATCH bpf-next v2 03/15] bpf: Add bpf_struct_ops accessor helpers · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 04/15] bpf: Remove unnecessary prog_list_prog() check · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 05/15] bpf: Replace prog_list_prog() check with direct pl->prog and pl->link check · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 06/15] bpf: Add prog_list_init_item(), prog_list_replace_item(), and prog_list_id() · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 07/15] bpf: Move LSM trampoline unlink into bpf_cgroup_link_auto_detach() · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 08/15] bpf: Add a few bpf_cgroup_array_* helper functions · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 09/15] bpf: Add infrastructure to support attaching struct_ops to cgroups · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 10/15] bpf: Allow all struct_ops to use bpf_dynptr_from_skb() · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 11/15] bpf: tcp: Support selected sock_ops callbacks as struct_ops · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 12/15] bpf: tcp: Support parse/len/write header option hooks in bpf_tcp_ops · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 13/15] libbpf: Support attaching struct_ops to a cgroup · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 14/15] selftests/bpf: Test attaching struct_ops to a cgroup · Amery Hung <hidden> · 2026-06-23
[PATCH bpf-next v2 15/15] selftests/bpf: Add test for bpf_tcp_ops header option hooks · Amery Hung <hidden> · 2026-06-23

From: Eduard Zingerman <eddyz87@gmail.com>
Date: 2026-06-26 18:52:10
Also in: bpf

On Tue, 2026-06-23 at 10:49 -0700, Amery Hung wrote:

From: Martin KaFai Lau <martin.lau@kernel.org>

st_link->map is always written under update_mutex. The paths that read
st_link->map with rcu_read_lock() are not in the fast path, so they can
simply take update_mutex instead. Remove the __rcu annotation and replace
all RCU accessors with direct pointer reads under update_mutex. Use
READ_ONCE() in bpf_struct_ops_map_link_poll() which reads the pointer
without holding update_mutex.

It is a simplification change.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Amery Hung <redacted>
---

Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>

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