From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 977BF3D47DD; Wed, 20 May 2026 23:50:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779321061; cv=none; b=HDHbguAOxgT25/HAIQiKK2lydHLP6CuTOX3441AZP9Z5COm5Affa7v8YpB44VyH7oN54JWMCyWXi5xKWfaqgX0rc9XJFENzTVhVdyysunKS2XlnGFnUcrRCYqoHIiRhyeJMG8JDaAu8nMubWDnaKuUjhSufpE+Uoi7jWDAWoS5g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779321061; c=relaxed/simple; bh=cstOV2+2ci8zXNA1Qt+GQw2l2x7LM8SwWqJ3hidZguY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZtDyoi4PjW+mEV/3/2+qlJP+SkRDiRuxcR6VQx6VKujN2gKkiivk0Z8AP6Ilrclt78zd3Qt7Zp3h8xe0aEoI9s9cCY8jSv00MiQvYlkkMY2I6LvRrbJj/d23lQoUdnYU3NoH5UznflH9soBOywslfC3NQDEgphytHsLBioH0VLQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=APzU+iQv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="APzU+iQv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 464B71F00A3E; Wed, 20 May 2026 23:50:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779321057; bh=xK8/4hQ0j9g1pID7Vdqyu8/i/yh91hlV7Ni1mBkOJ+0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=APzU+iQv4rh0acB52YSaIyInFGYquGdEFeHHg3Fl9plQlL7b7DbLT+9iJfSaFsLcx MkmbH9ysihwjXG9bUD1tTnDPczpxmmhKRbNEU0fDa3OcDDPhVzxSUohYpXiDJhAdo4 7WfnC7nLPVEt2oHSckKZRJFvHnoqdCw3llehZ7zK4wnPubZuOnW/3UZDe46a0Nn/Vb x0C57aQKa2p/VbfZEu01bvgSVUCCwQvIb6tfiYimIML+VtIeGozykQeicAk1xDrEV0 uvgLtPjdtbNZ7J5c02Neqnf+iayG22GobtiwFjl1JbKJKk6uEIWNUYLuPOgGnoXdse W+asDJLa6Of8g== From: Tejun Heo To: David Vernet , Andrea Righi , Changwoo Min , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Kumar Kartikeya Dwivedi Cc: Peter Zijlstra , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Andrew Morton , David Hildenbrand , Mike Rapoport , Emil Tsalapatis , sched-ext@lists.linux.dev, bpf@vger.kernel.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 4/8] bpf: Add bpf_struct_ops_for_each_prog() Date: Wed, 20 May 2026 13:50:48 -1000 Message-ID: <20260520235052.4180316-5-tj@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520235052.4180316-1-tj@kernel.org> References: <20260520235052.4180316-1-tj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add a helper that walks the member progs of the struct_ops map containing a given @kdata vmtable. struct_ops ->reg() callbacks (and similar) sometimes need to inspect the loaded BPF programs, e.g. to discover maps they reference via prog->aux->used_maps. The implementation mirrors bpf_struct_ops_id(): container_of @kdata to recover the bpf_struct_ops_map, then iterate st_map->links[i]->prog for i in [0, funcs_cnt). Same access pattern, no new locking - by the time ->reg() fires st_map is fully populated and stable. A sched_ext follow-up walks the member progs of a cid-form scheduler's struct_ops map, reads prog->aux->arena directly, and requires all member progs to reference exactly one arena, without requiring the BPF program to call a registration kfunc. Signed-off-by: Tejun Heo --- include/linux/bpf.h | 3 +++ kernel/bpf/bpf_struct_ops.c | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 64968ca6db51..5b99d786e98c 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2129,6 +2129,9 @@ int bpf_prog_assoc_struct_ops(struct bpf_prog *prog, struct bpf_map *map); void bpf_prog_disassoc_struct_ops(struct bpf_prog *prog); void *bpf_prog_get_assoc_struct_ops(const struct bpf_prog_aux *aux); u32 bpf_struct_ops_id(const void *kdata); +int bpf_struct_ops_for_each_prog(const void *kdata, + int (*cb)(struct bpf_prog *prog, void *data), + void *data); #ifdef CONFIG_NET /* Define it here to avoid the use of forward declaration */ diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index 05b366b821c3..16aec18ed31b 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -1203,6 +1203,42 @@ u32 bpf_struct_ops_id(const void *kdata) } EXPORT_SYMBOL_GPL(bpf_struct_ops_id); +/** + * bpf_struct_ops_for_each_prog - Invoke @cb for each member prog + * @kdata: kernel-side struct_ops vmtable (the @kdata arg to ->reg/->update/->unreg) + * @cb: callback invoked once per member prog; non-zero return stops iteration + * @data: opaque argument passed to @cb + * + * Walks the struct_ops member progs registered on the map containing @kdata. + * Intended for use from struct_ops ->reg() callbacks (and similar) that need to + * inspect the loaded BPF programs (for example to discover maps they reference + * via @prog->aux->used_maps). + * + * Return 0 if iteration completed, otherwise the first non-zero @cb return. + */ +int bpf_struct_ops_for_each_prog(const void *kdata, + int (*cb)(struct bpf_prog *prog, void *data), + void *data) +{ + struct bpf_struct_ops_value *kvalue; + struct bpf_struct_ops_map *st_map; + u32 i; + int ret; + + kvalue = container_of(kdata, struct bpf_struct_ops_value, data); + st_map = container_of(kvalue, struct bpf_struct_ops_map, kvalue); + + for (i = 0; i < st_map->funcs_cnt; i++) { + if (!st_map->links[i]) + continue; + ret = cb(st_map->links[i]->prog, data); + if (ret) + return ret; + } + return 0; +} +EXPORT_SYMBOL_GPL(bpf_struct_ops_for_each_prog); + static bool bpf_struct_ops_valid_to_reg(struct bpf_map *map) { struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map; -- 2.54.0