From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f172.google.com (mail-pf1-f172.google.com [209.85.210.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D9A74378D8D for ; Mon, 16 Mar 2026 11:29:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773660574; cv=none; b=tBAj1k4Pe5tF9Yrp+J3S6tQ3KEhNlGUb7ffp6B5rF4vUTbrp9cTQsZfNY8TN8oatVnBdlkd7tuzfgjOvX4Oz/CATMFB8F1XRC//jievT9hemYVK+1hmcCJcRu9NurWetIBJbT4ssJd/kQzXEBxT4c3210IIapvacSPMM+k6rmLg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773660574; c=relaxed/simple; bh=f254u9m1QCRh+1RTnHbpIKWIkCtIaFhXm7XPT4JMgW0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Wr/xVETBKLkeMQxBo68jUf2L/WkfGwvpcWLMAfVApeDAvQaWCnZxft5z1qqzLVqyJcKSNdh9snMa9jlkmUgBATQ3m82BxCv5ucJFG6kc7CLlpqsikm3uQVWT429+oFIXQpYr9HKWFsgZtlqIj1pkdWedslwd/rsLxiqz4fTTAgg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=IQPRwHW0; arc=none smtp.client-ip=209.85.210.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="IQPRwHW0" Received: by mail-pf1-f172.google.com with SMTP id d2e1a72fcca58-824c9da9928so2877946b3a.3 for ; Mon, 16 Mar 2026 04:29:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1773660571; x=1774265371; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=W2EXT8xQIbLD8Uq3gaj+lgUvs/CfjmF64+/VehA8xmM=; b=IQPRwHW0hdmJVPw/QB5HYZNDRiS8IfS4WLz41X0HY2Wi8q71hSicH9jLwWCntcPxe4 RiF3YoIXAi++m72YWJzYt/jzVQsQ/zWJdVcrwi6JD1IY6oy7/Ek5YOQXiusUo7tGDxJO bCvJo1v5OjpW+UaZN7dhS6XfJx3qWvq20sbck3xG9Ud6NDuKtLylJxLanOr1//J1Vwf1 wPt/ky/KNhLkml5FdBKck+cQJW9ne8NiIKn4dXyCpv9sTMDqYf4/a/VNfGNV1pJAzyNV trgC+OXHldlww/0TJHygLmkC+RQ9ti/iIV0FUlqrwnYyU1pXHFYFZsblfJrmaQipglgL lJSQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1773660571; x=1774265371; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=W2EXT8xQIbLD8Uq3gaj+lgUvs/CfjmF64+/VehA8xmM=; b=AJ3JJKki8wtD4+h/YBtYofAFGWd2O+T4uN8IPIna04ykeuqEf+am6BTRZdyRxAK5Vf WWEvvQ00882xleZxn+DZnEViJB9hSV2vXJN0L7hw39uJ8uRdKYHlssOCjnobLYOY8Ktm kKSDpT4Co1aiaEIMfB5qxHpnU3XB+erTrwG2ewr8u4gFDRg4Ng2eEDsWFA7OLGjcacKa X0SVR1lQxw1SNstjN3uJRxGqFncLlaMq9E1pkkxLxtu/hW7gvVZrWnfdsTnegCURpbG0 jgqFA+UhC+v/D4RCfG/FNC8VW7/TIALBXXzICuKdHhuMEiiwTkrI70B5yjmN7nhc/Ujm aR1g== X-Gm-Message-State: AOJu0YzaIUF+8EUxkGjwZtfxv8my6q4WVCz6mdk+b7cpt+/c0+QlDc+f 3r/zEYfT+zKKuBIoTk6cTQnXZeTNnzE+EA15t3ootbU29bkrsoP9SR4I X-Gm-Gg: ATEYQzzI7OKEXPagIsakxj5mhrQ8r2Xt+fguCVpuQ+0qVFtVYELDHRePInhwzt4yzY2 Iuwts87OUn3s+o2IqR/D+jXH7rK6/tq0agVxNoJWVT4W6U/pUklWxTG/6Up/UGWPM7/HkjLXA5R ru8JiiXsYkRgZtPyb+eL8uIRMbyXqQGCccFnSqJknaK70QJkKcusnQXwSayUNzP/tpg/4hVhFGC eFUhlzUJErrKXHPi6Ih0/e2y6QDpkJjCXjsbqmJ0vkv4m9Ut4Q2tM12pPns2SV54BE8z+X9cqlJ hvDpECMYb2V6FcvbmAzWUbLfrujPXG/IqS7qoOZilpFkbjP/d4Mxa8t+Ms3MLbmKztUFv8TcJvP NzU4KNpPx3TObn19EsMjByvcOO8JXw4MFPvstDoARhOoCwphT8suVVHBIFNmGxmwfWzQSWgRbFR FUVkC94LmoQoCG0zgRT0HBm1YpZZGyIa249wA4BqHywZDHR5lvSfVF4kY= X-Received: by 2002:a05:6a21:7106:b0:398:c3c3:8686 with SMTP id adf61e73a8af0-398eca2d969mr10979592637.4.1773660571067; Mon, 16 Mar 2026 04:29:31 -0700 (PDT) Received: from localhost.localdomain ([116.128.244.171]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c7401588ecesm4684940a12.32.2026.03.16.04.29.24 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Mon, 16 Mar 2026 04:29:30 -0700 (PDT) From: Chengkaitao To: martin.lau@linux.dev, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, shuah@kernel.org, chengkaitao@kylinos.cn, linux-kselftest@vger.kernel.org Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next v8 5/8] bpf: Add bpf_list_add_impl to insert node after a given list node Date: Mon, 16 Mar 2026 19:28:40 +0800 Message-ID: <20260316112843.78657-6-pilgrimtao@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260316112843.78657-1-pilgrimtao@gmail.com> References: <20260316112843.78657-1-pilgrimtao@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Kaitao Cheng Add a new kfunc bpf_list_add_impl(head, new, prev, meta, off) that inserts 'new' after 'prev' in the BPF linked list. Both must be in the same list; 'prev' must already be in the list. The new node must be an owning reference (e.g. from bpf_obj_new); the kfunc consumes that reference and the node becomes non-owning once inserted. We have added an additional parameter bpf_list_head *head to bpf_list_add_impl, as the verifier requires the head parameter to check whether the lock is being held. Returns 0 on success, -EINVAL if 'prev' is not in a list or 'new' is already in a list (or duplicate insertion). On failure, the kernel drops the passed-in node. Signed-off-by: Kaitao Cheng --- kernel/bpf/helpers.c | 14 ++++++++++++++ kernel/bpf/verifier.c | 13 +++++++++++-- 2 files changed, 25 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index a9665f97b3bc..dc4f8b4eec01 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2438,6 +2438,19 @@ __bpf_kfunc int bpf_list_push_back_impl(struct bpf_list_head *head, return __bpf_list_add(new, head, &h->prev, meta ? meta->record : NULL, off); } +__bpf_kfunc int bpf_list_add_impl(struct bpf_list_head *head, + struct bpf_list_node *new, + struct bpf_list_node *prev, + void *meta__ign, u64 off) +{ + struct bpf_list_node_kern *kn = (void *)new, *kp = (void *)prev; + struct btf_struct_meta *meta = meta__ign; + struct list_head *prev_ptr = &kp->list_head; + + return __bpf_list_add(kn, head, &prev_ptr, + meta ? meta->record : NULL, off); +} + static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, struct list_head *n) { @@ -4574,6 +4587,7 @@ BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_list_del, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_list_front, KF_RET_NULL) BTF_ID_FLAGS(func, bpf_list_back, KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_list_add_impl) BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_RCU | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_task_release, KF_RELEASE) BTF_ID_FLAGS(func, bpf_rbtree_remove, KF_ACQUIRE | KF_RET_NULL) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index e928ad4290c7..98ddb370feb5 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -12506,6 +12506,7 @@ enum special_kfunc_type { KF_bpf_refcount_acquire_impl, KF_bpf_list_push_front_impl, KF_bpf_list_push_back_impl, + KF_bpf_list_add_impl, KF_bpf_list_pop_front, KF_bpf_list_pop_back, KF_bpf_list_del, @@ -12567,6 +12568,7 @@ BTF_ID(func, bpf_obj_drop_impl) BTF_ID(func, bpf_refcount_acquire_impl) BTF_ID(func, bpf_list_push_front_impl) BTF_ID(func, bpf_list_push_back_impl) +BTF_ID(func, bpf_list_add_impl) BTF_ID(func, bpf_list_pop_front) BTF_ID(func, bpf_list_pop_back) BTF_ID(func, bpf_list_del) @@ -12644,6 +12646,7 @@ BTF_ID(func, bpf_stream_print_stack) static const enum special_kfunc_type bpf_list_api_kfuncs[] = { KF_bpf_list_push_front_impl, KF_bpf_list_push_back_impl, + KF_bpf_list_add_impl, KF_bpf_list_pop_front, KF_bpf_list_pop_back, KF_bpf_list_del, @@ -12655,6 +12658,7 @@ static const enum special_kfunc_type bpf_list_api_kfuncs[] = { static const enum special_kfunc_type bpf_list_node_api_kfuncs[] = { KF_bpf_list_push_front_impl, KF_bpf_list_push_back_impl, + KF_bpf_list_add_impl, KF_bpf_list_del, }; @@ -14345,6 +14349,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, if (meta.func_id == special_kfunc_list[KF_bpf_list_push_front_impl] || meta.func_id == special_kfunc_list[KF_bpf_list_push_back_impl] || + meta.func_id == special_kfunc_list[KF_bpf_list_add_impl] || meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) { release_ref_obj_id = regs[BPF_REG_2].ref_obj_id; insn_aux->insert_off = regs[BPF_REG_2].var_off.value; @@ -23357,13 +23362,17 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, *cnt = 3; } else if (desc->func_id == special_kfunc_list[KF_bpf_list_push_back_impl] || desc->func_id == special_kfunc_list[KF_bpf_list_push_front_impl] || + desc->func_id == special_kfunc_list[KF_bpf_list_add_impl] || desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) { struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta; int struct_meta_reg = BPF_REG_3; int node_offset_reg = BPF_REG_4; - /* rbtree_add has extra 'less' arg, so args-to-fixup are in diff regs */ - if (desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) { + /* list/rbtree_add_impl have an extra arg (prev/less), + * so args-to-fixup are in different regs. + */ + if (desc->func_id == special_kfunc_list[KF_bpf_list_add_impl] || + desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) { struct_meta_reg = BPF_REG_4; node_offset_reg = BPF_REG_5; } -- 2.50.1 (Apple Git-155)