From patchwork Sun Feb 25 10:06:36 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 13570792 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mail-pf1-f178.google.com (mail-pf1-f178.google.com [209.85.210.178]) (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 3D08FEECC for ; Sun, 25 Feb 2024 10:07:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.178 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708855637; cv=none; b=B4vL6czRbBKWCxYeYFhjw9yDe3+iP/q9LeMp5eW84YpzFmsvqDxbrS+aNIcd+h/lXbn6Y4MXI25UgpURN3F0Ng/VUdVgSn4j7FkjZKJIOlFJqtiprqnSxhOfk9ZkTbXE58mKpcS30PptZ3x2x8R2qqldVl/UZNqMGQyomB6kVGI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708855637; c=relaxed/simple; bh=nChb07pOeK3EsX4BcusRj+XZ0FIXGLVJzOik27zHZLQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=fB8nEGF8L1GmUYKQ0gO+NvT88i1KYUmlPSdR49grD854AZwELzgGoWK7H0J8Fs0p5QhRexHqf3od/KAlSQzYwdcEosGkwoiQ4QsWz24l5wyDXoINc8CkMvW9GRXoEe8ZopkEgIvyZBxzs2Kz1ydf1rHS7P80jgW/nqmfwLHvyJk= 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=YNEv5+Mm; arc=none smtp.client-ip=209.85.210.178 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="YNEv5+Mm" Received: by mail-pf1-f178.google.com with SMTP id d2e1a72fcca58-6e4670921a4so1068820b3a.0 for ; Sun, 25 Feb 2024 02:07:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1708855635; x=1709460435; 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=SQ9hOlFaZS0Phz9aoHEeng0yjo+m6s3+02Ag/Yo2l5M=; b=YNEv5+MmJM0twr8QYKy99a6x61UuOuIdMaao4XYQgE0UiVFFqkLTb1c3TW9uIweVNw rFB2XwUUNCaaXO2NlfPdwfKmiQ30Ga5xVIG2DuNLFcT07MYgjkmwZuqx231vcZTnIGBM tTMiKQBcjN0xmfvku8B5JY27mj0/BzoGpx7i5v30WCsOVtqGUzVutqjNbagDt5zpvVPx WMzEp1Dp48T3Zh/xNCt8oOjF1kSD0/8RPTOvbSW9FXBosu4+6Gaw63DKR7fEAS5Sdrhg su5S0wb29AeYxEt9HBR4vKShJt0vVTVt5knc5VBxwhvXAb4jSYL49M5007g3k44PDChP 0XEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1708855635; x=1709460435; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=SQ9hOlFaZS0Phz9aoHEeng0yjo+m6s3+02Ag/Yo2l5M=; b=UYeSC9cpsnH8xSdyGUO/ZImXHZZtkESsSC+TfIIsV36K6fPoe3fPeZNvzpu5x/OsSR tnmWvpbBV3x/i86lfw0S2oV1MR+WgbsWP18Q8rAfPrNeCKBun2CZCKofUmWderE1Fw14 Y3s4fuAw3d0+qyGhq/h9Wv+Fu3G4UlgHchL3K7bxeNjStYKrKZAM4L72gOI7jW8H8Ja5 K0kS5eyjB5ZWrd42qCgMYmS3VOXFM359/2+UUHO/yKMHYyyfSoo0bWnbC0ATCx54UmKW xfxbA+Rrt1g/IazGgTHuzhibAjwBK/dfBgg3j01upFI6myumJk1Cvm5IqtODQjl1M4P4 B55Q== X-Gm-Message-State: AOJu0YxI+nfms0+UgzEaq45SXUY5/10/YE6Voa+Trq1ayA+IQNoNWMK5 dRSXpkp8vAqFEad35n7SkFHzWNZo1cHOPL1GlAqjGtrAXztFhUBE X-Google-Smtp-Source: AGHT+IHBcXcx2623M0whrWlzgiI3kQqCI25eENer+Z4CovcjDG3arP6UR+R6uyNsg3naH2Iai93MxA== X-Received: by 2002:a05:6a00:1798:b0:6e5:dd3:b343 with SMTP id s24-20020a056a00179800b006e50dd3b343mr993035pfg.34.1708855635535; Sun, 25 Feb 2024 02:07:15 -0800 (PST) Received: from localhost.localdomain ([39.144.104.176]) by smtp.gmail.com with ESMTPSA id f26-20020aa79d9a000000b006e1464e71f9sm2119775pfq.47.2024.02.25.02.07.08 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 25 Feb 2024 02:07:14 -0800 (PST) From: Yafang Shao To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org Cc: bpf@vger.kernel.org, Yafang Shao Subject: [PATCH v2 bpf-next 1/2] bpf: Add bits iterator Date: Sun, 25 Feb 2024 18:06:36 +0800 Message-Id: <20240225100637.48394-2-laoar.shao@gmail.com> X-Mailer: git-send-email 2.30.1 (Apple Git-130) In-Reply-To: <20240225100637.48394-1-laoar.shao@gmail.com> References: <20240225100637.48394-1-laoar.shao@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Add three new kfuncs for the bits iterator: - bpf_iter_bits_new Initialize a new bits iterator for a given memory area. Due to the limitation of bpf memalloc, the max number of bits that can be iterated over is limited to (4096 * 8). - bpf_iter_bits_next Get the next bit in a bpf_iter_bits - bpf_iter_bits_destroy Destroy a bpf_iter_bits The bits iterator facilitates the iteration of the bits of a memory area, such as cpumask. It can be used in any context and on any address. Signed-off-by: Yafang Shao --- kernel/bpf/helpers.c | 100 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 93edf730d288..052f63891834 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2542,6 +2542,103 @@ __bpf_kfunc void bpf_throw(u64 cookie) WARN(1, "A call to BPF exception callback should never return\n"); } +struct bpf_iter_bits { + __u64 __opaque[2]; +} __aligned(8); + +struct bpf_iter_bits_kern { + unsigned long *bits; + u32 nr_bits; + int bit; +} __aligned(8); + +/** + * bpf_iter_bits_new() - Initialize a new bits iterator for a given memory area + * @it: The new bpf_iter_bits to be created + * @unsafe_ptr__ign: A ponter pointing to a memory area to be iterated over + * @nr_bits: The number of bits to be iterated over. Due to the limitation of + * memalloc, it can't greater than (4096 * 8). + * + * This function initializes a new bpf_iter_bits structure for iterating over + * a memory area which is specified by the @unsafe_ptr__ign and @nr_bits. It + * copy the data of the memory area to the newly created bpf_iter_bits @it for + * subsequent iteration operations. + * + * On success, 0 is returned. On failure, ERR is returned. + */ +__bpf_kfunc int +bpf_iter_bits_new(struct bpf_iter_bits *it, const void *unsafe_ptr__ign, u32 nr_bits) +{ + struct bpf_iter_bits_kern *kit = (void *)it; + u32 size = BITS_TO_BYTES(nr_bits); + int err; + + BUILD_BUG_ON(sizeof(struct bpf_iter_bits_kern) != sizeof(struct bpf_iter_bits)); + BUILD_BUG_ON(__alignof__(struct bpf_iter_bits_kern) != + __alignof__(struct bpf_iter_bits)); + + if (!unsafe_ptr__ign || !nr_bits) { + kit->bits = NULL; + return -EINVAL; + } + + kit->bits = bpf_mem_alloc(&bpf_global_ma, size); + if (!kit->bits) + return -ENOMEM; + + err = bpf_probe_read_kernel_common(kit->bits, size, unsafe_ptr__ign); + if (err) { + bpf_mem_free(&bpf_global_ma, kit->bits); + kit->bits = NULL; + return err; + } + + kit->nr_bits = nr_bits; + kit->bit = -1; + return 0; +} + +/** + * bpf_iter_bits_next() - Get the next bit in a bpf_iter_bits + * @it: The bpf_iter_bits to be checked + * + * This function returns a pointer to a number representing the value of the + * next bit in the bits. + * + * If there are no further bit available, it returns NULL. + */ +__bpf_kfunc int *bpf_iter_bits_next(struct bpf_iter_bits *it) +{ + struct bpf_iter_bits_kern *kit = (void *)it; + const unsigned long *bits = kit->bits; + int bit; + + if (!bits) + return NULL; + + bit = find_next_bit(bits, kit->nr_bits, kit->bit + 1); + if (bit >= kit->nr_bits) + return NULL; + + kit->bit = bit; + return &kit->bit; +} + +/** + * bpf_iter_bits_destroy() - Destroy a bpf_iter_bits + * @it: The bpf_iter_bits to be destroyed + * + * Destroy the resource associated with the bpf_iter_bits. + */ +__bpf_kfunc void bpf_iter_bits_destroy(struct bpf_iter_bits *it) +{ + struct bpf_iter_bits_kern *kit = (void *)it; + + if (!kit->bits) + return; + bpf_mem_free(&bpf_global_ma, kit->bits); +} + __bpf_kfunc_end_defs(); BTF_KFUNCS_START(generic_btf_ids) @@ -2618,6 +2715,9 @@ BTF_ID_FLAGS(func, bpf_dynptr_is_null) BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly) BTF_ID_FLAGS(func, bpf_dynptr_size) BTF_ID_FLAGS(func, bpf_dynptr_clone) +BTF_ID_FLAGS(func, bpf_iter_bits_new, KF_ITER_NEW) +BTF_ID_FLAGS(func, bpf_iter_bits_next, KF_ITER_NEXT | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_iter_bits_destroy, KF_ITER_DESTROY) BTF_KFUNCS_END(common_btf_ids) static const struct btf_kfunc_id_set common_kfunc_set = {