From patchwork Thu Jan 13 00:28:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Iwashima, Kuniyuki" X-Patchwork-Id: 12712119 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74CF4C433F5 for ; Thu, 13 Jan 2022 00:29:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229642AbiAMA3m (ORCPT ); Wed, 12 Jan 2022 19:29:42 -0500 Received: from smtp-fw-80006.amazon.com ([99.78.197.217]:16904 "EHLO smtp-fw-80006.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229651AbiAMA3h (ORCPT ); Wed, 12 Jan 2022 19:29:37 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.co.jp; i=@amazon.co.jp; q=dns/txt; s=amazon201209; t=1642033778; x=1673569778; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=K7MkisJVBiDUaiAf2EEmBDAI3EzW+pc2moDk2I1EeyY=; b=hr10NaXtEVLxAzGn964EH7pcb1e/R4q42Yfyaywy1tMbKa72GMpf4Eaq 0tbAOa74d/svRtVU3xzkdBP7PM/oQYtJUBwR3+mgYe7pgke/M8J+DTBSK iggipjB/wqWZ/omimlFipA9u7Y61iC7pQfp/RRlB0KB/yDfgaL9UinkRb w=; X-IronPort-AV: E=Sophos;i="5.88,284,1635206400"; d="scan'208";a="54965278" Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO email-inbound-relay-iad-1a-87b71607.us-east-1.amazon.com) ([10.25.36.214]) by smtp-border-fw-80006.pdx80.corp.amazon.com with ESMTP; 13 Jan 2022 00:29:36 +0000 Received: from EX13MTAUWB001.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan3.iad.amazon.com [10.40.163.38]) by email-inbound-relay-iad-1a-87b71607.us-east-1.amazon.com (Postfix) with ESMTPS id B087A14111E; Thu, 13 Jan 2022 00:29:34 +0000 (UTC) Received: from EX13D04ANC001.ant.amazon.com (10.43.157.89) by EX13MTAUWB001.ant.amazon.com (10.43.161.249) with Microsoft SMTP Server (TLS) id 15.0.1497.28; Thu, 13 Jan 2022 00:29:33 +0000 Received: from 88665a182662.ant.amazon.com (10.43.161.142) by EX13D04ANC001.ant.amazon.com (10.43.157.89) with Microsoft SMTP Server (TLS) id 15.0.1497.26; Thu, 13 Jan 2022 00:29:29 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Jakub Kicinski , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko CC: Martin KaFai Lau , Benjamin Herrenschmidt , Kuniyuki Iwashima , Kuniyuki Iwashima , , Subject: [PATCH v2 bpf-next 2/5] bpf: af_unix: Use batching algorithm in bpf unix iter. Date: Thu, 13 Jan 2022 09:28:46 +0900 Message-ID: <20220113002849.4384-3-kuniyu@amazon.co.jp> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220113002849.4384-1-kuniyu@amazon.co.jp> References: <20220113002849.4384-1-kuniyu@amazon.co.jp> MIME-Version: 1.0 X-Originating-IP: [10.43.161.142] X-ClientProxiedBy: EX13D04UWB001.ant.amazon.com (10.43.161.46) To EX13D04ANC001.ant.amazon.com (10.43.157.89) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net The commit 04c7820b776f ("bpf: tcp: Bpf iter batching and lock_sock") introduces the batching algorithm to iterate TCP sockets with more consistency. This patch uses the same algorithm to iterate AF_UNIX sockets. Signed-off-by: Kuniyuki Iwashima --- net/unix/af_unix.c | 184 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 177 insertions(+), 7 deletions(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index e1c4082accdb..d383d5f63b6b 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -3356,6 +3356,15 @@ static const struct seq_operations unix_seq_ops = { }; #if IS_BUILTIN(CONFIG_UNIX) && defined(CONFIG_BPF_SYSCALL) +struct bpf_unix_iter_state { + struct seq_net_private p; + unsigned int cur_sk; + unsigned int end_sk; + unsigned int max_sk; + struct sock **batch; + bool st_bucket_done; +}; + struct bpf_iter__unix { __bpf_md_ptr(struct bpf_iter_meta *, meta); __bpf_md_ptr(struct unix_sock *, unix_sk); @@ -3374,24 +3383,156 @@ static int unix_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta, return bpf_iter_run_prog(prog, &ctx); } +static int bpf_iter_unix_hold_batch(struct seq_file *seq, struct sock *start_sk) + +{ + struct bpf_unix_iter_state *iter = seq->private; + unsigned int expected = 1; + struct sock *sk; + + sock_hold(start_sk); + iter->batch[iter->end_sk++] = start_sk; + + for (sk = sk_next(start_sk); sk; sk = sk_next(sk)) { + if (sock_net(sk) != seq_file_net(seq)) + continue; + + if (iter->end_sk < iter->max_sk) { + sock_hold(sk); + iter->batch[iter->end_sk++] = sk; + } + + expected++; + } + + spin_unlock(&unix_table_locks[start_sk->sk_hash]); + + return expected; +} + +static void bpf_iter_unix_put_batch(struct bpf_unix_iter_state *iter) +{ + while (iter->cur_sk < iter->end_sk) + sock_put(iter->batch[iter->cur_sk++]); +} + +static int bpf_iter_unix_realloc_batch(struct bpf_unix_iter_state *iter, + unsigned int new_batch_sz) +{ + struct sock **new_batch; + + new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz, + GFP_USER | __GFP_NOWARN); + if (!new_batch) + return -ENOMEM; + + bpf_iter_unix_put_batch(iter); + kvfree(iter->batch); + iter->batch = new_batch; + iter->max_sk = new_batch_sz; + + return 0; +} + +static struct sock *bpf_iter_unix_batch(struct seq_file *seq, + loff_t *pos) +{ + struct bpf_unix_iter_state *iter = seq->private; + unsigned int expected; + bool resized = false; + struct sock *sk; + + if (iter->st_bucket_done) + *pos = set_bucket_offset(get_bucket(*pos) + 1, 1); + +again: + /* Get a new batch */ + iter->cur_sk = 0; + iter->end_sk = 0; + + sk = unix_get_first(seq, pos); + if (!sk) + return NULL; /* Done */ + + expected = bpf_iter_unix_hold_batch(seq, sk); + + if (iter->end_sk == expected) { + iter->st_bucket_done = true; + return sk; + } + + if (!resized && !bpf_iter_unix_realloc_batch(iter, expected * 3 / 2)) { + resized = true; + goto again; + } + + return sk; +} + +static void *bpf_iter_unix_seq_start(struct seq_file *seq, loff_t *pos) +{ + if (!*pos) + return SEQ_START_TOKEN; + + /* bpf iter does not support lseek, so it always + * continue from where it was stop()-ped. + */ + return bpf_iter_unix_batch(seq, pos); +} + +static void *bpf_iter_unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + struct bpf_unix_iter_state *iter = seq->private; + struct sock *sk; + + /* Whenever seq_next() is called, the iter->cur_sk is + * done with seq_show(), so advance to the next sk in + * the batch. + */ + if (iter->cur_sk < iter->end_sk) + sock_put(iter->batch[iter->cur_sk++]); + + ++*pos; + + if (iter->cur_sk < iter->end_sk) + sk = iter->batch[iter->cur_sk]; + else + sk = bpf_iter_unix_batch(seq, pos); + + return sk; +} + static int bpf_iter_unix_seq_show(struct seq_file *seq, void *v) { struct bpf_iter_meta meta; struct bpf_prog *prog; struct sock *sk = v; uid_t uid; + bool slow; + int ret; if (v == SEQ_START_TOKEN) return 0; + slow = lock_sock_fast(sk); + + if (unlikely(sk_unhashed(sk))) { + ret = SEQ_SKIP; + goto unlock; + } + uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)); meta.seq = seq; prog = bpf_iter_get_info(&meta, false); - return unix_prog_seq_show(prog, &meta, v, uid); + ret = unix_prog_seq_show(prog, &meta, v, uid); +unlock: + unlock_sock_fast(sk, slow); + return ret; } static void bpf_iter_unix_seq_stop(struct seq_file *seq, void *v) { + struct bpf_unix_iter_state *iter = seq->private; struct bpf_iter_meta meta; struct bpf_prog *prog; @@ -3402,12 +3543,13 @@ static void bpf_iter_unix_seq_stop(struct seq_file *seq, void *v) (void)unix_prog_seq_show(prog, &meta, v, 0); } - unix_seq_stop(seq, v); + if (iter->cur_sk < iter->end_sk) + bpf_iter_unix_put_batch(iter); } static const struct seq_operations bpf_iter_unix_seq_ops = { - .start = unix_seq_start, - .next = unix_seq_next, + .start = bpf_iter_unix_seq_start, + .next = bpf_iter_unix_seq_next, .stop = bpf_iter_unix_seq_stop, .show = bpf_iter_unix_seq_show, }; @@ -3456,11 +3598,39 @@ static struct pernet_operations unix_net_ops = { DEFINE_BPF_ITER_FUNC(unix, struct bpf_iter_meta *meta, struct unix_sock *unix_sk, uid_t uid) +#define INIT_BATCH_SZ 16 + +static int bpf_iter_init_unix(void *priv_data, struct bpf_iter_aux_info *aux) +{ + struct bpf_unix_iter_state *iter = priv_data; + int err; + + err = bpf_iter_init_seq_net(priv_data, aux); + if (err) + return err; + + err = bpf_iter_unix_realloc_batch(iter, INIT_BATCH_SZ); + if (err) { + bpf_iter_fini_seq_net(priv_data); + return err; + } + + return 0; +} + +static void bpf_iter_fini_unix(void *priv_data) +{ + struct bpf_unix_iter_state *iter = priv_data; + + bpf_iter_fini_seq_net(priv_data); + kvfree(iter->batch); +} + static const struct bpf_iter_seq_info unix_seq_info = { .seq_ops = &bpf_iter_unix_seq_ops, - .init_seq_private = bpf_iter_init_seq_net, - .fini_seq_private = bpf_iter_fini_seq_net, - .seq_priv_size = sizeof(struct seq_net_private), + .init_seq_private = bpf_iter_init_unix, + .fini_seq_private = bpf_iter_fini_unix, + .seq_priv_size = sizeof(struct bpf_unix_iter_state), }; static struct bpf_iter_reg unix_reg_info = {