From patchwork Mon Jun 10 22:34:51 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuniyuki Iwashima X-Patchwork-Id: 13692491 X-Patchwork-Delegate: kuba@kernel.org Received: from smtp-fw-80007.amazon.com (smtp-fw-80007.amazon.com [99.78.197.218]) (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 E091577107 for ; Mon, 10 Jun 2024 22:35:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=99.78.197.218 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718058951; cv=none; b=u2fLnklSI57DuvjE+hmb1ApaNiQlwKt8XCb0QHxhLVqp2vzxkkqpgigwANamsjV6LUeNkFQafzoGzXDszkcb0ZfFTJWUmKZz9VOPa/NYAi/uud0eLLzB32/hlpiBzfHxRF1zUC7SysuhsY5Fx8QrwknrF8L0IT91WoW3l1lXIZU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718058951; c=relaxed/simple; bh=gMp4aV4SCsbPm4EKU0tH039zYc/yruFPf70heRz5ySA=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=aXQ3Nh8/Yp3Q99s21vcw85/kGXs/VRsx7k960cw7Z7peET/RMyIXrYZs0nZagVDIZH+nQrFMDPYh1ZL5MlY9pkh/M5r1Tngm+qBF1sfn/bML5ZH8Xz2kzSY7AqXnsBmUiIwTyy+kQ45ssqHUgtZrLKTrV7KvLqXxQIJ1zyNzz3U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.co.jp; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=Cu4HxK8/; arc=none smtp.client-ip=99.78.197.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.co.jp Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="Cu4HxK8/" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1718058950; x=1749594950; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=euvermPs3H2QcOb2+dlyMMnaIjpyGx1RRSgxzgl9O1Q=; b=Cu4HxK8/93t/uRsjZluCTvEZCKU+hlwUJXYl+Uq+HHkUxaC8nFBMglHg DWvbEfLEVEuRdbrgcnQmcQCT/ZkSp9lLwwPrKdjpDArsp4l0nBXHueYct hz0XDdMiQDd14NsHCFjcW1KA4AgNwjvgE4q1NfqPADGuUFfeh+HQ+RaCt E=; X-IronPort-AV: E=Sophos;i="6.08,228,1712620800"; d="scan'208";a="302453710" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.25.36.210]) by smtp-border-fw-80007.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jun 2024 22:35:48 +0000 Received: from EX19MTAUWC001.ant.amazon.com [10.0.7.35:58069] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.51.69:2525] with esmtp (Farcaster) id da15b280-9a4d-44df-88df-04c55c62eb08; Mon, 10 Jun 2024 22:35:47 +0000 (UTC) X-Farcaster-Flow-ID: da15b280-9a4d-44df-88df-04c55c62eb08 Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX19MTAUWC001.ant.amazon.com (10.250.64.174) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.34; Mon, 10 Jun 2024 22:35:40 +0000 Received: from 88665a182662.ant.amazon.com.com (10.187.171.27) by EX19D004ANA001.ant.amazon.com (10.37.240.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.34; Mon, 10 Jun 2024 22:35:38 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni CC: Kent Overstreet , Kuniyuki Iwashima , Kuniyuki Iwashima , Subject: [PATCH v1 net-next 01/11] af_unix: Define locking order for unix_table_double_lock(). Date: Mon, 10 Jun 2024 15:34:51 -0700 Message-ID: <20240610223501.73191-2-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20240610223501.73191-1-kuniyu@amazon.com> References: <20240610223501.73191-1-kuniyu@amazon.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: EX19D036UWC001.ant.amazon.com (10.13.139.233) To EX19D004ANA001.ant.amazon.com (10.37.240.138) X-Patchwork-Delegate: kuba@kernel.org When created, AF_UNIX socket is put into net->unx.table.buckets[], and the hash is stored in sk->sk_hash. * unbound socket : 0 <= sk_hash <= UNIX_HASH_MOD When bind() is called, the socket could be moved to another bucket. * pathname socket : 0 <= sk_hash <= UNIX_HASH_MOD * abstract socket : UNIX_HASH_MOD + 1 <= sk_hash <= UNIX_HASH_MOD * 2 + 1 Then, we call unix_table_double_lock() which locks a single bucket or two. Let's define the order as unix_table_lock_cmp_fn() instead of using spin_lock_nested(). The locking is always done in ascending order of sk->sk_hash, which is the index of buckets/locks array allocated by kvmalloc_array(). sk_hash_A < sk_hash_B <=> &locks[sk_hash_A].dep_map < &locks[sk_hash_B].dep_map So, the relation of two sk->sk_hash can be derived from the addresses of dep_map in the array of locks. Signed-off-by: Kuniyuki Iwashima --- net/unix/af_unix.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 3821f8945b1e..b0a9891c0384 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -126,6 +126,13 @@ static spinlock_t bsd_socket_locks[UNIX_HASH_SIZE / 2]; * hash table is protected with spinlock. * each socket state is protected by separate spinlock. */ +#ifdef CONFIG_PROVE_LOCKING +static int unix_table_lock_cmp_fn(const struct lockdep_map *a, + const struct lockdep_map *b) +{ + return a < b ? -1 : 0; +} +#endif static unsigned int unix_unbound_hash(struct sock *sk) { @@ -168,7 +175,7 @@ static void unix_table_double_lock(struct net *net, swap(hash1, hash2); spin_lock(&net->unx.table.locks[hash1]); - spin_lock_nested(&net->unx.table.locks[hash2], SINGLE_DEPTH_NESTING); + spin_lock(&net->unx.table.locks[hash2]); } static void unix_table_double_unlock(struct net *net, @@ -3578,6 +3585,7 @@ static int __net_init unix_net_init(struct net *net) for (i = 0; i < UNIX_HASH_SIZE; i++) { spin_lock_init(&net->unx.table.locks[i]); + lock_set_cmp_fn(&net->unx.table.locks[i], unix_table_lock_cmp_fn, NULL); INIT_HLIST_HEAD(&net->unx.table.buckets[i]); }