From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f202.google.com (mail-qk1-f202.google.com [209.85.222.202]) (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 D946D3F54C3 for ; Wed, 3 Jun 2026 06:20:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780467655; cv=none; b=Pu9/whjsRD1+2G9pK7dJjvkXOApiMJPIbfxF4idlGNgtrm34WjuP37MR4XVsEKIRx3xEN7X/NtgCRU7DsazkYVaXprVkAG5toRWEZN5NlvxuQCQHr1QTXCdl7ZkS+FLLH7UZHXlgdBXNttYLE758uLLY/ZS20Cyl43ZpwgEhGV8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780467655; c=relaxed/simple; bh=d6n7Vl1jTydvct7TlwCBMQ/CXDzuo/bCLpen20DWzF8=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Hfi2E+jVzqoFlxKoGhVTvgD9IUqKYMWXLmFlPxbj25v4E2kbR6xTP/BeCtVaaSm6gufKBhgwpoN6pyCqZlEaig1XSHw1XtwECHr32Nf3IchHaCsZs6aBpIis8ZuORlOntEJNEsMmD6luvQoozqG2Wruw+IIRjrNuMpI6U00o1pw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=hcg+UMcD; arc=none smtp.client-ip=209.85.222.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="hcg+UMcD" Received: by mail-qk1-f202.google.com with SMTP id af79cd13be357-9157ae36434so273111885a.0 for ; Tue, 02 Jun 2026 23:20:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1780467653; x=1781072453; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=h5p5wR1WAxrF2smYm/DJM232M/Fl2LwG4jjSzzxq6EY=; b=hcg+UMcDsyQkGe9sG7nn5I+tIDx2VyG3vEfwUI6kAwoVVJco3RtKBKQS+vh5Z+iSnx +wj87gtW8ANbtZm3wnHEV9tHcPETH5gEdZMXCMQlvnmVDTjZrg+R9q8LzuRiQVjtEwEG HMWCcYINjTMR5TjiWBfoBZnd1kk6hhUBvbP81cBQxg3ppFEDGipn/W3o0vLrBoOXAy9W nCUQJR7by8QupJrkO6ERAd0XWIlCBCxOtPdalITjhvtcxQG5PiqTPS65wga+aDvL8kKX qWj2+zesElJuSXA09TKytCfl1Yy4x6WGXmcOzDmijevL3UDV8KYhBFBHkplJvkivjWXZ v69w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780467653; x=1781072453; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=h5p5wR1WAxrF2smYm/DJM232M/Fl2LwG4jjSzzxq6EY=; b=W20Xsf82im3xnUB4J6yU155DKVcns1K8wIfLxCXMePJmIrRVjyNsD9hFydrRlbvtE4 sXZzw80ZvPp+INDdaklJHsPoWdFEJldyciDnTIThdi1VXPdcW4XBEx35itbcx+aDAhZg X2+sJtFhgWSETFMAAxLnFHDpnAPsXNIYnnAsiR/3qIMp7ywfmUw0omwDo7UcLevkOst5 7x24EEw+IMClyKX5ZI6d4sIDJxjQSak58tN8xuLH+uPYjN9oq1BdeDXLJ/uwB8lZ1BU6 Hcmb7RaHVGYBAWNzZdNPp0QN+7xvsS7twhGIjt4sFOdG4pfTIBFOEemwrXg9RlJRmlIK LSdw== X-Forwarded-Encrypted: i=1; AFNElJ+uPgwD8uFnCt5q+XUT026NV4+/sAuLKR4SP9xO+T9SN656aVa0trI6m/XN0Dnn+UnU3xc6NfE=@vger.kernel.org X-Gm-Message-State: AOJu0YxeP0OViG2+3ilJod43Ghf5p6VIzp91MQPAvP/RMYCbDwrhhVCz cTWfWTQXmYVW7y3NvRV9QBgWxPuEdkbJBPt2qmPKSw6NRQzlkIq7X+JKTx07NTrSPD97xb9SnfG 98ltagqhtccV5bA== X-Received: from qkbp5.prod.google.com ([2002:a05:620a:6f45:b0:915:7ded:9f6d]) (user=edumazet job=prod-delivery.src-stubby-dispatcher) by 2002:a05:620a:28c9:b0:8d7:cf69:3bf5 with SMTP id af79cd13be357-9158a68d218mr349345185a.14.1780467652726; Tue, 02 Jun 2026 23:20:52 -0700 (PDT) Date: Wed, 3 Jun 2026 06:20:37 +0000 In-Reply-To: <20260603062043.3911278-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260603062043.3911278-1-edumazet@google.com> X-Mailer: git-send-email 2.54.0.1013.g208068f2d8-goog Message-ID: <20260603062043.3911278-6-edumazet@google.com> Subject: [PATCH v2 net-next 05/11] bridge: provide lockless access to p->path_cost From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Ido Schimmel , Nikolay Aleksandrov , netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet Content-Type: text/plain; charset="UTF-8" Add READ_ONCE()/WRITE_ONCE() annotations around p->path_cost. This is needed at least for sysfs show_path_cost(), BRCTL_GET_PORT_INFO and upcoming RTNL avoidance in "ip link" dumps (cf br_port_fill_attrs()). Signed-off-by: Eric Dumazet --- net/bridge/br_if.c | 2 +- net/bridge/br_ioctl.c | 2 +- net/bridge/br_netlink.c | 2 +- net/bridge/br_stp.c | 17 +++++++++++------ net/bridge/br_stp_if.c | 2 +- net/bridge/br_sysfs_if.c | 2 +- 6 files changed, 16 insertions(+), 11 deletions(-) diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c index 0bd5cf925fa321b785e3578d6e99d8d7003fa89f..ab012e4762998fe8a133dd551e7f4f0efc6718c6 100644 --- a/net/bridge/br_if.c +++ b/net/bridge/br_if.c @@ -77,7 +77,7 @@ void br_port_carrier_check(struct net_bridge_port *p, bool *notified) if (!test_bit(BR_ADMIN_COST_BIT, &p->flags) && netif_running(dev) && netif_oper_up(dev)) - p->path_cost = port_cost(dev); + WRITE_ONCE(p->path_cost, port_cost(dev)); *notified = false; if (!netif_running(br->dev)) diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c index 766c43b327af830a80fba11c940ba34eb03c50c9..07cfcb821e27ebcb72901a365a3f06491f8b0bc3 100644 --- a/net/bridge/br_ioctl.c +++ b/net/bridge/br_ioctl.c @@ -259,7 +259,7 @@ int br_dev_siocdevprivate(struct net_device *dev, struct ifreq *rq, memcpy(&p.designated_bridge, &pt->designated_bridge, 8); p.port_id = pt->port_id; p.designated_port = pt->designated_port; - p.path_cost = pt->path_cost; + p.path_cost = READ_ONCE(pt->path_cost); p.designated_cost = pt->designated_cost; p.state = pt->state; p.top_change_ack = pt->topology_change_ack; diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c index a104b25c871d263e4b5701f1be05cb17fbfce28f..08718ebe282aa1d089a127cdc7c24fda5a0a38a5 100644 --- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -240,7 +240,7 @@ static int br_port_fill_attrs(struct sk_buff *skb, if (nla_put_u8(skb, IFLA_BRPORT_STATE, p->state) || nla_put_u16(skb, IFLA_BRPORT_PRIORITY, p->priority) || - nla_put_u32(skb, IFLA_BRPORT_COST, p->path_cost) || + nla_put_u32(skb, IFLA_BRPORT_COST, READ_ONCE(p->path_cost)) || nla_put_u8(skb, IFLA_BRPORT_MODE, mode) || nla_put_u8(skb, IFLA_BRPORT_GUARD, !!(p->flags & BR_BPDU_GUARD)) || nla_put_u8(skb, IFLA_BRPORT_PROTECT, diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c index 024210f95468308066827ac2ae71f68f99fa77f5..2d9d0823aa56b63a62ed51c49df54055294e82ad 100644 --- a/net/bridge/br_stp.c +++ b/net/bridge/br_stp.c @@ -102,8 +102,9 @@ struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no) static int br_should_become_root_port(const struct net_bridge_port *p, u16 root_port) { - struct net_bridge *br; + u32 p_path_cost, rp_path_cost; struct net_bridge_port *rp; + struct net_bridge *br; int t; br = p->br; @@ -125,11 +126,14 @@ static int br_should_become_root_port(const struct net_bridge_port *p, else if (t > 0) return 0; - if (p->designated_cost + p->path_cost < - rp->designated_cost + rp->path_cost) + p_path_cost = READ_ONCE(p->path_cost); + rp_path_cost = READ_ONCE(rp->path_cost); + + if (p->designated_cost + p_path_cost < + rp->designated_cost + rp_path_cost) return 1; - else if (p->designated_cost + p->path_cost > - rp->designated_cost + rp->path_cost) + else if (p->designated_cost + p_path_cost > + rp->designated_cost + rp_path_cost) return 0; t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8); @@ -187,7 +191,8 @@ static void br_root_selection(struct net_bridge *br) } else { p = br_get_port(br, root_port); br->designated_root = p->designated_root; - br->root_path_cost = p->designated_cost + p->path_cost; + br->root_path_cost = p->designated_cost + + READ_ONCE(p->path_cost); } } diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c index b29dc97b9ad8a5b5c56517d34fe426abd00e2ad6..e5d43492d2dcf0615ee984bc190d7ce2264aaab0 100644 --- a/net/bridge/br_stp_if.c +++ b/net/bridge/br_stp_if.c @@ -341,7 +341,7 @@ int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost) return -ERANGE; set_bit(BR_ADMIN_COST_BIT, &p->flags); - p->path_cost = path_cost; + WRITE_ONCE(p->path_cost, path_cost); br_configuration_update(p->br); br_port_state_selection(p->br); return 0; diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c index d6df81fa0d13fe7e732b69f881b947da2066d9ef..23574476d7f701080452777ab2c23a42b4defba4 100644 --- a/net/bridge/br_sysfs_if.c +++ b/net/bridge/br_sysfs_if.c @@ -83,7 +83,7 @@ static int store_flag(struct net_bridge_port *p, unsigned long v, static ssize_t show_path_cost(struct net_bridge_port *p, char *buf) { - return sysfs_emit(buf, "%d\n", p->path_cost); + return sysfs_emit(buf, "%d\n", READ_ONCE(p->path_cost)); } static int store_path_cost(struct net_bridge_port *p, unsigned long v) -- 2.54.0.1013.g208068f2d8-goog