From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f74.google.com (mail-qv1-f74.google.com [209.85.219.74]) (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 7ACA83E0245 for ; Thu, 21 May 2026 13:19:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779369570; cv=none; b=o2uebvNNpSgKc2VewOFR77FDFr4L/zmV3gl/pK/niQ1bp9gOxxj1QKE05X91JVvvpTpOfgSG5NKP6L7LWIM8RX3wd3ozE9x9GjkmWM9soCOeB31vGE55jiPxIrd6Dhpw1mVJtz0oY2lUp3w0c+DkUNtxOp8O9A5kqXL84jRghcI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779369570; c=relaxed/simple; bh=PluQH3UhbOhdSwwHy8khUeh620imreZyrckOxm7V8Ec=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=uNXiurH136/Jx/eBuWri8P78eY+HrVK9H+fDadubYvWoTstqdnIOuA/nq8NDYIfQCy0BH+m6llRsWeTLyWmkqlevdWR3waI9rqy7Jwpyyr+Sa0qKpVruheHFSC8rApgGMDD7gMEDqXClhwI//khthMMZ6c+sQx+hekYwVjNK698= 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=p47HNVjS; arc=none smtp.client-ip=209.85.219.74 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="p47HNVjS" Received: by mail-qv1-f74.google.com with SMTP id 6a1803df08f44-8b58065ea15so7912266d6.2 for ; Thu, 21 May 2026 06:19:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779369568; x=1779974368; 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=1jycji/ayAkcWwSIdIVlly3y8MakL6E3kLtFUixvHy0=; b=p47HNVjSKMP2AEBs424Yqb8TBeiysOMvPIUuBD7KtZ2dYszcKRVSqIbwAj73TbI4Il bRkxj64G5dgIsSBgJV4RuFIu8kcYz/Ep/jqSEDRSkD1Ft3pu30Zji6BZppBA4bhST9dz gpdp5iIs5M7Goy051iFhSSGxQ6RszxN0vB/CY+LZQhw2lqb5TJ9jMH5Mxp2Z9xnnkadQ xlzH7sI5IHPAby1xF1MWRtPjyQoz6kkT6am6KNlZmqiifeK4zp9qyttQQwwKaJxgRUXr E93bfhE8QPSB7T0mSDthmSzaJJd5FhkJEiroM7k0Q6JMB3urThGwssSVmDRl/cR+I7Sr gITQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779369568; x=1779974368; 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=1jycji/ayAkcWwSIdIVlly3y8MakL6E3kLtFUixvHy0=; b=HLc4bV6gn3WpuIXvrsIgiZanhP8I/x7gmzYq/LbjWx9wJ3NNTvDHzczf+MZNZIhQqx RPs7MrnbtqQN6Zk/e9tNGRrgNerHrQcZS8BS/heyIibyi6qSbyJUnFj5N80bVVh3nfEg 2ts3oZuT/X6g7UhLk9G0tKj1uz8DlzeNIgMgQgqOMeGHgfijnu7FnIQju4bwltbh88o1 13jDdJF8Owe6J2JjKpDEFSH9GXrYx4WIWQCpyHEUbE6ABqlzRQRfoNr9wgbNepU/YGMN PqFaaigFiH7mclZ0fswaDhrQuvHQ4ML/5Gw3dhsWitZ/qZfKMILRyjdAeAVWyuv1R9aX rbGg== X-Forwarded-Encrypted: i=1; AFNElJ8Qd767N3UvGh0ZAe/wAJ2l5RtVY2b0hvVefsPLjd0IGi5e+yHtUYtR44gni39lsMIMX8+X6GI=@vger.kernel.org X-Gm-Message-State: AOJu0YwlBoP+Y3ZhsOkYq6sPIVqgHVXR8L8xnHVQzZN0bQVcNvKBzOg8 BWaS7JOvGcwJ4+A7RRbjqwuNLSbNzedR+JPMD3V+3cSZ0rOCzpDyzGHM2L+lAeunqDEQMx2ndMm MhgjrhbltYcb5SQ== X-Received: from qvbdv5.prod.google.com ([2002:ad4:4ee5:0:b0:8ae:1b92:a1a3]) (user=edumazet job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6214:3a8c:b0:8ba:b3b3:971 with SMTP id 6a1803df08f44-8cc6e3846f1mr44106806d6.32.1779369568135; Thu, 21 May 2026 06:19:28 -0700 (PDT) Date: Thu, 21 May 2026 13:19:10 +0000 In-Reply-To: <20260521131916.3627204-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260521131916.3627204-1-edumazet@google.com> X-Mailer: git-send-email 2.54.0.669.g59709faab0-goog Message-ID: <20260521131916.3627204-6-edumazet@google.com> Subject: [PATCH 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 , netdev@vger.kernel.org, Ido Schimmel , Nikolay Aleksandrov , 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 | 12 +++++++----- net/bridge/br_stp_if.c | 2 +- net/bridge/br_sysfs_if.c | 2 +- 6 files changed, 12 insertions(+), 10 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 898326c201ef99a1dafda820bfbfe3d428ae2bd3..1b2fbb3a8f9b18ef6479bd3a0c63fe1e761df9a7 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..1367cd3ac4dd6a587d4a6471184453a14af6879c 100644 --- a/net/bridge/br_stp.c +++ b/net/bridge/br_stp.c @@ -125,11 +125,12 @@ 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) + t = p->designated_cost + READ_ONCE(p->path_cost) - + (rp->designated_cost + READ_ONCE(rp->path_cost)); + + if (t < 0) return 1; - else if (p->designated_cost + p->path_cost > - rp->designated_cost + rp->path_cost) + else if (t > 0) return 0; t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8); @@ -187,7 +188,8 @@ 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 1f57c36a7fc097d69cbb8bd7a9348c31be6611aa..0616036a3ce45d45ba817555362f1613f5f9d6cf 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 BRPORT_ATTR(path_cost, 0644, -- 2.54.0.669.g59709faab0-goog