From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f202.google.com (mail-qt1-f202.google.com [209.85.160.202]) (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 076E139182F for ; Wed, 1 Jul 2026 08:22:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782894144; cv=none; b=KkSufhIPDQ9oUCCaddyfNGw+ecCheUW9YKJJDKaxMuAiBbU4LgAwRQ9rymDiJVrRhXH7rien5BmJGmLFoZUDIws+PDIp94PUU9IXfp5sZZMy+P1Iet/Vj87toFHqzZBQn5xCtBBArdn4ruKb+kbPJ0w4t5YiyIVF3hxuhwVn32E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782894144; c=relaxed/simple; bh=tdp3p9Ya6jFblHE70d3MaHnBcVV3gQV0eq40vRAZfB8=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=VEezkg7yE54SsLX7VtzOkzq52WTAnVo33eqR456cxR6Bq+M9Y5AiI3dxulE5q6fP8qSwMuAhpIHpC3vKV5ZtL3xDZM/dmNOTaeFj6Th3kBt0cJ3IlmWzpa7s9CKj3U/Jdd7YpBMqBBlS8+yT0HcdFeqcRh0H507mr8STRD93PIA= 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=IZanTQ+u; arc=none smtp.client-ip=209.85.160.202 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="IZanTQ+u" Received: by mail-qt1-f202.google.com with SMTP id d75a77b69052e-51c20762d21so4386051cf.0 for ; Wed, 01 Jul 2026 01:22:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1782894140; x=1783498940; 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=rXRribuTUhkxLCWsUr25B2D8LvbDNvH+aRUNvKRnVG8=; b=IZanTQ+ubXNN/En3JQnwbkAv3ybDxh9pP5uFCbpzgzhJVIgZm+gswO8sOb1BJk5Kn0 z3mTU15XRLDVfsRvmzgB52MfISQ3TkYVovkExJaJVSaCIPDlK8JTHMZmXu32SCrGuoHc iZh1eKlQwgmvvJM9NSM09dw2u+B3CbiMtFOTyGcsIcDHQLkPYeE5f/I/h3Kkhs56pgCD gmrjah2/1HIMCuMWzXdijKfr8/MMXWqazIeuxUsvQhNxmGlwbBfLLNLKYEVgaxvCjeqP pYITfVppmROsJWmq5aJUGv5ZVOpB1ueqVaxex4Qk8T3D3cijuei6hXmyqzhZdWPqTQnj xCIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782894140; x=1783498940; 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=rXRribuTUhkxLCWsUr25B2D8LvbDNvH+aRUNvKRnVG8=; b=b2bHB3zIYlTCXl778srvBaA8He6BjE4L6pZbJSP/TyhSOUhwKjdujVwMkJ651TeFlE yQQ6eLV4wKrSpGIKUGDXzwRnmj4+bN0qmQGbAmlgLIOCQcOreyRuONSlXQsixAoILz9n uiLGXGQtoqdEcY5YCpH+hlIX6XJtDNGlUt7m1fMkgunZKbAHV4Ov4BWoK8CkjBUqfbFj Bf19r812fVYcAd8Cz6dozOWymhVO/ysVrC/nlv91gQsMvybVOOXz/IJJKkGxqMuQzIvX 6Ca3AeNRsH3CebN3WaSN2owLzEnlnMzfTSkfKgBAfWz+gNWavwn7klfnFfoQWOTdkdk+ Mv+Q== X-Forwarded-Encrypted: i=1; AFNElJ+ezGXXGi8gozdLrnrxg+//8C1AkpIoQSSmsDLoVAn10SuMyae/W5ljebCtkwJmA/u/kp651cI=@vger.kernel.org X-Gm-Message-State: AOJu0YyIEDUrC4tpNy+3mpRJ6xmC+GMHBiEZXNs+eQEiYzt0MgeDGQpJ v1179MXkbR5uZrXE9XnI6tD1Cv8paE8+jvZFwT61dbbH/gfxK4/r9leb0I3ngIK9eQKKnLxC0nB DrooQcSzCcu3X5w== X-Received: from qtbhe5.prod.google.com ([2002:a05:622a:6005:b0:517:8e0d:a114]) (user=edumazet job=prod-delivery.src-stubby-dispatcher) by 2002:a05:622a:2485:b0:51c:1ec5:d0f with SMTP id d75a77b69052e-51c26b005d2mr7683211cf.40.1782894139437; Wed, 01 Jul 2026 01:22:19 -0700 (PDT) Date: Wed, 1 Jul 2026 08:22:14 +0000 In-Reply-To: <20260701082214.2974946-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260701082214.2974946-1-edumazet@google.com> X-Mailer: git-send-email 2.55.0.rc0.799.gd6f94ed593-goog Message-ID: <20260701082214.2974946-3-edumazet@google.com> Subject: [PATCH net-next 2/2] macvlan: no longer rely on RTNL in macvlan_fill_info() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Kuniyuki Iwashima , netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet Content-Type: text/plain; charset="UTF-8" Add READ_ONCE()/WRITE_ONCE() annotations on vlan->mode, vlan->flags, vlan->bc_queue_len_req and port->bc_cutoff. Fill IFLA_MACVLAN_MACADDR_DATA nested attribute and compute on the fly the precise number of elements we put in it, to fill an accurate IFLA_MACVLAN_MACADDR_COUNT attribute as some user space applications could depend on its value and the attributes order. Signed-off-by: Eric Dumazet --- drivers/net/macvlan.c | 71 +++++++++++++++++++++++++++++-------------- 1 file changed, 48 insertions(+), 23 deletions(-) diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c index 8b69cc9b70f98d7991110f5eda76d58d5d96fa81..9a4bc99dbf53b5f2cd6345f0af899f56fdb3a46b 100644 --- a/drivers/net/macvlan.c +++ b/drivers/net/macvlan.c @@ -171,7 +171,7 @@ static int macvlan_hash_add_source(struct macvlan_dev *vlan, RCU_INIT_POINTER(entry->vlan, vlan); h = &port->vlan_source_hash[macvlan_eth_hash(addr)]; hlist_add_head_rcu(&entry->hlist, h); - vlan->macaddr_count++; + WRITE_ONCE(vlan->macaddr_count, vlan->macaddr_count + 1); return 0; } @@ -402,7 +402,7 @@ static void macvlan_flush_sources(struct macvlan_port *port, if (rcu_access_pointer(entry->vlan) == vlan) macvlan_hash_del_source(entry); - vlan->macaddr_count = 0; + WRITE_ONCE(vlan->macaddr_count, 0); } static void macvlan_forward_source_one(struct sk_buff *skb, @@ -874,7 +874,7 @@ static void update_port_bc_cutoff(struct macvlan_dev *vlan, int cutoff) if (vlan->port->bc_cutoff == cutoff) return; - vlan->port->bc_cutoff = cutoff; + WRITE_ONCE(vlan->port->bc_cutoff, cutoff); macvlan_recompute_bc_filter(vlan); } @@ -1427,7 +1427,7 @@ static int macvlan_changelink_sources(struct macvlan_dev *vlan, u32 mode, entry = macvlan_hash_lookup_source(vlan, addr); if (entry) { macvlan_hash_del_source(entry); - vlan->macaddr_count--; + WRITE_ONCE(vlan->macaddr_count, vlan->macaddr_count - 1); } } else if (mode == MACVLAN_MACADDR_FLUSH) { macvlan_flush_sources(vlan->port, vlan); @@ -1653,7 +1653,8 @@ static int macvlan_changelink(struct net_device *dev, } if (data && data[IFLA_MACVLAN_BC_QUEUE_LEN]) { - vlan->bc_queue_len_req = nla_get_u32(data[IFLA_MACVLAN_BC_QUEUE_LEN]); + WRITE_ONCE(vlan->bc_queue_len_req, + nla_get_u32(data[IFLA_MACVLAN_BC_QUEUE_LEN])); update_port_bc_queue_len(vlan->port); } @@ -1676,10 +1677,12 @@ static int macvlan_changelink(struct net_device *dev, static size_t macvlan_get_size_mac(const struct macvlan_dev *vlan) { - if (vlan->macaddr_count == 0) + unsigned int macaddr_count = READ_ONCE(vlan->macaddr_count); + + if (!macaddr_count) return 0; return nla_total_size(0) /* IFLA_MACVLAN_MACADDR_DATA */ - + vlan->macaddr_count * nla_total_size(sizeof(u8) * ETH_ALEN); + + macaddr_count * nla_total_size(sizeof(u8) * ETH_ALEN); } static size_t macvlan_get_size(const struct net_device *dev) @@ -1702,53 +1705,75 @@ static int macvlan_fill_info_macaddr(struct sk_buff *skb, const int i) { struct hlist_head *h = &vlan->port->vlan_source_hash[i]; - struct macvlan_source_entry *entry; + const struct macvlan_source_entry *entry; + int cnt = 0; - hlist_for_each_entry_rcu(entry, h, hlist, lockdep_rtnl_is_held()) { + hlist_for_each_entry_rcu(entry, h, hlist) { if (rcu_access_pointer(entry->vlan) != vlan) continue; if (nla_put(skb, IFLA_MACVLAN_MACADDR, ETH_ALEN, entry->addr)) - return 1; + return -EMSGSIZE; + cnt++; } - return 0; + return cnt; } static int macvlan_fill_info(struct sk_buff *skb, const struct net_device *dev) { - struct macvlan_dev *vlan = netdev_priv(dev); + const struct macvlan_dev *vlan = netdev_priv(dev); struct macvlan_port *port = vlan->port; - int i; - struct nlattr *nest; + unsigned int macaddr_count = 0; + struct nlattr *nest, *attr; + int bc_cutoff, cnt, i; - if (nla_put_u32(skb, IFLA_MACVLAN_MODE, vlan->mode)) + rcu_read_lock(); + if (nla_put_u32(skb, IFLA_MACVLAN_MODE, READ_ONCE(vlan->mode))) goto nla_put_failure; - if (nla_put_u16(skb, IFLA_MACVLAN_FLAGS, vlan->flags)) + + if (nla_put_u16(skb, IFLA_MACVLAN_FLAGS, READ_ONCE(vlan->flags))) goto nla_put_failure; - if (nla_put_u32(skb, IFLA_MACVLAN_MACADDR_COUNT, vlan->macaddr_count)) + + attr = nla_reserve(skb, IFLA_MACVLAN_MACADDR_COUNT, sizeof(u32)); + if (!attr) goto nla_put_failure; - if (vlan->macaddr_count > 0) { + + if (READ_ONCE(vlan->macaddr_count) > 0) { nest = nla_nest_start_noflag(skb, IFLA_MACVLAN_MACADDR_DATA); if (nest == NULL) goto nla_put_failure; for (i = 0; i < MACVLAN_HASH_SIZE; i++) { - if (macvlan_fill_info_macaddr(skb, vlan, i)) + cnt = macvlan_fill_info_macaddr(skb, vlan, i); + if (cnt < 0) goto nla_put_failure; + macaddr_count += cnt; } - nla_nest_end(skb, nest); + if (!macaddr_count) + nla_nest_cancel(skb, nest); + else if (nla_nest_end_safe(skb, nest) < 0) + goto nla_put_failure; } - if (nla_put_u32(skb, IFLA_MACVLAN_BC_QUEUE_LEN, vlan->bc_queue_len_req)) + *(u32 *)nla_data(attr) = macaddr_count; + + if (nla_put_u32(skb, IFLA_MACVLAN_BC_QUEUE_LEN, + READ_ONCE(vlan->bc_queue_len_req))) goto nla_put_failure; + if (nla_put_u32(skb, IFLA_MACVLAN_BC_QUEUE_LEN_USED, READ_ONCE(port->bc_queue_len_used))) goto nla_put_failure; - if (port->bc_cutoff != 1 && - nla_put_s32(skb, IFLA_MACVLAN_BC_CUTOFF, port->bc_cutoff)) + + bc_cutoff = READ_ONCE(port->bc_cutoff); + if (bc_cutoff != 1 && + nla_put_s32(skb, IFLA_MACVLAN_BC_CUTOFF, bc_cutoff)) goto nla_put_failure; + + rcu_read_unlock(); return 0; nla_put_failure: + rcu_read_unlock(); return -EMSGSIZE; } -- 2.55.0.rc0.799.gd6f94ed593-goog