From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 64C3B18A92F for ; Sat, 9 May 2026 00:49:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778287751; cv=none; b=UcSa9/NAWmDYYx3dvcWSgsH6phmBoHPyqaK9nJ3/ngKjTyhlEVCXAX0R2fk6aesvs6OvyKlEKTvtt4e1Q0mzgW99lAmEscDDkyC8GjXxDuCH0fMMjO8OO22UqEkpCa9X7aqZ29TNYccTJl/V1UAkag+AXpX+8yTFp3uxRUL5V9Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778287751; c=relaxed/simple; bh=je0QOvlYju3v6GKYGtVPDezMHi47SPorcg+YF1dU168=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ogzLWF4WQz5nRc2CbX4i150mGuEw+HJAfGVHXU37olN9DHCFLU8EWMbzCSgT3QbFgdtaIJhtrQJAFX5D8lfDCPKLsjEeS9YNi6m70Jvb8mjCwDWNe8ZoGaTXfIsFihxmTer8DIhvaW9hkr6kokok7Lk6eTJ9u/gBu5pSZDAU0V0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VqBf0Cr9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VqBf0Cr9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F5B2C2BCB0; Sat, 9 May 2026 00:49:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778287751; bh=je0QOvlYju3v6GKYGtVPDezMHi47SPorcg+YF1dU168=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VqBf0Cr9e50+xj+HUN5JJYYlcXFTRhbtM4aYzmhnS7K5SCbz9jUW9g5eAYL3Oi/5s cs9904XorSk4IhwYG8vp18c/VlJ+gHVhBedFTfX11U2uUDMM2V8Np6XWJvBT6jVH0u mooG45nhv2fD3prYUkGi3Z0LrCJERj0vN23SC7wK4Bx4lQx8vNL96kxiBp87FecW7o tEbwjgITVosGFQUR2XBGNJSfsBU44j4DU78PsxOJZYImmRfdQRvg40rWdifCnzVbb+ sdP5YDSicyedWdOQkkQaCK4YcTh1KSaba1Lufb6pnFEZSCu/QpBjDxGphQUt7R8JQo QLV0VlhqC0zbQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Longxuan Yu , Yuan Tan , Ren Wei , Paolo Abeni , Sasha Levin Subject: [PATCH 7.0.y 1/2] 8021q: use RCU for egress QoS mappings Date: Fri, 8 May 2026 20:49:06 -0400 Message-ID: <20260509004907.2449764-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026050408-speak-purging-28a1@gregkh> References: <2026050408-speak-purging-28a1@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Longxuan Yu [ Upstream commit fc69decc811b155a0ed8eef17ee940f28c4f6dbc ] The TX fast path and reporting paths walk egress QoS mappings without RTNL. Convert the mapping lists to RCU-protected pointers, use RCU reader annotations in readers, and defer freeing mapping nodes with an embedded rcu_head. This prepares the egress QoS mapping code for safe removal of mapping nodes in a follow-up change while preserving the current behavior. Co-developed-by: Yuan Tan Signed-off-by: Yuan Tan Signed-off-by: Longxuan Yu Signed-off-by: Ren Wei Link: https://patch.msgid.link/9136768189f8c6d3f824f476c62d2fa1111688e8.1776647968.git.yuantan098@gmail.com Signed-off-by: Paolo Abeni Stable-dep-of: 7dddc74af369 ("8021q: delete cleared egress QoS mappings") Signed-off-by: Sasha Levin --- include/linux/if_vlan.h | 25 ++++++++++++++++--------- net/8021q/vlan_dev.c | 31 ++++++++++++++++--------------- net/8021q/vlan_netlink.c | 10 ++++++---- net/8021q/vlanproc.c | 12 ++++++++---- 4 files changed, 46 insertions(+), 32 deletions(-) diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h index e6272f9c5e42c..20cc16ea4e5ab 100644 --- a/include/linux/if_vlan.h +++ b/include/linux/if_vlan.h @@ -147,11 +147,13 @@ extern __be16 vlan_dev_vlan_proto(const struct net_device *dev); * @priority: skb priority * @vlan_qos: vlan priority: (skb->priority << 13) & 0xE000 * @next: pointer to next struct + * @rcu: used for deferred freeing of mapping nodes */ struct vlan_priority_tci_mapping { u32 priority; u16 vlan_qos; - struct vlan_priority_tci_mapping *next; + struct vlan_priority_tci_mapping __rcu *next; + struct rcu_head rcu; }; struct proc_dir_entry; @@ -177,7 +179,7 @@ struct vlan_dev_priv { unsigned int nr_ingress_mappings; u32 ingress_priority_map[8]; unsigned int nr_egress_mappings; - struct vlan_priority_tci_mapping *egress_priority_map[16]; + struct vlan_priority_tci_mapping __rcu *egress_priority_map[16]; __be16 vlan_proto; u16 vlan_id; @@ -209,19 +211,24 @@ static inline u16 vlan_dev_get_egress_qos_mask(struct net_device *dev, u32 skprio) { struct vlan_priority_tci_mapping *mp; + u16 vlan_qos = 0; - smp_rmb(); /* coupled with smp_wmb() in vlan_dev_set_egress_priority() */ + rcu_read_lock(); - mp = vlan_dev_priv(dev)->egress_priority_map[(skprio & 0xF)]; + mp = rcu_dereference(vlan_dev_priv(dev)->egress_priority_map[skprio & 0xF]); while (mp) { if (mp->priority == skprio) { - return mp->vlan_qos; /* This should already be shifted - * to mask correctly with the - * VLAN's TCI */ + vlan_qos = READ_ONCE(mp->vlan_qos); + break; } - mp = mp->next; + mp = rcu_dereference(mp->next); } - return 0; + rcu_read_unlock(); + + /* This should already be shifted to mask correctly with + * the VLAN's TCI. + */ + return vlan_qos; } extern bool vlan_do_receive(struct sk_buff **skb); diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c index c40f7d5c4fca5..a5340932b657a 100644 --- a/net/8021q/vlan_dev.c +++ b/net/8021q/vlan_dev.c @@ -172,39 +172,34 @@ int vlan_dev_set_egress_priority(const struct net_device *dev, u32 skb_prio, u16 vlan_prio) { struct vlan_dev_priv *vlan = vlan_dev_priv(dev); - struct vlan_priority_tci_mapping *mp = NULL; + struct vlan_priority_tci_mapping *mp; struct vlan_priority_tci_mapping *np; + u32 bucket = skb_prio & 0xF; u32 vlan_qos = (vlan_prio << VLAN_PRIO_SHIFT) & VLAN_PRIO_MASK; /* See if a priority mapping exists.. */ - mp = vlan->egress_priority_map[skb_prio & 0xF]; + mp = rtnl_dereference(vlan->egress_priority_map[bucket]); while (mp) { if (mp->priority == skb_prio) { if (mp->vlan_qos && !vlan_qos) vlan->nr_egress_mappings--; else if (!mp->vlan_qos && vlan_qos) vlan->nr_egress_mappings++; - mp->vlan_qos = vlan_qos; + WRITE_ONCE(mp->vlan_qos, vlan_qos); return 0; } - mp = mp->next; + mp = rtnl_dereference(mp->next); } /* Create a new mapping then. */ - mp = vlan->egress_priority_map[skb_prio & 0xF]; np = kmalloc_obj(struct vlan_priority_tci_mapping); if (!np) return -ENOBUFS; - np->next = mp; np->priority = skb_prio; np->vlan_qos = vlan_qos; - /* Before inserting this element in hash table, make sure all its fields - * are committed to memory. - * coupled with smp_rmb() in vlan_dev_get_egress_qos_mask() - */ - smp_wmb(); - vlan->egress_priority_map[skb_prio & 0xF] = np; + RCU_INIT_POINTER(np->next, rtnl_dereference(vlan->egress_priority_map[bucket])); + rcu_assign_pointer(vlan->egress_priority_map[bucket], np); if (vlan_qos) vlan->nr_egress_mappings++; return 0; @@ -604,11 +599,17 @@ void vlan_dev_free_egress_priority(const struct net_device *dev) int i; for (i = 0; i < ARRAY_SIZE(vlan->egress_priority_map); i++) { - while ((pm = vlan->egress_priority_map[i]) != NULL) { - vlan->egress_priority_map[i] = pm->next; - kfree(pm); + pm = rtnl_dereference(vlan->egress_priority_map[i]); + RCU_INIT_POINTER(vlan->egress_priority_map[i], NULL); + while (pm) { + struct vlan_priority_tci_mapping *next; + + next = rtnl_dereference(pm->next); + kfree_rcu(pm, rcu); + pm = next; } } + vlan->nr_egress_mappings = 0; } static void vlan_dev_uninit(struct net_device *dev) diff --git a/net/8021q/vlan_netlink.c b/net/8021q/vlan_netlink.c index a000b1ef05206..a5b16833e2cee 100644 --- a/net/8021q/vlan_netlink.c +++ b/net/8021q/vlan_netlink.c @@ -260,13 +260,15 @@ static int vlan_fill_info(struct sk_buff *skb, const struct net_device *dev) goto nla_put_failure; for (i = 0; i < ARRAY_SIZE(vlan->egress_priority_map); i++) { - for (pm = vlan->egress_priority_map[i]; pm; - pm = pm->next) { - if (!pm->vlan_qos) + for (pm = rcu_dereference_rtnl(vlan->egress_priority_map[i]); pm; + pm = rcu_dereference_rtnl(pm->next)) { + u16 vlan_qos = READ_ONCE(pm->vlan_qos); + + if (!vlan_qos) continue; m.from = pm->priority; - m.to = (pm->vlan_qos >> 13) & 0x7; + m.to = (vlan_qos >> 13) & 0x7; if (nla_put(skb, IFLA_VLAN_QOS_MAPPING, sizeof(m), &m)) goto nla_put_failure; diff --git a/net/8021q/vlanproc.c b/net/8021q/vlanproc.c index fa67374bda494..0e424e0895b7e 100644 --- a/net/8021q/vlanproc.c +++ b/net/8021q/vlanproc.c @@ -262,15 +262,19 @@ static int vlandev_seq_show(struct seq_file *seq, void *offset) vlan->ingress_priority_map[7]); seq_printf(seq, " EGRESS priority mappings: "); + rcu_read_lock(); for (i = 0; i < 16; i++) { - const struct vlan_priority_tci_mapping *mp - = vlan->egress_priority_map[i]; + const struct vlan_priority_tci_mapping *mp = + rcu_dereference(vlan->egress_priority_map[i]); while (mp) { + u16 vlan_qos = READ_ONCE(mp->vlan_qos); + seq_printf(seq, "%u:%d ", - mp->priority, ((mp->vlan_qos >> 13) & 0x7)); - mp = mp->next; + mp->priority, ((vlan_qos >> 13) & 0x7)); + mp = rcu_dereference(mp->next); } } + rcu_read_unlock(); seq_puts(seq, "\n"); return 0; -- 2.53.0