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Message-Id: <1461773902-13528-6-git-send-email-nikolay@cumulusnetworks.com>
Date: Wed, 27 Apr 2016 18:18:20 +0200
From: Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
To: netdev@...r.kernel.org
Cc: roopa@...ulusnetworks.com, davem@...emloft.net,
stephen@...workplumber.org, jhs@...atatu.com,
Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
Subject: [PATCH net-next 5/7] bridge: vlan: RCUify pvid
Make pvid a pointer to a vlan struct and RCUify the access to it. Vlans
are already RCU-protected so the pvid vlan entry cannot disappear
without being initialized to NULL and going through a grace period first.
This change is necessary for the upcoming vlan counters and also would
serve to later move to vlan passing via a pointer instead of id.
Signed-off-by: Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
---
net/bridge/br_netlink.c | 23 ++++++++++-----------
net/bridge/br_private.h | 16 +--------------
net/bridge/br_vlan.c | 54 +++++++++++++++++++++++--------------------------
3 files changed, 37 insertions(+), 56 deletions(-)
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index e9c635eae24d..f33d95b0f5d3 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -24,22 +24,22 @@
static int __get_num_vlan_infos(struct net_bridge_vlan_group *vg,
u32 filter_mask)
{
- struct net_bridge_vlan *v;
+ struct net_bridge_vlan *v, *pvid;
u16 vid_range_start = 0, vid_range_end = 0, vid_range_flags = 0;
- u16 flags, pvid;
int num_vlans = 0;
+ u16 flags;
if (!(filter_mask & RTEXT_FILTER_BRVLAN_COMPRESSED))
return 0;
- pvid = br_get_pvid(vg);
+ pvid = rcu_dereference(vg->pvid);
/* Count number of vlan infos */
list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
flags = 0;
/* only a context, bridge vlan not activated */
if (!br_vlan_should_use(v))
continue;
- if (v->vid == pvid)
+ if (v == pvid)
flags |= BRIDGE_VLAN_INFO_PVID;
if (v->flags & BRIDGE_VLAN_INFO_UNTAGGED)
@@ -243,21 +243,21 @@ nla_put_failure:
static int br_fill_ifvlaninfo_compressed(struct sk_buff *skb,
struct net_bridge_vlan_group *vg)
{
- struct net_bridge_vlan *v;
+ struct net_bridge_vlan *v, *pvid;
u16 vid_range_start = 0, vid_range_end = 0, vid_range_flags = 0;
- u16 flags, pvid;
int err = 0;
+ u16 flags;
/* Pack IFLA_BRIDGE_VLAN_INFO's for every vlan
* and mark vlan info with begin and end flags
* if vlaninfo represents a range
*/
- pvid = br_get_pvid(vg);
+ pvid = rcu_dereference(vg->pvid);
list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
flags = 0;
if (!br_vlan_should_use(v))
continue;
- if (v->vid == pvid)
+ if (v == pvid)
flags |= BRIDGE_VLAN_INFO_PVID;
if (v->flags & BRIDGE_VLAN_INFO_UNTAGGED)
@@ -298,18 +298,17 @@ initvars:
static int br_fill_ifvlaninfo(struct sk_buff *skb,
struct net_bridge_vlan_group *vg)
{
+ struct net_bridge_vlan *v, *pvid;
struct bridge_vlan_info vinfo;
- struct net_bridge_vlan *v;
- u16 pvid;
- pvid = br_get_pvid(vg);
+ pvid = rcu_dereference(vg->pvid);
list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
if (!br_vlan_should_use(v))
continue;
vinfo.vid = v->vid;
vinfo.flags = 0;
- if (v->vid == pvid)
+ if (v == pvid)
vinfo.flags |= BRIDGE_VLAN_INFO_PVID;
if (v->flags & BRIDGE_VLAN_INFO_UNTAGGED)
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 1b5d145dfcbf..50d70b5eb307 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -130,8 +130,8 @@ struct net_bridge_vlan {
struct net_bridge_vlan_group {
struct rhashtable vlan_hash;
struct list_head vlan_list;
+ struct net_bridge_vlan __rcu *pvid;
u16 num_vlans;
- u16 pvid;
};
struct net_bridge_fdb_entry
@@ -741,15 +741,6 @@ static inline int br_vlan_get_tag(const struct sk_buff *skb, u16 *vid)
return err;
}
-static inline u16 br_get_pvid(const struct net_bridge_vlan_group *vg)
-{
- if (!vg)
- return 0;
-
- smp_rmb();
- return vg->pvid;
-}
-
static inline int br_vlan_enabled(struct net_bridge *br)
{
return br->vlan_enabled;
@@ -835,11 +826,6 @@ static inline u16 br_vlan_get_tag(const struct sk_buff *skb, u16 *tag)
return 0;
}
-static inline u16 br_get_pvid(const struct net_bridge_vlan_group *vg)
-{
- return 0;
-}
-
static inline int br_vlan_enabled(struct net_bridge *br)
{
return 0;
diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index e001152d6ad1..4fab7665df8c 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -31,22 +31,11 @@ static struct net_bridge_vlan *br_vlan_lookup(struct rhashtable *tbl, u16 vid)
return rhashtable_lookup_fast(tbl, &vid, br_vlan_rht_params);
}
-static void __vlan_add_pvid(struct net_bridge_vlan_group *vg, u16 vid)
+/* __vlan_delete_pvid is just __vlan_set_pvid(vg, NULL) */
+static void __vlan_set_pvid(struct net_bridge_vlan_group *vg,
+ struct net_bridge_vlan *v)
{
- if (vg->pvid == vid)
- return;
-
- smp_wmb();
- vg->pvid = vid;
-}
-
-static void __vlan_delete_pvid(struct net_bridge_vlan_group *vg, u16 vid)
-{
- if (vg->pvid != vid)
- return;
-
- smp_wmb();
- vg->pvid = 0;
+ rcu_assign_pointer(vg->pvid, v);
}
static void __vlan_add_flags(struct net_bridge_vlan *v, u16 flags)
@@ -59,9 +48,9 @@ static void __vlan_add_flags(struct net_bridge_vlan *v, u16 flags)
vg = nbp_vlan_group(v->port);
if (flags & BRIDGE_VLAN_INFO_PVID)
- __vlan_add_pvid(vg, v->vid);
- else
- __vlan_delete_pvid(vg, v->vid);
+ __vlan_set_pvid(vg, v);
+ else if (rtnl_dereference(vg->pvid) == v)
+ __vlan_set_pvid(vg, NULL);
if (flags & BRIDGE_VLAN_INFO_UNTAGGED)
v->flags |= BRIDGE_VLAN_INFO_UNTAGGED;
@@ -285,7 +274,9 @@ static int __vlan_del(struct net_bridge_vlan *v)
masterv = v->brvlan;
}
- __vlan_delete_pvid(vg, v->vid);
+ if (rtnl_dereference(vg->pvid) == v)
+ __vlan_set_pvid(vg, NULL);
+
if (p) {
err = __vlan_vid_del(p->dev, p->br, v->vid);
if (err)
@@ -320,7 +311,7 @@ static void __vlan_flush(struct net_bridge_vlan_group *vg)
{
struct net_bridge_vlan *vlan, *tmp;
- __vlan_delete_pvid(vg, vg->pvid);
+ __vlan_set_pvid(vg, NULL);
list_for_each_entry_safe(vlan, tmp, &vg->vlan_list, vlist)
__vlan_del(vlan);
}
@@ -404,29 +395,29 @@ static bool __allowed_ingress(struct net_bridge_vlan_group *vg, __be16 proto,
}
if (!*vid) {
- u16 pvid = br_get_pvid(vg);
+ v = rcu_dereference(vg->pvid);
/* Frame had a tag with VID 0 or did not have a tag.
* See if pvid is set on this port. That tells us which
* vlan untagged or priority-tagged traffic belongs to.
*/
- if (!pvid)
+ if (!v)
goto drop;
/* PVID is set on this port. Any untagged or priority-tagged
* ingress frame is considered to belong to this vlan.
*/
- *vid = pvid;
+ *vid = v->vid;
if (likely(!tagged))
/* Untagged Frame. */
- __vlan_hwaccel_put_tag(skb, proto, pvid);
+ __vlan_hwaccel_put_tag(skb, proto, v->vid);
else
/* Priority-tagged Frame.
* At this point, We know that skb->vlan_tci had
* VLAN_TAG_PRESENT bit and its VID field was 0x000.
* We update only VID field and preserve PCP field.
*/
- skb->vlan_tci |= pvid;
+ skb->vlan_tci |= v->vid;
return true;
}
@@ -451,6 +442,9 @@ bool br_allowed_ingress(const struct net_bridge *br,
BR_INPUT_SKB_CB(skb)->vlan_filtered = false;
return true;
}
+ /* if there's no vlan_group, there's nothing to match against */
+ if (!vg)
+ return false;
return __allowed_ingress(vg, br->vlan_proto, skb, vid);
}
@@ -492,9 +486,11 @@ bool br_should_learn(struct net_bridge_port *p, struct sk_buff *skb, u16 *vid)
*vid = 0;
if (!*vid) {
- *vid = br_get_pvid(vg);
- if (!*vid)
+ struct net_bridge_vlan *v = rcu_dereference(vg->pvid);
+
+ if (!v)
return false;
+ *vid = v->vid;
return true;
}
@@ -713,9 +709,9 @@ int br_vlan_set_proto(struct net_bridge *br, unsigned long val)
static bool vlan_default_pvid(struct net_bridge_vlan_group *vg, u16 vid)
{
- struct net_bridge_vlan *v;
+ struct net_bridge_vlan *v = rtnl_dereference(vg->pvid);
- if (vid != vg->pvid)
+ if (v && vid != v->vid)
return false;
v = br_vlan_lookup(&vg->vlan_hash, vid);
--
2.4.11
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