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authorEric Dumazet <edumazet@google.com>2022-06-23 07:34:32 +0300
committerDavid S. Miller <davem@davemloft.net>2022-06-24 13:34:37 +0300
commitebc3197963fc42841b183d0280bd3f9f85f13c30 (patch)
tree7c91d003c63e3d304036322e892a9bc833c76bee /net/ipv4/ipmr.c
parent0a24c43f54b296629774b47a0763123f3c18db9b (diff)
downloadlinux-ebc3197963fc42841b183d0280bd3f9f85f13c30.tar.xz
ipmr: add rcu protection over (struct vif_device)->dev
We will soon use RCU instead of rwlock in ipmr & ip6mr This preliminary patch adds proper rcu verbs to read/write (struct vif_device)->dev Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ipmr.c')
-rw-r--r--net/ipv4/ipmr.c65
1 files changed, 38 insertions, 27 deletions
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 8324e541d193..10371a9e78fc 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -79,6 +79,12 @@ struct ipmr_result {
static DEFINE_RWLOCK(mrt_lock);
+static struct net_device *vif_dev_read(const struct vif_device *vif)
+{
+ return rcu_dereference_check(vif->dev,
+ lockdep_is_held(&mrt_lock));
+}
+
/* Multicast router control variables */
/* Special spinlock for queue of unresolved entries */
@@ -586,7 +592,7 @@ static int __pim_rcv(struct mr_table *mrt, struct sk_buff *skb,
read_lock(&mrt_lock);
if (mrt->mroute_reg_vif_num >= 0)
- reg_dev = mrt->vif_table[mrt->mroute_reg_vif_num].dev;
+ reg_dev = vif_dev_read(&mrt->vif_table[mrt->mroute_reg_vif_num]);
read_unlock(&mrt_lock);
if (!reg_dev)
@@ -614,10 +620,11 @@ static struct net_device *ipmr_reg_vif(struct net *net, struct mr_table *mrt)
static int call_ipmr_vif_entry_notifiers(struct net *net,
enum fib_event_type event_type,
struct vif_device *vif,
+ struct net_device *vif_dev,
vifi_t vif_index, u32 tb_id)
{
return mr_call_vif_notifiers(net, RTNL_FAMILY_IPMR, event_type,
- vif, vif_index, tb_id,
+ vif, vif_dev, vif_index, tb_id,
&net->ipv4.ipmr_seq);
}
@@ -649,18 +656,14 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify,
v = &mrt->vif_table[vifi];
- if (VIF_EXISTS(mrt, vifi))
- call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_DEL, v, vifi,
- mrt->id);
+ dev = rtnl_dereference(v->dev);
+ if (!dev)
+ return -EADDRNOTAVAIL;
write_lock_bh(&mrt_lock);
- dev = v->dev;
- v->dev = NULL;
-
- if (!dev) {
- write_unlock_bh(&mrt_lock);
- return -EADDRNOTAVAIL;
- }
+ call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_DEL, v, dev,
+ vifi, mrt->id);
+ RCU_INIT_POINTER(v->dev, NULL);
if (vifi == mrt->mroute_reg_vif_num)
mrt->mroute_reg_vif_num = -1;
@@ -890,14 +893,15 @@ static int vif_add(struct net *net, struct mr_table *mrt,
/* And finish update writing critical data */
write_lock_bh(&mrt_lock);
- v->dev = dev;
+ rcu_assign_pointer(v->dev, dev);
netdev_tracker_alloc(dev, &v->dev_tracker, GFP_ATOMIC);
if (v->flags & VIFF_REGISTER)
mrt->mroute_reg_vif_num = vifi;
if (vifi+1 > mrt->maxvif)
mrt->maxvif = vifi+1;
write_unlock_bh(&mrt_lock);
- call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, vifi, mrt->id);
+ call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, dev,
+ vifi, mrt->id);
return 0;
}
@@ -1726,7 +1730,7 @@ static int ipmr_device_event(struct notifier_block *this, unsigned long event, v
ipmr_for_each_table(mrt, net) {
v = &mrt->vif_table[0];
for (ct = 0; ct < mrt->maxvif; ct++, v++) {
- if (v->dev == dev)
+ if (rcu_access_pointer(v->dev) == dev)
vif_delete(mrt, ct, 1, NULL);
}
}
@@ -1811,19 +1815,21 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
{
const struct iphdr *iph = ip_hdr(skb);
struct vif_device *vif = &mrt->vif_table[vifi];
+ struct net_device *vif_dev;
struct net_device *dev;
struct rtable *rt;
struct flowi4 fl4;
int encap = 0;
- if (!vif->dev)
+ vif_dev = vif_dev_read(vif);
+ if (!vif_dev)
goto out_free;
if (vif->flags & VIFF_REGISTER) {
vif->pkt_out++;
vif->bytes_out += skb->len;
- vif->dev->stats.tx_bytes += skb->len;
- vif->dev->stats.tx_packets++;
+ vif_dev->stats.tx_bytes += skb->len;
+ vif_dev->stats.tx_packets++;
ipmr_cache_report(mrt, skb, vifi, IGMPMSG_WHOLEPKT);
goto out_free;
}
@@ -1881,8 +1887,8 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
if (vif->flags & VIFF_TUNNEL) {
ip_encap(net, skb, vif->local, vif->remote);
/* FIXME: extra output firewall step used to be here. --RR */
- vif->dev->stats.tx_packets++;
- vif->dev->stats.tx_bytes += skb->len;
+ vif_dev->stats.tx_packets++;
+ vif_dev->stats.tx_bytes += skb->len;
}
IPCB(skb)->flags |= IPSKB_FORWARDED;
@@ -1911,7 +1917,7 @@ static int ipmr_find_vif(struct mr_table *mrt, struct net_device *dev)
int ct;
for (ct = mrt->maxvif-1; ct >= 0; ct--) {
- if (mrt->vif_table[ct].dev == dev)
+ if (rcu_access_pointer(mrt->vif_table[ct].dev) == dev)
break;
}
return ct;
@@ -1944,7 +1950,7 @@ static void ip_mr_forward(struct net *net, struct mr_table *mrt,
}
/* Wrong interface: drop packet and (maybe) send PIM assert. */
- if (mrt->vif_table[vif].dev != dev) {
+ if (rcu_access_pointer(mrt->vif_table[vif].dev) != dev) {
if (rt_is_output_route(skb_rtable(skb))) {
/* It is our own packet, looped back.
* Very complicated situation...
@@ -2744,18 +2750,21 @@ static bool ipmr_fill_table(struct mr_table *mrt, struct sk_buff *skb)
static bool ipmr_fill_vif(struct mr_table *mrt, u32 vifid, struct sk_buff *skb)
{
+ struct net_device *vif_dev;
struct nlattr *vif_nest;
struct vif_device *vif;
+ vif = &mrt->vif_table[vifid];
+ vif_dev = vif_dev_read(vif);
/* if the VIF doesn't exist just continue */
- if (!VIF_EXISTS(mrt, vifid))
+ if (!vif_dev)
return true;
- vif = &mrt->vif_table[vifid];
vif_nest = nla_nest_start_noflag(skb, IPMRA_VIF);
if (!vif_nest)
return false;
- if (nla_put_u32(skb, IPMRA_VIFA_IFINDEX, vif->dev->ifindex) ||
+
+ if (nla_put_u32(skb, IPMRA_VIFA_IFINDEX, vif_dev->ifindex) ||
nla_put_u32(skb, IPMRA_VIFA_VIF_ID, vifid) ||
nla_put_u16(skb, IPMRA_VIFA_FLAGS, vif->flags) ||
nla_put_u64_64bit(skb, IPMRA_VIFA_BYTES_IN, vif->bytes_in,
@@ -2919,9 +2928,11 @@ static int ipmr_vif_seq_show(struct seq_file *seq, void *v)
"Interface BytesIn PktsIn BytesOut PktsOut Flags Local Remote\n");
} else {
const struct vif_device *vif = v;
- const char *name = vif->dev ?
- vif->dev->name : "none";
+ const struct net_device *vif_dev;
+ const char *name;
+ vif_dev = vif_dev_read(vif);
+ name = vif_dev ? vif_dev->name : "none";
seq_printf(seq,
"%2td %-10s %8ld %7ld %8ld %7ld %05X %08X %08X\n",
vif - mrt->vif_table,