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ip6mr: do not acquire mrt_lock in ioctl(SIOCGETMIFCNT_IN6)
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rcu_read_lock() protection is good enough.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Eric Dumazet authored and David S. Miller committed Jun 24, 2022
1 parent 6d08658 commit 638cf4a
Showing 1 changed file with 22 additions and 20 deletions.
42 changes: 22 additions & 20 deletions net/ipv6/ip6mr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1896,20 +1896,20 @@ int ip6mr_ioctl(struct sock *sk, int cmd, void __user *arg)
if (vr.mifi >= mrt->maxvif)
return -EINVAL;
vr.mifi = array_index_nospec(vr.mifi, mrt->maxvif);
read_lock(&mrt_lock);
rcu_read_lock();
vif = &mrt->vif_table[vr.mifi];
if (VIF_EXISTS(mrt, vr.mifi)) {
vr.icount = vif->pkt_in;
vr.ocount = vif->pkt_out;
vr.ibytes = vif->bytes_in;
vr.obytes = vif->bytes_out;
read_unlock(&mrt_lock);
vr.icount = READ_ONCE(vif->pkt_in);
vr.ocount = READ_ONCE(vif->pkt_out);
vr.ibytes = READ_ONCE(vif->bytes_in);
vr.obytes = READ_ONCE(vif->bytes_out);
rcu_read_unlock();

if (copy_to_user(arg, &vr, sizeof(vr)))
return -EFAULT;
return 0;
}
read_unlock(&mrt_lock);
rcu_read_unlock();
return -EADDRNOTAVAIL;
case SIOCGETSGCNT_IN6:
if (copy_from_user(&sr, arg, sizeof(sr)))
Expand Down Expand Up @@ -1971,20 +1971,20 @@ int ip6mr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
if (vr.mifi >= mrt->maxvif)
return -EINVAL;
vr.mifi = array_index_nospec(vr.mifi, mrt->maxvif);
read_lock(&mrt_lock);
rcu_read_lock();
vif = &mrt->vif_table[vr.mifi];
if (VIF_EXISTS(mrt, vr.mifi)) {
vr.icount = vif->pkt_in;
vr.ocount = vif->pkt_out;
vr.ibytes = vif->bytes_in;
vr.obytes = vif->bytes_out;
read_unlock(&mrt_lock);
vr.icount = READ_ONCE(vif->pkt_in);
vr.ocount = READ_ONCE(vif->pkt_out);
vr.ibytes = READ_ONCE(vif->bytes_in);
vr.obytes = READ_ONCE(vif->bytes_out);
rcu_read_unlock();

if (copy_to_user(arg, &vr, sizeof(vr)))
return -EFAULT;
return 0;
}
read_unlock(&mrt_lock);
rcu_read_unlock();
return -EADDRNOTAVAIL;
case SIOCGETSGCNT_IN6:
if (copy_from_user(&sr, arg, sizeof(sr)))
Expand Down Expand Up @@ -2038,8 +2038,8 @@ static int ip6mr_forward2(struct net *net, struct mr_table *mrt,

#ifdef CONFIG_IPV6_PIMSM_V2
if (vif->flags & MIFF_REGISTER) {
vif->pkt_out++;
vif->bytes_out += skb->len;
WRITE_ONCE(vif->pkt_out, vif->pkt_out + 1);
WRITE_ONCE(vif->bytes_out, vif->bytes_out + skb->len);
vif_dev->stats.tx_bytes += skb->len;
vif_dev->stats.tx_packets++;
rcu_read_lock();
Expand Down Expand Up @@ -2077,8 +2077,8 @@ static int ip6mr_forward2(struct net *net, struct mr_table *mrt,
* result in receiving multiple packets.
*/
skb->dev = vif_dev;
vif->pkt_out++;
vif->bytes_out += skb->len;
WRITE_ONCE(vif->pkt_out, vif->pkt_out + 1);
WRITE_ONCE(vif->bytes_out, vif->bytes_out + skb->len);

/* We are about to write */
/* XXX: extension headers? */
Expand Down Expand Up @@ -2168,8 +2168,10 @@ static void ip6_mr_forward(struct net *net, struct mr_table *mrt,
}

forward:
mrt->vif_table[vif].pkt_in++;
mrt->vif_table[vif].bytes_in += skb->len;
WRITE_ONCE(mrt->vif_table[vif].pkt_in,
mrt->vif_table[vif].pkt_in + 1);
WRITE_ONCE(mrt->vif_table[vif].bytes_in,
mrt->vif_table[vif].bytes_in + skb->len);

/*
* Forward the frame
Expand Down

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