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ipmr: do not acquire mrt_lock before calling ipmr_cache_unresolved()

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rcu_read_lock() protection is good enough.

ipmr_cache_unresolved() uses a dedicated spinlock (mfc_unres_lock)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2022-06-23 04:34:37 +00:00 committed by David S. Miller
parent 559260fd9d
commit 9094db4b80
1 changed files with 8 additions and 17 deletions
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25
net/ipv4/ipmr.c
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@ -680,7 +680,7 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify,
if (VIF_EXISTS(mrt, tmp))
break;
}
mrt->maxvif = tmp+1;
WRITE_ONCE(mrt->maxvif, tmp + 1);
}
write_unlock_bh(&mrt_lock);
@ -905,7 +905,7 @@ static int vif_add(struct net *net, struct mr_table *mrt,
WRITE_ONCE(mrt->mroute_reg_vif_num, vifi);
}
if (vifi+1 > mrt->maxvif)
mrt->maxvif = vifi+1;
WRITE_ONCE(mrt->maxvif, vifi + 1);
write_unlock_bh(&mrt_lock);
call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, dev,
vifi, mrt->id);
@ -1923,11 +1923,12 @@ out_free:
kfree_skb(skb);
}
static int ipmr_find_vif(struct mr_table *mrt, struct net_device *dev)
/* Called with mrt_lock or rcu_read_lock() */
static int ipmr_find_vif(const struct mr_table *mrt, struct net_device *dev)
{
int ct;
for (ct = mrt->maxvif-1; ct >= 0; ct--) {
/* Pairs with WRITE_ONCE() in vif_delete()/vif_add() */
for (ct = READ_ONCE(mrt->maxvif) - 1; ct >= 0; ct--) {
if (rcu_access_pointer(mrt->vif_table[ct].dev) == dev)
break;
}
@ -2161,15 +2162,9 @@ int ip_mr_input(struct sk_buff *skb)
skb = skb2;
}
read_lock(&mrt_lock);
vif = ipmr_find_vif(mrt, dev);
if (vif >= 0) {
int err2 = ipmr_cache_unresolved(mrt, vif, skb, dev);
read_unlock(&mrt_lock);
return err2;
}
read_unlock(&mrt_lock);
if (vif >= 0)
return ipmr_cache_unresolved(mrt, vif, skb, dev);
kfree_skb(skb);
return -ENODEV;
}
@ -2273,18 +2268,15 @@ int ipmr_get_route(struct net *net, struct sk_buff *skb,
int vif = -1;
dev = skb->dev;
read_lock(&mrt_lock);
if (dev)
vif = ipmr_find_vif(mrt, dev);
if (vif < 0) {
read_unlock(&mrt_lock);
rcu_read_unlock();
return -ENODEV;
}
skb2 = skb_realloc_headroom(skb, sizeof(struct iphdr));
if (!skb2) {
read_unlock(&mrt_lock);
rcu_read_unlock();
return -ENOMEM;
}
@ -2298,7 +2290,6 @@ int ipmr_get_route(struct net *net, struct sk_buff *skb,
iph->daddr = daddr;
iph->version = 0;
err = ipmr_cache_unresolved(mrt, vif, skb2, dev);
read_unlock(&mrt_lock);
rcu_read_unlock();
return err;
}