ipmr: do not acquire mrt_lock in ioctl(SIOCGETVIFCNT)

rcu_read_lock() protection is good enough.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 8a94f9a..bc8b750 100644 (file)
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1611,20 +1611,20 @@ int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg)
                if (vr.vifi >= mrt->maxvif)
                        return -EINVAL;
                vr.vifi = array_index_nospec(vr.vifi, mrt->maxvif);
-               read_lock(&mrt_lock);
+               rcu_read_lock();
                vif = &mrt->vif_table[vr.vifi];
                if (VIF_EXISTS(mrt, vr.vifi)) {
-                       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:
                if (copy_from_user(&sr, arg, sizeof(sr)))
@@ -1686,20 +1686,20 @@ int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
                if (vr.vifi >= mrt->maxvif)
                        return -EINVAL;
                vr.vifi = array_index_nospec(vr.vifi, mrt->maxvif);
-               read_lock(&mrt_lock);
+               rcu_read_lock();
                vif = &mrt->vif_table[vr.vifi];
                if (VIF_EXISTS(mrt, vr.vifi)) {
-                       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:
                if (copy_from_user(&sr, arg, sizeof(sr)))
@@ -1835,8 +1835,8 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
                goto out_free;
 
        if (vif->flags & VIFF_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();
@@ -1885,8 +1885,8 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
                goto out_free;
        }
 
-       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);
 
        skb_dst_drop(skb);
        skb_dst_set(skb, &rt->dst);
@@ -2002,8 +2002,10 @@ static void ip_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 */
        if (c->mfc_origin == htonl(INADDR_ANY) &&