[PATCH 3/4] ipv4: use symbol_get to access ipip symbols

[Christoph Hellwig]

Instead of going through the ioctl handler from kernel space, use
symbol_get to access the ip_tunnel_ioctl directly.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 net/ipv4/ipmr.c | 28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 6bf2a88abe86e..3780ab694c574 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -438,10 +438,9 @@ static bool ipmr_init_vif_indev(const struct net_device 
*dev)
 
 static struct net_device *ipmr_new_tunnel(struct net *net, struct vifctl *v)
 {
-       mm_segment_t oldfs = get_fs();
+       int (*tunnel_ctl)(struct net_device *, struct ip_tunnel_parm *, int);
        struct net_device *tunnel_dev, *new_dev;
        struct ip_tunnel_parm p = { };
-       struct ifreq ifr;
        int err;
 
        tunnel_dev = __dev_get_by_name(net, "tunl0");
@@ -454,21 +453,17 @@ static struct net_device *ipmr_new_tunnel(struct net 
*net, struct vifctl *v)
        p.iph.ihl = 5;
        p.iph.protocol = IPPROTO_IPIP;
        sprintf(p.name, "dvmrp%d", v->vifc_vifi);
-       ifr.ifr_ifru.ifru_data = (__force void __user *)&p;
 
-       if (!tunnel_dev->netdev_ops->ndo_do_ioctl)
-               goto out;
+       tunnel_ctl = symbol_get(ip_tunnel_ioctl);
+       if (!tunnel_ctl)
+               return ERR_PTR(-ENOBUFS);
 
-       set_fs(KERNEL_DS);
-       err = tunnel_dev->netdev_ops->ndo_do_ioctl(tunnel_dev, &ifr,
-                       SIOCADDTUNNEL);
-       set_fs(oldfs);
-       if (err)
-               goto out;
+       if (tunnel_ctl(tunnel_dev, &p, SIOCADDTUNNEL))
+               goto out_symbol_put;
 
        new_dev = __dev_get_by_name(net, p.name);
        if (!new_dev)
-               goto out;
+               goto out_symbol_put;
 
        new_dev->flags |= IFF_MULTICAST;
        if (!ipmr_init_vif_indev(new_dev))
@@ -479,17 +474,18 @@ static struct net_device *ipmr_new_tunnel(struct net 
*net, struct vifctl *v)
        err = dev_set_allmulti(new_dev, 1);
        if (err) {
                dev_close(new_dev);
-               set_fs(KERNEL_DS);
-               tunnel_dev->netdev_ops->ndo_do_ioctl(tunnel_dev, &ifr,
-                               SIOCDELTUNNEL);
-               set_fs(oldfs);
+               tunnel_ctl(tunnel_dev, &p, SIOCDELTUNNEL);
                dev_put(new_dev);
                new_dev = ERR_PTR(err);
        }
+
+       symbol_put(ip_tunnel_ioctl);
        return new_dev;
 
 out_unregister:
        unregister_netdevice(new_dev);
+out_symbol_put:
+       symbol_put(ipmr_new_tunnel);
 out:
        return ERR_PTR(-ENOBUFS);
 }
-- 
2.26.2