[NET]: split dev_ifsioc() according to locking

This always bugged me: dev_ioctl() called dev_ifsioc() either inside
read_lock(dev_base_lock) or rtnl_lock(), depending on the ioctl being
executed.

This change moves the ioctls executed inside dev_base_lock to a new
function, dev_ifsioc_locked().  Now the locking context is completely
clear to the reader.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 58 insertions, 30 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 13a1bc5d3bfd..1aa07047826e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3083,9 +3083,9 @@ int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa)
 }
 
 /*
- *      Perform the SIOCxIFxxx calls.
+ *      Perform the SIOCxIFxxx calls, inside read_lock(dev_base_lock)
  */
-static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
+static int dev_ifsioc_locked(struct net *net, struct ifreq *ifr, unsigned int cmd)
 {
         int err;
         struct net_device *dev = __dev_get_by_name(net, ifr->ifr_name);
@@ -3098,25 +3098,15 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
                         ifr->ifr_flags = dev_get_flags(dev);
                         return 0;
 
-                case SIOCSIFFLAGS:      /* Set interface flags */
-                        return dev_change_flags(dev, ifr->ifr_flags);
-
                 case SIOCGIFMETRIC:     /* Get the metric on the interface
                                            (currently unused) */
                         ifr->ifr_metric = 0;
                         return 0;
 
-                case SIOCSIFMETRIC:     /* Set the metric on the interface
-                                           (currently unused) */
-                        return -EOPNOTSUPP;
-
                 case SIOCGIFMTU:        /* Get the MTU of a device */
                         ifr->ifr_mtu = dev->mtu;
                         return 0;
 
-                case SIOCSIFMTU:        /* Set the MTU of a device */
-                        return dev_set_mtu(dev, ifr->ifr_mtu);
-
                 case SIOCGIFHWADDR:
                         if (!dev->addr_len)
                                 memset(ifr->ifr_hwaddr.sa_data, 0, sizeof ifr->ifr_hwaddr.sa_data);
@@ -3126,6 +3116,61 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
                         ifr->ifr_hwaddr.sa_family = dev->type;
                         return 0;
 
+                case SIOCGIFSLAVE:
+                        err = -EINVAL;
+                        break;
+
+                case SIOCGIFMAP:
+                        ifr->ifr_map.mem_start = dev->mem_start;
+                        ifr->ifr_map.mem_end   = dev->mem_end;
+                        ifr->ifr_map.base_addr = dev->base_addr;
+                        ifr->ifr_map.irq       = dev->irq;
+                        ifr->ifr_map.dma       = dev->dma;
+                        ifr->ifr_map.port      = dev->if_port;
+                        return 0;
+
+                case SIOCGIFINDEX:
+                        ifr->ifr_ifindex = dev->ifindex;
+                        return 0;
+
+                case SIOCGIFTXQLEN:
+                        ifr->ifr_qlen = dev->tx_queue_len;
+                        return 0;
+
+                default:
+                        /* dev_ioctl() should ensure this case
+                         * is never reached
+                         */
+                        WARN_ON(1);
+                        err = -EINVAL;
+                        break;
+
+        }
+        return err;
+}
+
+/*
+ *      Perform the SIOCxIFxxx calls, inside rtnl_lock()
+ */
+static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
+{
+        int err;
+        struct net_device *dev = __dev_get_by_name(net, ifr->ifr_name);
+
+        if (!dev)
+                return -ENODEV;
+
+        switch (cmd) {
+                case SIOCSIFFLAGS:      /* Set interface flags */
+                        return dev_change_flags(dev, ifr->ifr_flags);
+
+                case SIOCSIFMETRIC:     /* Set the metric on the interface
+                                           (currently unused) */
+                        return -EOPNOTSUPP;
+
+                case SIOCSIFMTU:        /* Set the MTU of a device */
+                        return dev_set_mtu(dev, ifr->ifr_mtu);
+
                 case SIOCSIFHWADDR:
                         return dev_set_mac_address(dev, &ifr->ifr_hwaddr);
 
@@ -3137,15 +3182,6 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
                         call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
                         return 0;
 
-                case SIOCGIFMAP:
-                        ifr->ifr_map.mem_start = dev->mem_start;
-                        ifr->ifr_map.mem_end   = dev->mem_end;
-                        ifr->ifr_map.base_addr = dev->base_addr;
-                        ifr->ifr_map.irq       = dev->irq;
-                        ifr->ifr_map.dma       = dev->dma;
-                        ifr->ifr_map.port      = dev->if_port;
-                        return 0;
-
                 case SIOCSIFMAP:
                         if (dev->set_config) {
                                 if (!netif_device_present(dev))
@@ -3172,14 +3208,6 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
                         return dev_mc_delete(dev, ifr->ifr_hwaddr.sa_data,
                                              dev->addr_len, 1);
 
-                case SIOCGIFINDEX:
-                        ifr->ifr_ifindex = dev->ifindex;
-                        return 0;
-
-                case SIOCGIFTXQLEN:
-                        ifr->ifr_qlen = dev->tx_queue_len;
-                        return 0;
-
                 case SIOCSIFTXQLEN:
                         if (ifr->ifr_qlen < 0)
                                 return -EINVAL;
@@ -3290,7 +3318,7 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg)
                 case SIOCGIFTXQLEN:
                         dev_load(net, ifr.ifr_name);
                         read_lock(&dev_base_lock);
-                        ret = dev_ifsioc(net, &ifr, cmd);
+                        ret = dev_ifsioc_locked(net, &ifr, cmd);
                         read_unlock(&dev_base_lock);
                         if (!ret) {
                                 if (colon)