uml: network interface hotplug error handling

This fixes a number of problems associated with network interface hotplug.

The userspace initialization function can fail in some cases, but the
failure was never passed back to eth_configure, which proceeded with the
configuration.  This results in a zombie device that is present, but can't
work.  This is fixed by allowing the initialization routines to return an
error, which is checked, and the configuration aborted on failure.

eth_configure failed to check for many failures.  Even when it did check,
it didn't undo whatever initializations has already happened, so a present,
but partially initialized and non-working device could result.  It now
checks everything that can fail, and bails out, undoing whatever had been
done.

The return value of eth_configure was always ignored, so it is now just
void.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/um/drivers/daemon_user.c b/arch/um/drivers/daemon_user.c
index 09d1de9..d0b656a 100644 (file)
--- a/arch/um/drivers/daemon_user.c
+++ b/arch/um/drivers/daemon_user.c
@@ -123,7 +123,7 @@ static int connect_to_switch(struct daemon_data *pri)
        return err;
 }
 
-static void daemon_user_init(void *data, void *dev)
+static int daemon_user_init(void *data, void *dev)
 {
        struct daemon_data *pri = data;
        struct timeval tv;
@@ -146,7 +146,10 @@ static void daemon_user_init(void *data, void *dev)
        if(pri->fd < 0){
                kfree(pri->local_addr);
                pri->local_addr = NULL;
+               return pri->fd;
        }
+
+       return 0;
 }
 
 static int daemon_open(void *data)

diff --git a/arch/um/drivers/mcast_user.c b/arch/um/drivers/mcast_user.c
index cfaa2cc..0f64d94 100644 (file)
--- a/arch/um/drivers/mcast_user.c
+++ b/arch/um/drivers/mcast_user.c
@@ -42,12 +42,13 @@ static struct sockaddr_in *new_addr(char *addr, unsigned short port)
        return sin;
 }
 
-static void mcast_user_init(void *data, void *dev)
+static int mcast_user_init(void *data, void *dev)
 {
        struct mcast_data *pri = data;
 
        pri->mcast_addr = new_addr(pri->addr, pri->port);
        pri->dev = dev;
+       return 0;
 }
 
 static void mcast_remove(void *data)

diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c
index 8593037..ac746fb 100644 (file)
--- a/arch/um/drivers/net_kern.c
+++ b/arch/um/drivers/net_kern.c
@@ -325,8 +325,8 @@ static struct platform_driver uml_net_driver = {
 };
 static int driver_registered;
 
-static int eth_configure(int n, void *init, char *mac,
-                        struct transport *transport)
+static void eth_configure(int n, void *init, char *mac,
+                         struct transport *transport)
 {
        struct uml_net *device;
        struct net_device *dev;
@@ -339,16 +339,12 @@ static int eth_configure(int n, void *init, char *mac,
        device = kzalloc(sizeof(*device), GFP_KERNEL);
        if (device == NULL) {
                printk(KERN_ERR "eth_configure failed to allocate uml_net\n");
-               return(1);
+               return;
        }
 
        INIT_LIST_HEAD(&device->list);
        device->index = n;
 
-       spin_lock(&devices_lock);
-       list_add(&device->list, &devices);
-       spin_unlock(&devices_lock);
-
        setup_etheraddr(mac, device->mac);
 
        printk(KERN_INFO "Netdevice %d ", n);
@@ -360,7 +356,7 @@ static int eth_configure(int n, void *init, char *mac,
        dev = alloc_etherdev(size);
        if (dev == NULL) {
                printk(KERN_ERR "eth_configure: failed to allocate device\n");
-               return 1;
+               goto out_free_device;
        }
 
        lp = dev->priv;
@@ -376,7 +372,8 @@ static int eth_configure(int n, void *init, char *mac,
        }
        device->pdev.id = n;
        device->pdev.name = DRIVER_NAME;
-       platform_device_register(&device->pdev);
+       if(platform_device_register(&device->pdev))
+               goto out_free_netdev;
        SET_NETDEV_DEV(dev,&device->pdev.dev);
 
        /* If this name ends up conflicting with an existing registered
@@ -386,31 +383,12 @@ static int eth_configure(int n, void *init, char *mac,
        snprintf(dev->name, sizeof(dev->name), "eth%d", n);
        device->dev = dev;
 
+       /*
+        * These just fill in a data structure, so there's no failure
+        * to be worried about.
+        */
        (*transport->kern->init)(dev, init);
 
-       dev->mtu = transport->user->max_packet;
-       dev->open = uml_net_open;
-       dev->hard_start_xmit = uml_net_start_xmit;
-       dev->stop = uml_net_close;
-       dev->get_stats = uml_net_get_stats;
-       dev->set_multicast_list = uml_net_set_multicast_list;
-       dev->tx_timeout = uml_net_tx_timeout;
-       dev->set_mac_address = uml_net_set_mac;
-       dev->change_mtu = uml_net_change_mtu;
-       dev->ethtool_ops = &uml_net_ethtool_ops;
-       dev->watchdog_timeo = (HZ >> 1);
-       dev->irq = UM_ETH_IRQ;
-
-       rtnl_lock();
-       err = register_netdevice(dev);
-       rtnl_unlock();
-       if (err) {
-               device->dev = NULL;
-               /* XXX: should we call ->remove() here? */
-               free_netdev(dev);
-               return 1;
-       }
-
        /* lp.user is the first four bytes of the transport data, which
         * has already been initialized.  This structure assignment will
         * overwrite that, so we make sure that .user gets overwritten with
@@ -438,12 +416,45 @@ static int eth_configure(int n, void *init, char *mac,
        lp->tl.function = uml_net_user_timer_expire;
        memcpy(lp->mac, device->mac, sizeof(lp->mac));
 
-       if (transport->user->init)
-               (*transport->user->init)(&lp->user, dev);
+       if ((transport->user->init != NULL) &&
+           ((*transport->user->init)(&lp->user, dev) != 0))
+               goto out_unregister;
 
        set_ether_mac(dev, device->mac);
+       dev->mtu = transport->user->max_packet;
+       dev->open = uml_net_open;
+       dev->hard_start_xmit = uml_net_start_xmit;
+       dev->stop = uml_net_close;
+       dev->get_stats = uml_net_get_stats;
+       dev->set_multicast_list = uml_net_set_multicast_list;
+       dev->tx_timeout = uml_net_tx_timeout;
+       dev->set_mac_address = uml_net_set_mac;
+       dev->change_mtu = uml_net_change_mtu;
+       dev->ethtool_ops = &uml_net_ethtool_ops;
+       dev->watchdog_timeo = (HZ >> 1);
+       dev->irq = UM_ETH_IRQ;
 
-       return 0;
+       rtnl_lock();
+       err = register_netdevice(dev);
+       rtnl_unlock();
+       if (err)
+               goto out_undo_user_init;
+
+       spin_lock(&devices_lock);
+       list_add(&device->list, &devices);
+       spin_unlock(&devices_lock);
+
+       return;
+
+out_undo_user_init:
+       if (transport->user->init != NULL)
+               (*transport->user->remove)(&lp->user);
+out_unregister:
+       platform_device_unregister(&device->pdev);
+out_free_netdev:
+       free_netdev(dev);
+out_free_device: ;
+       kfree(device);
 }
 
 static struct uml_net *find_device(int n)

diff --git a/arch/um/drivers/pcap_user.c b/arch/um/drivers/pcap_user.c
index a1747dc..dc0a903 100644 (file)
--- a/arch/um/drivers/pcap_user.c
+++ b/arch/um/drivers/pcap_user.c
@@ -18,7 +18,7 @@
 
 #define PCAP_FD(p) (*(int *)(p))
 
-static void pcap_user_init(void *data, void *dev)
+static int pcap_user_init(void *data, void *dev)
 {
        struct pcap_data *pri = data;
        pcap_t *p;
@@ -28,11 +28,12 @@ static void pcap_user_init(void *data, void *dev)
        if(p == NULL){
                printk("pcap_user_init : pcap_open_live failed - '%s'\n", 
                       errors);
-               return;
+               return -EINVAL;
        }
 
        pri->dev = dev;
        pri->pcap = p;
+       return 0;
 }
 
 static int pcap_open(void *data)

diff --git a/arch/um/drivers/slip_user.c b/arch/um/drivers/slip_user.c
index 7eddacc..329c072 100644 (file)
--- a/arch/um/drivers/slip_user.c
+++ b/arch/um/drivers/slip_user.c
@@ -17,11 +17,12 @@
 #include "os.h"
 #include "um_malloc.h"
 
-void slip_user_init(void *data, void *dev)
+static int slip_user_init(void *data, void *dev)
 {
        struct slip_data *pri = data;
 
        pri->dev = dev;
+       return 0;
 }
 
 static int set_up_tty(int fd)

diff --git a/arch/um/drivers/slirp_user.c b/arch/um/drivers/slirp_user.c
index ce5e85d..f0a40ab 100644 (file)
--- a/arch/um/drivers/slirp_user.c
+++ b/arch/um/drivers/slirp_user.c
@@ -15,11 +15,12 @@
 #include "slip_common.h"
 #include "os.h"
 
-void slirp_user_init(void *data, void *dev)
+static int slirp_user_init(void *data, void *dev)
 {
        struct slirp_data *pri = data;
 
        pri->dev = dev;
+       return 0;
 }
 
 struct slirp_pre_exec_data {

diff --git a/arch/um/include/net_user.h b/arch/um/include/net_user.h
index 19f207c..cfe7c50 100644 (file)
--- a/arch/um/include/net_user.h
+++ b/arch/um/include/net_user.h
@@ -14,7 +14,7 @@
 #define UML_NET_VERSION (4)
 
 struct net_user_info {
-       void (*init)(void *, void *);
+       int (*init)(void *, void *);
        int (*open)(void *);
        void (*close)(int, void *);
        void (*remove)(void *);

diff --git a/arch/um/os-Linux/drivers/ethertap_user.c b/arch/um/os-Linux/drivers/ethertap_user.c
index f3ad0da..2cc2d3e 100644 (file)
--- a/arch/um/os-Linux/drivers/ethertap_user.c
+++ b/arch/um/os-Linux/drivers/ethertap_user.c
@@ -24,11 +24,12 @@
 
 #define MAX_PACKET ETH_MAX_PACKET
 
-void etap_user_init(void *data, void *dev)
+static int etap_user_init(void *data, void *dev)
 {
        struct ethertap_data *pri = data;
 
        pri->dev = dev;
+       return 0;
 }
 
 struct addr_change {

diff --git a/arch/um/os-Linux/drivers/tuntap_user.c b/arch/um/os-Linux/drivers/tuntap_user.c
index ab63fb6..506ef09 100644 (file)
--- a/arch/um/os-Linux/drivers/tuntap_user.c
+++ b/arch/um/os-Linux/drivers/tuntap_user.c
@@ -24,11 +24,12 @@
 
 #define MAX_PACKET ETH_MAX_PACKET
 
-void tuntap_user_init(void *data, void *dev)
+static int tuntap_user_init(void *data, void *dev)
 {
        struct tuntap_data *pri = data;
 
        pri->dev = dev;
+       return 0;
 }
 
 static void tuntap_add_addr(unsigned char *addr, unsigned char *netmask,