08613e4626
The caif code will register its own pernet_operations, and then register a netdevice_notifier. Each time the netdevice_notifier is triggered, it'll do some stuff... including a lookup of its own pernet stuff with net_generic(). If the net_generic() call ever returns NULL, the caif code will BUG(). That doesn't seem *so* unreasonable, I suppose — it does seem like it should never happen. However, it *does* happen. When we clone a network namespace, setup_net() runs through all the pernet_operations one at a time. It gets to loopback before it gets to caif. And loopback_net_init() registers a netdevice... while caif hasn't been initialised. So the caif netdevice notifier triggers, and immediately goes BUG(). We could imagine a complex and overengineered solution to this generic class of problems, but this patch takes the simple approach. It just makes caif_device_notify() *not* go looking for its pernet data structures if the device it's being notified about isn't a caif device in the first place. Cc: stable@kernel.org Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Acked-by: Sjur Brændeland <sjur.brandeland@stericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
439 lines
9.4 KiB
C
439 lines
9.4 KiB
C
/*
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* CAIF Interface registration.
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* Copyright (C) ST-Ericsson AB 2010
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* Author: Sjur Brendeland/sjur.brandeland@stericsson.com
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* License terms: GNU General Public License (GPL) version 2
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*
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* Borrowed heavily from file: pn_dev.c. Thanks to
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* Remi Denis-Courmont <remi.denis-courmont@nokia.com>
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* and Sakari Ailus <sakari.ailus@nokia.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
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#include <linux/kernel.h>
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#include <linux/if_arp.h>
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#include <linux/net.h>
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#include <linux/netdevice.h>
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#include <linux/mutex.h>
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#include <net/netns/generic.h>
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#include <net/net_namespace.h>
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#include <net/pkt_sched.h>
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#include <net/caif/caif_device.h>
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#include <net/caif/caif_layer.h>
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#include <net/caif/cfpkt.h>
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#include <net/caif/cfcnfg.h>
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MODULE_LICENSE("GPL");
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/* Used for local tracking of the CAIF net devices */
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struct caif_device_entry {
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struct cflayer layer;
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struct list_head list;
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struct net_device *netdev;
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int __percpu *pcpu_refcnt;
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};
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struct caif_device_entry_list {
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struct list_head list;
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/* Protects simulanous deletes in list */
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struct mutex lock;
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};
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struct caif_net {
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struct cfcnfg *cfg;
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struct caif_device_entry_list caifdevs;
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};
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static int caif_net_id;
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struct cfcnfg *get_cfcnfg(struct net *net)
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{
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struct caif_net *caifn;
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BUG_ON(!net);
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caifn = net_generic(net, caif_net_id);
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BUG_ON(!caifn);
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return caifn->cfg;
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}
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EXPORT_SYMBOL(get_cfcnfg);
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static struct caif_device_entry_list *caif_device_list(struct net *net)
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{
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struct caif_net *caifn;
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BUG_ON(!net);
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caifn = net_generic(net, caif_net_id);
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BUG_ON(!caifn);
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return &caifn->caifdevs;
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}
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static void caifd_put(struct caif_device_entry *e)
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{
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irqsafe_cpu_dec(*e->pcpu_refcnt);
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}
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static void caifd_hold(struct caif_device_entry *e)
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{
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irqsafe_cpu_inc(*e->pcpu_refcnt);
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}
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static int caifd_refcnt_read(struct caif_device_entry *e)
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{
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int i, refcnt = 0;
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for_each_possible_cpu(i)
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refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
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return refcnt;
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}
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/* Allocate new CAIF device. */
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static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
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{
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struct caif_device_entry_list *caifdevs;
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struct caif_device_entry *caifd;
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caifdevs = caif_device_list(dev_net(dev));
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BUG_ON(!caifdevs);
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caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
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if (!caifd)
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return NULL;
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caifd->pcpu_refcnt = alloc_percpu(int);
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if (!caifd->pcpu_refcnt) {
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kfree(caifd);
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return NULL;
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}
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caifd->netdev = dev;
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dev_hold(dev);
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return caifd;
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}
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static struct caif_device_entry *caif_get(struct net_device *dev)
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{
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struct caif_device_entry_list *caifdevs =
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caif_device_list(dev_net(dev));
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struct caif_device_entry *caifd;
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BUG_ON(!caifdevs);
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list_for_each_entry_rcu(caifd, &caifdevs->list, list) {
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if (caifd->netdev == dev)
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return caifd;
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}
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return NULL;
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}
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static int transmit(struct cflayer *layer, struct cfpkt *pkt)
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{
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int err;
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struct caif_device_entry *caifd =
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container_of(layer, struct caif_device_entry, layer);
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struct sk_buff *skb;
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skb = cfpkt_tonative(pkt);
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skb->dev = caifd->netdev;
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err = dev_queue_xmit(skb);
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if (err > 0)
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err = -EIO;
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return err;
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}
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/*
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* Stuff received packets into the CAIF stack.
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* On error, returns non-zero and releases the skb.
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*/
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static int receive(struct sk_buff *skb, struct net_device *dev,
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struct packet_type *pkttype, struct net_device *orig_dev)
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{
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struct cfpkt *pkt;
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struct caif_device_entry *caifd;
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int err;
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pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
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rcu_read_lock();
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caifd = caif_get(dev);
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if (!caifd || !caifd->layer.up || !caifd->layer.up->receive ||
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!netif_oper_up(caifd->netdev)) {
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rcu_read_unlock();
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kfree_skb(skb);
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return NET_RX_DROP;
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}
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/* Hold reference to netdevice while using CAIF stack */
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caifd_hold(caifd);
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rcu_read_unlock();
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err = caifd->layer.up->receive(caifd->layer.up, pkt);
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/* For -EILSEQ the packet is not freed so so it now */
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if (err == -EILSEQ)
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cfpkt_destroy(pkt);
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/* Release reference to stack upwards */
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caifd_put(caifd);
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return 0;
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}
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static struct packet_type caif_packet_type __read_mostly = {
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.type = cpu_to_be16(ETH_P_CAIF),
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.func = receive,
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};
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static void dev_flowctrl(struct net_device *dev, int on)
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{
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struct caif_device_entry *caifd;
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rcu_read_lock();
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caifd = caif_get(dev);
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if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
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rcu_read_unlock();
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return;
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}
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caifd_hold(caifd);
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rcu_read_unlock();
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caifd->layer.up->ctrlcmd(caifd->layer.up,
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on ?
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_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
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_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
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caifd->layer.id);
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caifd_put(caifd);
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}
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/* notify Caif of device events */
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static int caif_device_notify(struct notifier_block *me, unsigned long what,
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void *arg)
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{
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struct net_device *dev = arg;
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struct caif_device_entry *caifd = NULL;
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struct caif_dev_common *caifdev;
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enum cfcnfg_phy_preference pref;
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enum cfcnfg_phy_type phy_type;
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struct cfcnfg *cfg;
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struct caif_device_entry_list *caifdevs;
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if (dev->type != ARPHRD_CAIF)
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return 0;
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cfg = get_cfcnfg(dev_net(dev));
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if (cfg == NULL)
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return 0;
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caifdevs = caif_device_list(dev_net(dev));
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switch (what) {
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case NETDEV_REGISTER:
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caifd = caif_device_alloc(dev);
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if (!caifd)
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return 0;
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caifdev = netdev_priv(dev);
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caifdev->flowctrl = dev_flowctrl;
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caifd->layer.transmit = transmit;
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if (caifdev->use_frag)
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phy_type = CFPHYTYPE_FRAG;
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else
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phy_type = CFPHYTYPE_CAIF;
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switch (caifdev->link_select) {
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case CAIF_LINK_HIGH_BANDW:
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pref = CFPHYPREF_HIGH_BW;
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break;
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case CAIF_LINK_LOW_LATENCY:
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pref = CFPHYPREF_LOW_LAT;
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break;
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default:
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pref = CFPHYPREF_HIGH_BW;
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break;
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}
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strncpy(caifd->layer.name, dev->name,
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sizeof(caifd->layer.name) - 1);
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caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
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mutex_lock(&caifdevs->lock);
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list_add_rcu(&caifd->list, &caifdevs->list);
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cfcnfg_add_phy_layer(cfg,
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phy_type,
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dev,
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&caifd->layer,
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pref,
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caifdev->use_fcs,
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caifdev->use_stx);
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mutex_unlock(&caifdevs->lock);
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break;
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case NETDEV_UP:
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rcu_read_lock();
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caifd = caif_get(dev);
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if (caifd == NULL) {
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rcu_read_unlock();
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break;
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}
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cfcnfg_set_phy_state(cfg, &caifd->layer, true);
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rcu_read_unlock();
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break;
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case NETDEV_DOWN:
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rcu_read_lock();
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caifd = caif_get(dev);
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if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
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rcu_read_unlock();
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return -EINVAL;
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}
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cfcnfg_set_phy_state(cfg, &caifd->layer, false);
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caifd_hold(caifd);
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rcu_read_unlock();
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caifd->layer.up->ctrlcmd(caifd->layer.up,
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_CAIF_CTRLCMD_PHYIF_DOWN_IND,
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caifd->layer.id);
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caifd_put(caifd);
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break;
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case NETDEV_UNREGISTER:
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mutex_lock(&caifdevs->lock);
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caifd = caif_get(dev);
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if (caifd == NULL) {
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mutex_unlock(&caifdevs->lock);
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break;
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}
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list_del_rcu(&caifd->list);
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/*
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* NETDEV_UNREGISTER is called repeatedly until all reference
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* counts for the net-device are released. If references to
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* caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
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* the next call to NETDEV_UNREGISTER.
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*
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* If any packets are in flight down the CAIF Stack,
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* cfcnfg_del_phy_layer will return nonzero.
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* If no packets are in flight, the CAIF Stack associated
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* with the net-device un-registering is freed.
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*/
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if (caifd_refcnt_read(caifd) != 0 ||
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cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
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pr_info("Wait for device inuse\n");
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/* Enrole device if CAIF Stack is still in use */
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list_add_rcu(&caifd->list, &caifdevs->list);
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mutex_unlock(&caifdevs->lock);
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break;
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}
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synchronize_rcu();
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dev_put(caifd->netdev);
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free_percpu(caifd->pcpu_refcnt);
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kfree(caifd);
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mutex_unlock(&caifdevs->lock);
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break;
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}
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return 0;
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}
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static struct notifier_block caif_device_notifier = {
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.notifier_call = caif_device_notify,
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.priority = 0,
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};
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/* Per-namespace Caif devices handling */
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static int caif_init_net(struct net *net)
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{
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struct caif_net *caifn = net_generic(net, caif_net_id);
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BUG_ON(!caifn);
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INIT_LIST_HEAD(&caifn->caifdevs.list);
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mutex_init(&caifn->caifdevs.lock);
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caifn->cfg = cfcnfg_create();
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if (!caifn->cfg) {
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pr_warn("can't create cfcnfg\n");
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return -ENOMEM;
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}
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return 0;
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}
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static void caif_exit_net(struct net *net)
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{
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struct caif_device_entry *caifd, *tmp;
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struct caif_device_entry_list *caifdevs =
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caif_device_list(net);
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struct cfcnfg *cfg;
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rtnl_lock();
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mutex_lock(&caifdevs->lock);
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cfg = get_cfcnfg(net);
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if (cfg == NULL) {
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mutex_unlock(&caifdevs->lock);
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return;
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}
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list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
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int i = 0;
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list_del_rcu(&caifd->list);
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cfcnfg_set_phy_state(cfg, &caifd->layer, false);
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while (i < 10 &&
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(caifd_refcnt_read(caifd) != 0 ||
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cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
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pr_info("Wait for device inuse\n");
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msleep(250);
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i++;
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}
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synchronize_rcu();
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dev_put(caifd->netdev);
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free_percpu(caifd->pcpu_refcnt);
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kfree(caifd);
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}
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cfcnfg_remove(cfg);
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mutex_unlock(&caifdevs->lock);
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rtnl_unlock();
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}
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static struct pernet_operations caif_net_ops = {
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.init = caif_init_net,
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.exit = caif_exit_net,
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.id = &caif_net_id,
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.size = sizeof(struct caif_net),
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};
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/* Initialize Caif devices list */
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static int __init caif_device_init(void)
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{
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int result;
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result = register_pernet_device(&caif_net_ops);
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if (result)
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return result;
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register_netdevice_notifier(&caif_device_notifier);
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dev_add_pack(&caif_packet_type);
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return result;
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}
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static void __exit caif_device_exit(void)
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{
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unregister_pernet_device(&caif_net_ops);
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unregister_netdevice_notifier(&caif_device_notifier);
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dev_remove_pack(&caif_packet_type);
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}
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module_init(caif_device_init);
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module_exit(caif_device_exit);
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