![Eric W. Biederman](/assets/img/avatar_default.png)
caif is a subsystem and as such it needs to register with register_pernet_subsys instead of register_pernet_device. Among other problems using register_pernet_device was resulting in net_generic being called before the caif_net structure was allocated. Which has been causing net_generic to fail with either BUG_ON's or by return NULL pointers. A more ugly problem that could be caused is packets in flight why the subsystem is shutting down. To remove confusion also remove the cruft cause by inappropriately trying to fix this bug. With the aid of the previous patch I have tested this patch and confirmed that using register_pernet_subsys makes the failure go away as it should. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Sjur Brændeland <sjur.brandeland@stericsson.com> Tested-by: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
574 lines
13 KiB
C
574 lines
13 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 <linux/module.h>
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#include <linux/spinlock.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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#include <net/caif/cfserl.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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spinlock_t flow_lock;
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struct sk_buff *xoff_skb;
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void (*xoff_skb_dtor)(struct sk_buff *skb);
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bool xoff;
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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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static int q_high = 50; /* Percent */
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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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caifn = net_generic(net, caif_net_id);
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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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caifn = net_generic(net, caif_net_id);
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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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this_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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this_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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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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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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void caif_flow_cb(struct sk_buff *skb)
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{
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struct caif_device_entry *caifd;
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void (*dtor)(struct sk_buff *skb) = NULL;
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bool send_xoff;
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WARN_ON(skb->dev == NULL);
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rcu_read_lock();
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caifd = caif_get(skb->dev);
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caifd_hold(caifd);
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rcu_read_unlock();
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spin_lock_bh(&caifd->flow_lock);
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send_xoff = caifd->xoff;
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caifd->xoff = 0;
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dtor = caifd->xoff_skb_dtor;
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if (WARN_ON(caifd->xoff_skb != skb))
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skb = NULL;
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caifd->xoff_skb = NULL;
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caifd->xoff_skb_dtor = NULL;
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spin_unlock_bh(&caifd->flow_lock);
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if (dtor && skb)
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dtor(skb);
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if (send_xoff)
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caifd->layer.up->
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ctrlcmd(caifd->layer.up,
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_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
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caifd->layer.id);
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caifd_put(caifd);
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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, high = 0, qlen = 0;
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struct caif_dev_common *caifdev;
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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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struct netdev_queue *txq;
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rcu_read_lock_bh();
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skb = cfpkt_tonative(pkt);
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skb->dev = caifd->netdev;
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skb_reset_network_header(skb);
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skb->protocol = htons(ETH_P_CAIF);
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caifdev = netdev_priv(caifd->netdev);
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/* Check if we need to handle xoff */
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if (likely(caifd->netdev->tx_queue_len == 0))
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goto noxoff;
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if (unlikely(caifd->xoff))
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goto noxoff;
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if (likely(!netif_queue_stopped(caifd->netdev))) {
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/* If we run with a TX queue, check if the queue is too long*/
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txq = netdev_get_tx_queue(skb->dev, 0);
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qlen = qdisc_qlen(rcu_dereference_bh(txq->qdisc));
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if (likely(qlen == 0))
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goto noxoff;
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high = (caifd->netdev->tx_queue_len * q_high) / 100;
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if (likely(qlen < high))
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goto noxoff;
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}
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/* Hold lock while accessing xoff */
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spin_lock_bh(&caifd->flow_lock);
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if (caifd->xoff) {
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spin_unlock_bh(&caifd->flow_lock);
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goto noxoff;
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}
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/*
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* Handle flow off, we do this by temporary hi-jacking this
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* skb's destructor function, and replace it with our own
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* flow-on callback. The callback will set flow-on and call
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* the original destructor.
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*/
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pr_debug("queue has stopped(%d) or is full (%d > %d)\n",
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netif_queue_stopped(caifd->netdev),
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qlen, high);
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caifd->xoff = 1;
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caifd->xoff_skb = skb;
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caifd->xoff_skb_dtor = skb->destructor;
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skb->destructor = caif_flow_cb;
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spin_unlock_bh(&caifd->flow_lock);
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caifd->layer.up->ctrlcmd(caifd->layer.up,
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_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
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caifd->layer.id);
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noxoff:
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rcu_read_unlock_bh();
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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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if (err != 0)
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err = NET_RX_DROP;
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return err;
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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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void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
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struct cflayer *link_support, int head_room,
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struct cflayer **layer, int (**rcv_func)(
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struct sk_buff *, struct net_device *,
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struct packet_type *, struct net_device *))
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{
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struct caif_device_entry *caifd;
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enum cfcnfg_phy_preference pref;
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struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
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struct caif_device_entry_list *caifdevs;
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caifdevs = caif_device_list(dev_net(dev));
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caifd = caif_device_alloc(dev);
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if (!caifd)
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return;
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*layer = &caifd->layer;
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spin_lock_init(&caifd->flow_lock);
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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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mutex_lock(&caifdevs->lock);
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list_add_rcu(&caifd->list, &caifdevs->list);
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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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caifd->layer.transmit = transmit;
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cfcnfg_add_phy_layer(cfg,
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dev,
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&caifd->layer,
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pref,
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link_support,
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caifdev->use_fcs,
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head_room);
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mutex_unlock(&caifdevs->lock);
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if (rcv_func)
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*rcv_func = receive;
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}
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EXPORT_SYMBOL(caif_enroll_dev);
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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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struct cfcnfg *cfg;
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struct cflayer *layer, *link_support;
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int head_room = 0;
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struct caif_device_entry_list *caifdevs;
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cfg = get_cfcnfg(dev_net(dev));
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caifdevs = caif_device_list(dev_net(dev));
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caifd = caif_get(dev);
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if (caifd == NULL && dev->type != ARPHRD_CAIF)
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return 0;
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switch (what) {
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case NETDEV_REGISTER:
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if (caifd != NULL)
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break;
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caifdev = netdev_priv(dev);
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link_support = NULL;
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if (caifdev->use_frag) {
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head_room = 1;
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link_support = cfserl_create(dev->ifindex,
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caifdev->use_stx);
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if (!link_support) {
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pr_warn("Out of memory\n");
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break;
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}
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}
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caif_enroll_dev(dev, caifdev, link_support, head_room,
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&layer, NULL);
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caifdev->flowctrl = dev_flowctrl;
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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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caifd->xoff = 0;
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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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spin_lock_bh(&caifd->flow_lock);
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/*
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* Replace our xoff-destructor with original destructor.
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* We trust that skb->destructor *always* is called before
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* the skb reference is invalid. The hijacked SKB destructor
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* takes the flow_lock so manipulating the skb->destructor here
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* should be safe.
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*/
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if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL)
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caifd->xoff_skb->destructor = caifd->xoff_skb_dtor;
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caifd->xoff = 0;
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caifd->xoff_skb_dtor = NULL;
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caifd->xoff_skb = NULL;
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spin_unlock_bh(&caifd->flow_lock);
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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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INIT_LIST_HEAD(&caifn->caifdevs.list);
|
|
mutex_init(&caifn->caifdevs.lock);
|
|
|
|
caifn->cfg = cfcnfg_create();
|
|
if (!caifn->cfg)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void caif_exit_net(struct net *net)
|
|
{
|
|
struct caif_device_entry *caifd, *tmp;
|
|
struct caif_device_entry_list *caifdevs =
|
|
caif_device_list(net);
|
|
struct cfcnfg *cfg = get_cfcnfg(net);
|
|
|
|
rtnl_lock();
|
|
mutex_lock(&caifdevs->lock);
|
|
|
|
list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
|
|
int i = 0;
|
|
list_del_rcu(&caifd->list);
|
|
cfcnfg_set_phy_state(cfg, &caifd->layer, false);
|
|
|
|
while (i < 10 &&
|
|
(caifd_refcnt_read(caifd) != 0 ||
|
|
cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
|
|
|
|
pr_info("Wait for device inuse\n");
|
|
msleep(250);
|
|
i++;
|
|
}
|
|
synchronize_rcu();
|
|
dev_put(caifd->netdev);
|
|
free_percpu(caifd->pcpu_refcnt);
|
|
kfree(caifd);
|
|
}
|
|
cfcnfg_remove(cfg);
|
|
|
|
mutex_unlock(&caifdevs->lock);
|
|
rtnl_unlock();
|
|
}
|
|
|
|
static struct pernet_operations caif_net_ops = {
|
|
.init = caif_init_net,
|
|
.exit = caif_exit_net,
|
|
.id = &caif_net_id,
|
|
.size = sizeof(struct caif_net),
|
|
};
|
|
|
|
/* Initialize Caif devices list */
|
|
static int __init caif_device_init(void)
|
|
{
|
|
int result;
|
|
|
|
result = register_pernet_subsys(&caif_net_ops);
|
|
|
|
if (result)
|
|
return result;
|
|
|
|
register_netdevice_notifier(&caif_device_notifier);
|
|
dev_add_pack(&caif_packet_type);
|
|
|
|
return result;
|
|
}
|
|
|
|
static void __exit caif_device_exit(void)
|
|
{
|
|
unregister_pernet_subsys(&caif_net_ops);
|
|
unregister_netdevice_notifier(&caif_device_notifier);
|
|
dev_remove_pack(&caif_packet_type);
|
|
}
|
|
|
|
module_init(caif_device_init);
|
|
module_exit(caif_device_exit);
|