![Paolo Abeni](/assets/img/avatar_default.png)
Such helper does not cope correctly with NOLOCK qdiscs. In the following patches we will move back qlen to per CPU values for such qdiscs, so qdisc_qlen_sum() is not an option, too. Instead, use qlen only for lock qdiscs, and always set flow off for NOLOCK qdiscs with a not empty tx queue. Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
580 lines
13 KiB
C
580 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
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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 Remi Denis-Courmont
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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/caif_dev.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 unsigned 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 *caifd;
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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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static 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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WARN_ON(caifd == NULL);
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if (!caifd) {
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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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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_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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/* Check if we need to handle xoff */
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if (likely(caifd->netdev->priv_flags & IFF_NO_QUEUE))
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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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struct Qdisc *sch;
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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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sch = rcu_dereference_bh(txq->qdisc);
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if (likely(qdisc_is_empty(sch)))
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goto noxoff;
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/* can check for explicit qdisc len value only !NOLOCK,
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* always set flow off otherwise
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*/
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high = (caifd->netdev->tx_queue_len * q_high) / 100;
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if (!(sch->flags & TCQ_F_NOLOCK) && likely(sch->q.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,
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int (**rcv_func)(struct sk_buff *, struct net_device *,
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struct packet_type *,
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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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strlcpy(caifd->layer.name, dev->name,
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sizeof(caifd->layer.name));
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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 *ptr)
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{
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struct net_device *dev = netdev_notifier_info_to_dev(ptr);
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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);
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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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return -ENOMEM;
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|
|
|
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_netdevice_notifier(&caif_device_notifier);
|
|
dev_remove_pack(&caif_packet_type);
|
|
unregister_pernet_subsys(&caif_net_ops);
|
|
}
|
|
|
|
module_init(caif_device_init);
|
|
module_exit(caif_device_exit);
|