linux/net/caif/caif_dev.c

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/*
* CAIF Interface registration.
* Copyright (C) ST-Ericsson AB 2010
* Author: Sjur Brendeland
* License terms: GNU General Public License (GPL) version 2
*
* Borrowed heavily from file: pn_dev.c. Thanks to Remi Denis-Courmont
* and Sakari Ailus <sakari.ailus@nokia.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
#include <linux/kernel.h>
#include <linux/if_arp.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <net/netns/generic.h>
#include <net/net_namespace.h>
#include <net/pkt_sched.h>
#include <net/caif/caif_device.h>
#include <net/caif/caif_layer.h>
#include <net/caif/caif_dev.h>
#include <net/caif/cfpkt.h>
#include <net/caif/cfcnfg.h>
#include <net/caif/cfserl.h>
MODULE_LICENSE("GPL");
/* Used for local tracking of the CAIF net devices */
struct caif_device_entry {
struct cflayer layer;
struct list_head list;
struct net_device *netdev;
int __percpu *pcpu_refcnt;
spinlock_t flow_lock;
struct sk_buff *xoff_skb;
void (*xoff_skb_dtor)(struct sk_buff *skb);
bool xoff;
};
struct caif_device_entry_list {
struct list_head list;
/* Protects simulanous deletes in list */
struct mutex lock;
};
struct caif_net {
struct cfcnfg *cfg;
struct caif_device_entry_list caifdevs;
};
static int caif_net_id;
static int q_high = 50; /* Percent */
struct cfcnfg *get_cfcnfg(struct net *net)
{
struct caif_net *caifn;
caifn = net_generic(net, caif_net_id);
return caifn->cfg;
}
EXPORT_SYMBOL(get_cfcnfg);
static struct caif_device_entry_list *caif_device_list(struct net *net)
{
struct caif_net *caifn;
caifn = net_generic(net, caif_net_id);
return &caifn->caifdevs;
}
static void caifd_put(struct caif_device_entry *e)
{
this_cpu_dec(*e->pcpu_refcnt);
}
static void caifd_hold(struct caif_device_entry *e)
{
this_cpu_inc(*e->pcpu_refcnt);
}
static int caifd_refcnt_read(struct caif_device_entry *e)
{
int i, refcnt = 0;
for_each_possible_cpu(i)
refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
return refcnt;
}
/* Allocate new CAIF device. */
static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
{
struct caif_device_entry *caifd;
caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
if (!caifd)
return NULL;
caifd->pcpu_refcnt = alloc_percpu(int);
if (!caifd->pcpu_refcnt) {
kfree(caifd);
return NULL;
}
caifd->netdev = dev;
dev_hold(dev);
return caifd;
}
static struct caif_device_entry *caif_get(struct net_device *dev)
{
struct caif_device_entry_list *caifdevs =
caif_device_list(dev_net(dev));
struct caif_device_entry *caifd;
list_for_each_entry_rcu(caifd, &caifdevs->list, list) {
if (caifd->netdev == dev)
return caifd;
}
return NULL;
}
static void caif_flow_cb(struct sk_buff *skb)
{
struct caif_device_entry *caifd;
void (*dtor)(struct sk_buff *skb) = NULL;
bool send_xoff;
WARN_ON(skb->dev == NULL);
rcu_read_lock();
caifd = caif_get(skb->dev);
WARN_ON(caifd == NULL);
if (caifd == NULL)
return;
caifd_hold(caifd);
rcu_read_unlock();
spin_lock_bh(&caifd->flow_lock);
send_xoff = caifd->xoff;
caifd->xoff = 0;
dtor = caifd->xoff_skb_dtor;
if (WARN_ON(caifd->xoff_skb != skb))
skb = NULL;
caifd->xoff_skb = NULL;
caifd->xoff_skb_dtor = NULL;
spin_unlock_bh(&caifd->flow_lock);
if (dtor && skb)
dtor(skb);
if (send_xoff)
caifd->layer.up->
ctrlcmd(caifd->layer.up,
_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
caifd->layer.id);
caifd_put(caifd);
}
static int transmit(struct cflayer *layer, struct cfpkt *pkt)
{
int err, high = 0, qlen = 0;
struct caif_device_entry *caifd =
container_of(layer, struct caif_device_entry, layer);
struct sk_buff *skb;
struct netdev_queue *txq;
rcu_read_lock_bh();
skb = cfpkt_tonative(pkt);
skb->dev = caifd->netdev;
skb_reset_network_header(skb);
skb->protocol = htons(ETH_P_CAIF);
/* Check if we need to handle xoff */
if (likely(caifd->netdev->priv_flags & IFF_NO_QUEUE))
goto noxoff;
if (unlikely(caifd->xoff))
goto noxoff;
if (likely(!netif_queue_stopped(caifd->netdev))) {
/* If we run with a TX queue, check if the queue is too long*/
txq = netdev_get_tx_queue(skb->dev, 0);
qlen = qdisc_qlen(rcu_dereference_bh(txq->qdisc));
if (likely(qlen == 0))
goto noxoff;
high = (caifd->netdev->tx_queue_len * q_high) / 100;
if (likely(qlen < high))
goto noxoff;
}
/* Hold lock while accessing xoff */
spin_lock_bh(&caifd->flow_lock);
if (caifd->xoff) {
spin_unlock_bh(&caifd->flow_lock);
goto noxoff;
}
/*
* Handle flow off, we do this by temporary hi-jacking this
* skb's destructor function, and replace it with our own
* flow-on callback. The callback will set flow-on and call
* the original destructor.
*/
pr_debug("queue has stopped(%d) or is full (%d > %d)\n",
netif_queue_stopped(caifd->netdev),
qlen, high);
caifd->xoff = 1;
caifd->xoff_skb = skb;
caifd->xoff_skb_dtor = skb->destructor;
skb->destructor = caif_flow_cb;
spin_unlock_bh(&caifd->flow_lock);
caifd->layer.up->ctrlcmd(caifd->layer.up,
_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
caifd->layer.id);
noxoff:
rcu_read_unlock_bh();
err = dev_queue_xmit(skb);
if (err > 0)
err = -EIO;
return err;
}
/*
* Stuff received packets into the CAIF stack.
* On error, returns non-zero and releases the skb.
*/
static int receive(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pkttype, struct net_device *orig_dev)
{
struct cfpkt *pkt;
struct caif_device_entry *caifd;
int err;
pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
rcu_read_lock();
caifd = caif_get(dev);
if (!caifd || !caifd->layer.up || !caifd->layer.up->receive ||
!netif_oper_up(caifd->netdev)) {
rcu_read_unlock();
kfree_skb(skb);
return NET_RX_DROP;
}
/* Hold reference to netdevice while using CAIF stack */
caifd_hold(caifd);
rcu_read_unlock();
err = caifd->layer.up->receive(caifd->layer.up, pkt);
/* For -EILSEQ the packet is not freed so so it now */
if (err == -EILSEQ)
cfpkt_destroy(pkt);
/* Release reference to stack upwards */
caifd_put(caifd);
if (err != 0)
err = NET_RX_DROP;
return err;
}
static struct packet_type caif_packet_type __read_mostly = {
.type = cpu_to_be16(ETH_P_CAIF),
.func = receive,
};
static void dev_flowctrl(struct net_device *dev, int on)
{
struct caif_device_entry *caifd;
rcu_read_lock();
caifd = caif_get(dev);
if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
rcu_read_unlock();
return;
}
caifd_hold(caifd);
rcu_read_unlock();
caifd->layer.up->ctrlcmd(caifd->layer.up,
on ?
_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
caifd->layer.id);
caifd_put(caifd);
}
void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
struct cflayer *link_support, int head_room,
struct cflayer **layer,
int (**rcv_func)(struct sk_buff *, struct net_device *,
struct packet_type *,
struct net_device *))
{
struct caif_device_entry *caifd;
enum cfcnfg_phy_preference pref;
struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
struct caif_device_entry_list *caifdevs;
caifdevs = caif_device_list(dev_net(dev));
caifd = caif_device_alloc(dev);
if (!caifd)
return;
*layer = &caifd->layer;
spin_lock_init(&caifd->flow_lock);
switch (caifdev->link_select) {
case CAIF_LINK_HIGH_BANDW:
pref = CFPHYPREF_HIGH_BW;
break;
case CAIF_LINK_LOW_LATENCY:
pref = CFPHYPREF_LOW_LAT;
break;
default:
pref = CFPHYPREF_HIGH_BW;
break;
}
mutex_lock(&caifdevs->lock);
list_add_rcu(&caifd->list, &caifdevs->list);
strncpy(caifd->layer.name, dev->name,
sizeof(caifd->layer.name) - 1);
caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
caifd->layer.transmit = transmit;
cfcnfg_add_phy_layer(cfg,
dev,
&caifd->layer,
pref,
link_support,
caifdev->use_fcs,
head_room);
mutex_unlock(&caifdevs->lock);
if (rcv_func)
*rcv_func = receive;
}
EXPORT_SYMBOL(caif_enroll_dev);
/* notify Caif of device events */
static int caif_device_notify(struct notifier_block *me, unsigned long what,
void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct caif_device_entry *caifd = NULL;
struct caif_dev_common *caifdev;
struct cfcnfg *cfg;
struct cflayer *layer, *link_support;
int head_room = 0;
struct caif_device_entry_list *caifdevs;
cfg = get_cfcnfg(dev_net(dev));
caifdevs = caif_device_list(dev_net(dev));
caifd = caif_get(dev);
if (caifd == NULL && dev->type != ARPHRD_CAIF)
return 0;
switch (what) {
case NETDEV_REGISTER:
if (caifd != NULL)
break;
caifdev = netdev_priv(dev);
link_support = NULL;
if (caifdev->use_frag) {
head_room = 1;
link_support = cfserl_create(dev->ifindex,
caifdev->use_stx);
if (!link_support) {
pr_warn("Out of memory\n");
break;
}
}
caif_enroll_dev(dev, caifdev, link_support, head_room,
&layer, NULL);
caifdev->flowctrl = dev_flowctrl;
break;
case NETDEV_UP:
rcu_read_lock();
caifd = caif_get(dev);
if (caifd == NULL) {
rcu_read_unlock();
break;
}
caifd->xoff = 0;
cfcnfg_set_phy_state(cfg, &caifd->layer, true);
rcu_read_unlock();
break;
case NETDEV_DOWN:
rcu_read_lock();
caifd = caif_get(dev);
if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
rcu_read_unlock();
return -EINVAL;
}
cfcnfg_set_phy_state(cfg, &caifd->layer, false);
caifd_hold(caifd);
rcu_read_unlock();
caifd->layer.up->ctrlcmd(caifd->layer.up,
_CAIF_CTRLCMD_PHYIF_DOWN_IND,
caifd->layer.id);
spin_lock_bh(&caifd->flow_lock);
/*
* Replace our xoff-destructor with original destructor.
* We trust that skb->destructor *always* is called before
* the skb reference is invalid. The hijacked SKB destructor
* takes the flow_lock so manipulating the skb->destructor here
* should be safe.
*/
if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL)
caifd->xoff_skb->destructor = caifd->xoff_skb_dtor;
caifd->xoff = 0;
caifd->xoff_skb_dtor = NULL;
caifd->xoff_skb = NULL;
spin_unlock_bh(&caifd->flow_lock);
caifd_put(caifd);
break;
case NETDEV_UNREGISTER:
mutex_lock(&caifdevs->lock);
caifd = caif_get(dev);
if (caifd == NULL) {
mutex_unlock(&caifdevs->lock);
break;
}
list_del_rcu(&caifd->list);
/*
* NETDEV_UNREGISTER is called repeatedly until all reference
* counts for the net-device are released. If references to
* caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
* the next call to NETDEV_UNREGISTER.
*
* If any packets are in flight down the CAIF Stack,
* cfcnfg_del_phy_layer will return nonzero.
* If no packets are in flight, the CAIF Stack associated
* with the net-device un-registering is freed.
*/
if (caifd_refcnt_read(caifd) != 0 ||
cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
pr_info("Wait for device inuse\n");
/* Enrole device if CAIF Stack is still in use */
list_add_rcu(&caifd->list, &caifdevs->list);
mutex_unlock(&caifdevs->lock);
break;
}
synchronize_rcu();
dev_put(caifd->netdev);
free_percpu(caifd->pcpu_refcnt);
kfree(caifd);
mutex_unlock(&caifdevs->lock);
break;
}
return 0;
}
static struct notifier_block caif_device_notifier = {
.notifier_call = caif_device_notify,
.priority = 0,
};
/* Per-namespace Caif devices handling */
static int caif_init_net(struct net *net)
{
struct caif_net *caifn = net_generic(net, caif_net_id);
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_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);