[mirror_ubuntu-artful-kernel.git] / net / caif / caif_dev.c

/*
 * CAIF Interface registration.
 * Copyright (C) ST-Ericsson AB 2010
 * Author:	Sjur Brendeland/sjur.brandeland@stericsson.com
 * 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/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_list *caifdevs;
	struct caif_device_entry *caifd;

	caifdevs = caif_device_list(dev_net(dev));

	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;
}

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);
	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->tx_queue_len == 0))
		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 *arg)
{
	struct net_device *dev = arg;
	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_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);
Commit	Line	Data
c72dfae2 SB	1	/*
	2	* CAIF Interface registration.
	3	* Copyright (C) ST-Ericsson AB 2010
	4	* Author: Sjur Brendeland/sjur.brandeland@stericsson.com
	5	* License terms: GNU General Public License (GPL) version 2
	6	*
31fdc555	7	* Borrowed heavily from file: pn_dev.c. Thanks to Remi Denis-Courmont
c72dfae2 SB	8	* and Sakari Ailus <sakari.ailus@nokia.com>
	9	*/
	10
b31fa5ba JP	11	#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
b31fa5ba JP	12
c72dfae2 SB	13	#include <linux/kernel.h>
	14	#include <linux/if_arp.h>
	15	#include <linux/net.h>
	16	#include <linux/netdevice.h>
bd30ce4b	17	#include <linux/mutex.h>
3a9a231d	18	#include <linux/module.h>
0e4c7d85	19	#include <linux/spinlock.h>
c72dfae2 SB	20	#include <net/netns/generic.h>
	21	#include <net/net_namespace.h>
	22	#include <net/pkt_sched.h>
	23	#include <net/caif/caif_device.h>
c72dfae2 SB	24	#include <net/caif/caif_layer.h>
	25	#include <net/caif/cfpkt.h>
	26	#include <net/caif/cfcnfg.h>
7c18d220	27	#include <net/caif/cfserl.h>
c72dfae2 SB	28
c72dfae2 SB	29	MODULE_LICENSE("GPL");
c72dfae2 SB	30
	31	/* Used for local tracking of the CAIF net devices */
	32	struct caif_device_entry {
	33	struct cflayer layer;
	34	struct list_head list;
c72dfae2	35	struct net_device *netdev;
bd30ce4b	36	int __percpu *pcpu_refcnt;
0e4c7d85	37	spinlock_t flow_lock;
7d311304	38	struct sk_buff *xoff_skb;
7d311304	39	void (xoff_skb_dtor)(struct sk_buff skb);
0e4c7d85	40	bool xoff;
c72dfae2 SB	41	};
	42
	43	struct caif_device_entry_list {
	44	struct list_head list;
	45	/* Protects simulanous deletes in list */
bd30ce4b	46	struct mutex lock;
c72dfae2 SB	47	};
	48
	49	struct caif_net {
bee925db	50	struct cfcnfg *cfg;
c72dfae2 SB	51	struct caif_device_entry_list caifdevs;
	52	};
	53
	54	static int caif_net_id;
0e4c7d85	55	static int q_high = 50; /* Percent */
bee925db	56
	57	struct cfcnfg get_cfcnfg(struct net net)
	58	{
	59	struct caif_net *caifn;
bee925db	60	caifn = net_generic(net, caif_net_id);
bee925db	61	return caifn->cfg;
	62	}
	63	EXPORT_SYMBOL(get_cfcnfg);
c72dfae2 SB	64
	65	static struct caif_device_entry_list caif_device_list(struct net net)
	66	{
	67	struct caif_net *caifn;
c72dfae2	68	caifn = net_generic(net, caif_net_id);
c72dfae2 SB	69	return &caifn->caifdevs;
	70	}
	71
bd30ce4b	72	static void caifd_put(struct caif_device_entry *e)
bd30ce4b	73	{
933393f5	74	this_cpu_dec(*e->pcpu_refcnt);
bd30ce4b	75	}
	76
	77	static void caifd_hold(struct caif_device_entry *e)
	78	{
933393f5	79	this_cpu_inc(*e->pcpu_refcnt);
bd30ce4b	80	}
	81
	82	static int caifd_refcnt_read(struct caif_device_entry *e)
	83	{
	84	int i, refcnt = 0;
	85	for_each_possible_cpu(i)
	86	refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
	87	return refcnt;
	88	}
	89
c72dfae2 SB	90	/* Allocate new CAIF device. */
	91	static struct caif_device_entry caif_device_alloc(struct net_device dev)
	92	{
	93	struct caif_device_entry_list *caifdevs;
	94	struct caif_device_entry *caifd;
bd30ce4b	95
c72dfae2	96	caifdevs = caif_device_list(dev_net(dev));
bd30ce4b	97
4fb66b82	98	caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
c72dfae2 SB	99	if (!caifd)
c72dfae2 SB	100	return NULL;
bd30ce4b	101	caifd->pcpu_refcnt = alloc_percpu(int);
4fb66b82 ED	102	if (!caifd->pcpu_refcnt) {
	103	kfree(caifd);
	104	return NULL;
	105	}
c72dfae2	106	caifd->netdev = dev;
bd30ce4b	107	dev_hold(dev);
c72dfae2 SB	108	return caifd;
	109	}
	110
	111	static struct caif_device_entry caif_get(struct net_device dev)
	112	{
	113	struct caif_device_entry_list *caifdevs =
	114	caif_device_list(dev_net(dev));
	115	struct caif_device_entry *caifd;
7c18d220	116
bd30ce4b	117	list_for_each_entry_rcu(caifd, &caifdevs->list, list) {
c72dfae2 SB	118	if (caifd->netdev == dev)
	119	return caifd;
	120	}
	121	return NULL;
	122	}
	123
0e4c7d85	124	void caif_flow_cb(struct sk_buff *skb)
	125	{
	126	struct caif_device_entry *caifd;
7d311304	127	void (dtor)(struct sk_buff skb) = NULL;
0e4c7d85	128	bool send_xoff;
	129
	130	WARN_ON(skb->dev == NULL);
	131
	132	rcu_read_lock();
	133	caifd = caif_get(skb->dev);
	134	caifd_hold(caifd);
	135	rcu_read_unlock();
	136
	137	spin_lock_bh(&caifd->flow_lock);
	138	send_xoff = caifd->xoff;
	139	caifd->xoff = 0;
59f608d8	140	dtor = caifd->xoff_skb_dtor;
	141
	142	if (WARN_ON(caifd->xoff_skb != skb))
	143	skb = NULL;
	144
	145	caifd->xoff_skb = NULL;
	146	caifd->xoff_skb_dtor = NULL;
	147
0e4c7d85	148	spin_unlock_bh(&caifd->flow_lock);
0e4c7d85	149
59f608d8	150	if (dtor && skb)
7d311304	151	dtor(skb);
7d311304	152
0e4c7d85	153	if (send_xoff)
	154	caifd->layer.up->
	155	ctrlcmd(caifd->layer.up,
	156	_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
	157	caifd->layer.id);
	158	caifd_put(caifd);
	159	}
	160
c72dfae2 SB	161	static int transmit(struct cflayer layer, struct cfpkt pkt)
c72dfae2 SB	162	{
0e4c7d85	163	int err, high = 0, qlen = 0;
c72dfae2 SB	164	struct caif_device_entry *caifd =
c72dfae2 SB	165	container_of(layer, struct caif_device_entry, layer);
4dd820c0	166	struct sk_buff *skb;
0e4c7d85	167	struct netdev_queue *txq;
	168
	169	rcu_read_lock_bh();
4dd820c0	170
c72dfae2 SB	171	skb = cfpkt_tonative(pkt);
c72dfae2 SB	172	skb->dev = caifd->netdev;
7c18d220	173	skb_reset_network_header(skb);
7c18d220	174	skb->protocol = htons(ETH_P_CAIF);
0e4c7d85	175
	176	/* Check if we need to handle xoff */
	177	if (likely(caifd->netdev->tx_queue_len == 0))
	178	goto noxoff;
	179
	180	if (unlikely(caifd->xoff))
	181	goto noxoff;
	182
	183	if (likely(!netif_queue_stopped(caifd->netdev))) {
	184	/* If we run with a TX queue, check if the queue is too long*/
	185	txq = netdev_get_tx_queue(skb->dev, 0);
	186	qlen = qdisc_qlen(rcu_dereference_bh(txq->qdisc));
	187
	188	if (likely(qlen == 0))
	189	goto noxoff;
	190
	191	high = (caifd->netdev->tx_queue_len * q_high) / 100;
	192	if (likely(qlen < high))
	193	goto noxoff;
	194	}
	195
	196	/* Hold lock while accessing xoff */
	197	spin_lock_bh(&caifd->flow_lock);
	198	if (caifd->xoff) {
	199	spin_unlock_bh(&caifd->flow_lock);
	200	goto noxoff;
	201	}
	202
	203	/*
	204	* Handle flow off, we do this by temporary hi-jacking this
	205	* skb's destructor function, and replace it with our own
	206	* flow-on callback. The callback will set flow-on and call
	207	* the original destructor.
	208	*/
	209
	210	pr_debug("queue has stopped(%d) or is full (%d > %d)\n",
	211	netif_queue_stopped(caifd->netdev),
	212	qlen, high);
	213	caifd->xoff = 1;
7d311304	214	caifd->xoff_skb = skb;
	215	caifd->xoff_skb_dtor = skb->destructor;
	216	skb->destructor = caif_flow_cb;
0e4c7d85	217	spin_unlock_bh(&caifd->flow_lock);
0e4c7d85	218
	219	caifd->layer.up->ctrlcmd(caifd->layer.up,
	220	_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
	221	caifd->layer.id);
	222	noxoff:
	223	rcu_read_unlock_bh();
4dd820c0	224
c85c2951	225	err = dev_queue_xmit(skb);
	226	if (err > 0)
	227	err = -EIO;
c72dfae2	228
c85c2951	229	return err;
c72dfae2 SB	230	}
c72dfae2 SB	231
c72dfae2	232	/*
bd30ce4b	233	* Stuff received packets into the CAIF stack.
c72dfae2 SB	234	* On error, returns non-zero and releases the skb.
	235	*/
	236	static int receive(struct sk_buff skb, struct net_device dev,
	237	struct packet_type pkttype, struct net_device orig_dev)
	238	{
c72dfae2 SB	239	struct cfpkt *pkt;
c72dfae2 SB	240	struct caif_device_entry *caifd;
69c867c9	241	int err;
bd30ce4b	242
c72dfae2	243	pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
bd30ce4b	244
bd30ce4b	245	rcu_read_lock();
c72dfae2	246	caifd = caif_get(dev);
c72dfae2	247
bd30ce4b	248	if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->receive \|\|
	249	!netif_oper_up(caifd->netdev)) {
	250	rcu_read_unlock();
	251	kfree_skb(skb);
c72dfae2	252	return NET_RX_DROP;
bd30ce4b	253	}
	254
	255	/* Hold reference to netdevice while using CAIF stack */
	256	caifd_hold(caifd);
	257	rcu_read_unlock();
c72dfae2	258
69c867c9	259	err = caifd->layer.up->receive(caifd->layer.up, pkt);
	260
	261	/* For -EILSEQ the packet is not freed so so it now */
	262	if (err == -EILSEQ)
	263	cfpkt_destroy(pkt);
bd30ce4b	264
	265	/* Release reference to stack upwards */
	266	caifd_put(caifd);
7c18d220	267
	268	if (err != 0)
	269	err = NET_RX_DROP;
	270	return err;
c72dfae2 SB	271	}
	272
	273	static struct packet_type caif_packet_type __read_mostly = {
	274	.type = cpu_to_be16(ETH_P_CAIF),
	275	.func = receive,
	276	};
	277
	278	static void dev_flowctrl(struct net_device *dev, int on)
	279	{
bd30ce4b	280	struct caif_device_entry *caifd;
	281
	282	rcu_read_lock();
	283
	284	caifd = caif_get(dev);
	285	if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->ctrlcmd) {
	286	rcu_read_unlock();
c72dfae2	287	return;
bd30ce4b	288	}
	289
	290	caifd_hold(caifd);
	291	rcu_read_unlock();
c72dfae2 SB	292
	293	caifd->layer.up->ctrlcmd(caifd->layer.up,
	294	on ?
	295	_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
	296	_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
	297	caifd->layer.id);
bd30ce4b	298	caifd_put(caifd);
c72dfae2 SB	299	}
c72dfae2 SB	300
7c18d220	301	void caif_enroll_dev(struct net_device dev, struct caif_dev_common caifdev,
	302	struct cflayer *link_support, int head_room,
	303	struct cflayer layer, int (rcv_func)(
	304	struct sk_buff , struct net_device ,
	305	struct packet_type , struct net_device ))
	306	{
	307	struct caif_device_entry *caifd;
	308	enum cfcnfg_phy_preference pref;
	309	struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
	310	struct caif_device_entry_list *caifdevs;
	311
	312	caifdevs = caif_device_list(dev_net(dev));
7c18d220	313	caifd = caif_device_alloc(dev);
	314	if (!caifd)
	315	return;
	316	*layer = &caifd->layer;
0e4c7d85	317	spin_lock_init(&caifd->flow_lock);
7c18d220	318
	319	switch (caifdev->link_select) {
	320	case CAIF_LINK_HIGH_BANDW:
	321	pref = CFPHYPREF_HIGH_BW;
	322	break;
	323	case CAIF_LINK_LOW_LATENCY:
	324	pref = CFPHYPREF_LOW_LAT;
	325	break;
	326	default:
	327	pref = CFPHYPREF_HIGH_BW;
	328	break;
	329	}
	330	mutex_lock(&caifdevs->lock);
	331	list_add_rcu(&caifd->list, &caifdevs->list);
	332
	333	strncpy(caifd->layer.name, dev->name,
	334	sizeof(caifd->layer.name) - 1);
	335	caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
	336	caifd->layer.transmit = transmit;
	337	cfcnfg_add_phy_layer(cfg,
	338	dev,
	339	&caifd->layer,
	340	pref,
	341	link_support,
	342	caifdev->use_fcs,
	343	head_room);
	344	mutex_unlock(&caifdevs->lock);
	345	if (rcv_func)
	346	*rcv_func = receive;
	347	}
7ad65bf6	348	EXPORT_SYMBOL(caif_enroll_dev);
7c18d220	349
c72dfae2 SB	350	/* notify Caif of device events */
	351	static int caif_device_notify(struct notifier_block *me, unsigned long what,
	352	void *arg)
	353	{
	354	struct net_device *dev = arg;
	355	struct caif_device_entry *caifd = NULL;
	356	struct caif_dev_common *caifdev;
bee925db	357	struct cfcnfg *cfg;
7c18d220	358	struct cflayer layer, link_support;
7c18d220	359	int head_room = 0;
08613e46	360	struct caif_device_entry_list *caifdevs;
c72dfae2	361
bee925db	362	cfg = get_cfcnfg(dev_net(dev));
7c18d220	363	caifdevs = caif_device_list(dev_net(dev));
bee925db	364
7c18d220	365	caifd = caif_get(dev);
	366	if (caifd == NULL && dev->type != ARPHRD_CAIF)
	367	return 0;
08613e46	368
c72dfae2 SB	369	switch (what) {
c72dfae2 SB	370	case NETDEV_REGISTER:
7c18d220	371	if (caifd != NULL)
7c18d220	372	break;
bd30ce4b	373
c72dfae2	374	caifdev = netdev_priv(dev);
c72dfae2	375
7c18d220	376	link_support = NULL;
	377	if (caifdev->use_frag) {
	378	head_room = 1;
	379	link_support = cfserl_create(dev->ifindex,
e977b4cf	380	caifdev->use_stx);
7c18d220	381	if (!link_support) {
	382	pr_warn("Out of memory\n");
	383	break;
	384	}
c72dfae2	385	}
7c18d220	386	caif_enroll_dev(dev, caifdev, link_support, head_room,
	387	&layer, NULL);
	388	caifdev->flowctrl = dev_flowctrl;
c72dfae2 SB	389	break;
c72dfae2 SB	390
bd30ce4b	391	case NETDEV_UP:
	392	rcu_read_lock();
	393
c72dfae2	394	caifd = caif_get(dev);
bd30ce4b	395	if (caifd == NULL) {
bd30ce4b	396	rcu_read_unlock();
c72dfae2	397	break;
bd30ce4b	398	}
c72dfae2	399
0e4c7d85	400	caifd->xoff = 0;
bd30ce4b	401	cfcnfg_set_phy_state(cfg, &caifd->layer, true);
bd30ce4b	402	rcu_read_unlock();
c72dfae2	403
c72dfae2 SB	404	break;
	405
	406	case NETDEV_DOWN:
bd30ce4b	407	rcu_read_lock();
bd30ce4b	408
c72dfae2	409	caifd = caif_get(dev);
bd30ce4b	410	if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->ctrlcmd) {
	411	rcu_read_unlock();
	412	return -EINVAL;
	413	}
	414
	415	cfcnfg_set_phy_state(cfg, &caifd->layer, false);
	416	caifd_hold(caifd);
	417	rcu_read_unlock();
	418
	419	caifd->layer.up->ctrlcmd(caifd->layer.up,
	420	_CAIF_CTRLCMD_PHYIF_DOWN_IND,
	421	caifd->layer.id);
7d311304	422
	423	spin_lock_bh(&caifd->flow_lock);
	424
	425	/*
	426	* Replace our xoff-destructor with original destructor.
	427	* We trust that skb->destructor always is called before
	428	* the skb reference is invalid. The hijacked SKB destructor
	429	* takes the flow_lock so manipulating the skb->destructor here
	430	* should be safe.
	431	*/
	432	if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL)
	433	caifd->xoff_skb->destructor = caifd->xoff_skb_dtor;
	434
	435	caifd->xoff = 0;
	436	caifd->xoff_skb_dtor = NULL;
	437	caifd->xoff_skb = NULL;
	438
	439	spin_unlock_bh(&caifd->flow_lock);
bd30ce4b	440	caifd_put(caifd);
c72dfae2 SB	441	break;
	442
	443	case NETDEV_UNREGISTER:
bd30ce4b	444	mutex_lock(&caifdevs->lock);
bd30ce4b	445
c72dfae2	446	caifd = caif_get(dev);
bd30ce4b	447	if (caifd == NULL) {
bd30ce4b	448	mutex_unlock(&caifdevs->lock);
f2527ec4	449	break;
bd30ce4b	450	}
	451	list_del_rcu(&caifd->list);
	452
	453	/*
	454	* NETDEV_UNREGISTER is called repeatedly until all reference
	455	* counts for the net-device are released. If references to
	456	* caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
	457	* the next call to NETDEV_UNREGISTER.
	458	*
	459	* If any packets are in flight down the CAIF Stack,
	460	* cfcnfg_del_phy_layer will return nonzero.
	461	* If no packets are in flight, the CAIF Stack associated
	462	* with the net-device un-registering is freed.
	463	*/
	464
	465	if (caifd_refcnt_read(caifd) != 0 \|\|
	466	cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
	467
	468	pr_info("Wait for device inuse\n");
	469	/* Enrole device if CAIF Stack is still in use */
	470	list_add_rcu(&caifd->list, &caifdevs->list);
	471	mutex_unlock(&caifdevs->lock);
	472	break;
	473	}
	474
	475	synchronize_rcu();
	476	dev_put(caifd->netdev);
	477	free_percpu(caifd->pcpu_refcnt);
	478	kfree(caifd);
	479
	480	mutex_unlock(&caifdevs->lock);
c72dfae2 SB	481	break;
	482	}
	483	return 0;
	484	}
	485
	486	static struct notifier_block caif_device_notifier = {
	487	.notifier_call = caif_device_notify,
	488	.priority = 0,
	489	};
	490
c72dfae2 SB	491	/* Per-namespace Caif devices handling */
	492	static int caif_init_net(struct net *net)
	493	{
	494	struct caif_net *caifn = net_generic(net, caif_net_id);
	495	INIT_LIST_HEAD(&caifn->caifdevs.list);
bd30ce4b	496	mutex_init(&caifn->caifdevs.lock);
bee925db	497
bee925db	498	caifn->cfg = cfcnfg_create();
f84ea779	499	if (!caifn->cfg)
bee925db	500	return -ENOMEM;
bee925db	501
c72dfae2 SB	502	return 0;
	503	}
	504
	505	static void caif_exit_net(struct net *net)
	506	{
bd30ce4b	507	struct caif_device_entry caifd, tmp;
	508	struct caif_device_entry_list *caifdevs =
	509	caif_device_list(net);
7c18d220	510	struct cfcnfg *cfg = get_cfcnfg(net);
7c18d220	511
c72dfae2	512	rtnl_lock();
bd30ce4b	513	mutex_lock(&caifdevs->lock);
	514
	515	list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
	516	int i = 0;
	517	list_del_rcu(&caifd->list);
	518	cfcnfg_set_phy_state(cfg, &caifd->layer, false);
	519
	520	while (i < 10 &&
	521	(caifd_refcnt_read(caifd) != 0 \|\|
	522	cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
	523
	524	pr_info("Wait for device inuse\n");
	525	msleep(250);
	526	i++;
	527	}
	528	synchronize_rcu();
	529	dev_put(caifd->netdev);
	530	free_percpu(caifd->pcpu_refcnt);
	531	kfree(caifd);
c72dfae2	532	}
bee925db	533	cfcnfg_remove(cfg);
bd30ce4b	534
bd30ce4b	535	mutex_unlock(&caifdevs->lock);
c72dfae2 SB	536	rtnl_unlock();
	537	}
	538
	539	static struct pernet_operations caif_net_ops = {
	540	.init = caif_init_net,
	541	.exit = caif_exit_net,
	542	.id = &caif_net_id,
	543	.size = sizeof(struct caif_net),
	544	};
	545
	546	/* Initialize Caif devices list */
	547	static int __init caif_device_init(void)
	548	{
	549	int result;
bd30ce4b	550
8a8ee9af	551	result = register_pernet_subsys(&caif_net_ops);
c72dfae2	552
bee925db	553	if (result)
c72dfae2	554	return result;
bee925db	555
c72dfae2	556	register_netdevice_notifier(&caif_device_notifier);
bee925db	557	dev_add_pack(&caif_packet_type);
c72dfae2 SB	558
c72dfae2 SB	559	return result;
c72dfae2 SB	560	}
	561
	562	static void __exit caif_device_exit(void)
	563	{
8a8ee9af	564	unregister_pernet_subsys(&caif_net_ops);
c72dfae2	565	unregister_netdevice_notifier(&caif_device_notifier);
bee925db	566	dev_remove_pack(&caif_packet_type);
c72dfae2 SB	567	}
	568
	569	module_init(caif_device_init);
	570	module_exit(caif_device_exit);