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