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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * CAIF Interface registration.
 * Copyright (C) ST-Ericsson AB 2010
 * Author:	Sjur Brendeland
 *
 * 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 unsigned 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,
				lockdep_rtnl_is_held()) {
		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) {
		rcu_read_unlock();
		return;
	}

	caifd_hold(caifd);
	rcu_read_unlock();

	spin_lock_bh(&caifd->flow_lock);
	send_xoff = caifd->xoff;
	caifd->xoff = false;
	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))) {
		struct Qdisc *sch;

		/* If we run with a TX queue, check if the queue is too long*/
		txq = netdev_get_tx_queue(skb->dev, 0);
		sch = rcu_dereference_bh(txq->qdisc);
		if (likely(qdisc_is_empty(sch)))
			goto noxoff;

		/* can check for explicit qdisc len value only !NOLOCK,
		 * always set flow off otherwise
		 */
		high = (caifd->netdev->tx_queue_len * q_high) / 100;
		if (!(sch->flags & TCQ_F_NOLOCK) && likely(sch->q.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 = true;
	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);
}

int 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;
	int res;

	caifdevs = caif_device_list(dev_net(dev));
	caifd = caif_device_alloc(dev);
	if (!caifd)
		return -ENOMEM;
	*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);

	strlcpy(caifd->layer.name, dev->name,
		sizeof(caifd->layer.name));
	caifd->layer.transmit = transmit;
	res = 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;
	return res;
}
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 = false;
		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 = false;
		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);
Commit	Line	Data
af873fce	1	// SPDX-License-Identifier: GPL-2.0-only
c72dfae2 SB	2	/*
	3	* CAIF Interface registration.
	4	* Copyright (C) ST-Ericsson AB 2010
26ee65e6	5	* Author: Sjur Brendeland
c72dfae2	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	24	#include <net/caif/caif_layer.h>
8203274e	25	#include <net/caif/caif_dev.h>
c72dfae2 SB	26	#include <net/caif/cfpkt.h>
c72dfae2 SB	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
c7d03a00	55	static unsigned 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	{
c72dfae2	94	struct caif_device_entry *caifd;
bd30ce4b	95
4fb66b82	96	caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
c72dfae2 SB	97	if (!caifd)
c72dfae2 SB	98	return NULL;
bd30ce4b	99	caifd->pcpu_refcnt = alloc_percpu(int);
4fb66b82 ED	100	if (!caifd->pcpu_refcnt) {
	101	kfree(caifd);
	102	return NULL;
	103	}
c72dfae2	104	caifd->netdev = dev;
bd30ce4b	105	dev_hold(dev);
c72dfae2 SB	106	return caifd;
	107	}
	108
	109	static struct caif_device_entry caif_get(struct net_device dev)
	110	{
	111	struct caif_device_entry_list *caifdevs =
	112	caif_device_list(dev_net(dev));
	113	struct caif_device_entry *caifd;
7c18d220	114
f9fc28a8 AG	115	list_for_each_entry_rcu(caifd, &caifdevs->list, list,
f9fc28a8 AG	116	lockdep_rtnl_is_held()) {
c72dfae2 SB	117	if (caifd->netdev == dev)
	118	return caifd;
	119	}
	120	return NULL;
	121	}
	122
d6e89c0b	123	static void caif_flow_cb(struct sk_buff *skb)
0e4c7d85	124	{
0e4c7d85	125	struct caif_device_entry *caifd;
7d311304	126	void (dtor)(struct sk_buff skb) = NULL;
0e4c7d85	127	bool send_xoff;
	128
	129	WARN_ON(skb->dev == NULL);
	130
	131	rcu_read_lock();
	132	caifd = caif_get(skb->dev);
c95567c8 KLX	133
c95567c8 KLX	134	WARN_ON(caifd == NULL);
64119e05 Y	135	if (!caifd) {
64119e05 Y	136	rcu_read_unlock();
c95567c8	137	return;
64119e05	138	}
c95567c8	139
0e4c7d85	140	caifd_hold(caifd);
	141	rcu_read_unlock();
	142
	143	spin_lock_bh(&caifd->flow_lock);
	144	send_xoff = caifd->xoff;
8518307d	145	caifd->xoff = false;
59f608d8	146	dtor = caifd->xoff_skb_dtor;
	147
	148	if (WARN_ON(caifd->xoff_skb != skb))
	149	skb = NULL;
	150
	151	caifd->xoff_skb = NULL;
	152	caifd->xoff_skb_dtor = NULL;
	153
0e4c7d85	154	spin_unlock_bh(&caifd->flow_lock);
0e4c7d85	155
59f608d8	156	if (dtor && skb)
7d311304	157	dtor(skb);
7d311304	158
0e4c7d85	159	if (send_xoff)
	160	caifd->layer.up->
	161	ctrlcmd(caifd->layer.up,
	162	_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
	163	caifd->layer.id);
	164	caifd_put(caifd);
	165	}
	166
c72dfae2 SB	167	static int transmit(struct cflayer layer, struct cfpkt pkt)
c72dfae2 SB	168	{
0e4c7d85	169	int err, high = 0, qlen = 0;
c72dfae2 SB	170	struct caif_device_entry *caifd =
c72dfae2 SB	171	container_of(layer, struct caif_device_entry, layer);
4dd820c0	172	struct sk_buff *skb;
0e4c7d85	173	struct netdev_queue *txq;
	174
	175	rcu_read_lock_bh();
4dd820c0	176
c72dfae2 SB	177	skb = cfpkt_tonative(pkt);
c72dfae2 SB	178	skb->dev = caifd->netdev;
7c18d220	179	skb_reset_network_header(skb);
7c18d220	180	skb->protocol = htons(ETH_P_CAIF);
0e4c7d85	181
0e4c7d85	182	/* Check if we need to handle xoff */
4676a152	183	if (likely(caifd->netdev->priv_flags & IFF_NO_QUEUE))
0e4c7d85	184	goto noxoff;
	185
	186	if (unlikely(caifd->xoff))
	187	goto noxoff;
	188
	189	if (likely(!netif_queue_stopped(caifd->netdev))) {
b0a231a2 PA	190	struct Qdisc *sch;
b0a231a2 PA	191
0e4c7d85	192	/* If we run with a TX queue, check if the queue is too long*/
0e4c7d85	193	txq = netdev_get_tx_queue(skb->dev, 0);
b0a231a2 PA	194	sch = rcu_dereference_bh(txq->qdisc);
b0a231a2 PA	195	if (likely(qdisc_is_empty(sch)))
0e4c7d85	196	goto noxoff;
0e4c7d85	197
b0a231a2 PA	198	/* can check for explicit qdisc len value only !NOLOCK,
	199	* always set flow off otherwise
	200	*/
0e4c7d85	201	high = (caifd->netdev->tx_queue_len * q_high) / 100;
b0a231a2	202	if (!(sch->flags & TCQ_F_NOLOCK) && likely(sch->q.qlen < high))
0e4c7d85	203	goto noxoff;
	204	}
	205
	206	/* Hold lock while accessing xoff */
	207	spin_lock_bh(&caifd->flow_lock);
	208	if (caifd->xoff) {
	209	spin_unlock_bh(&caifd->flow_lock);
	210	goto noxoff;
	211	}
	212
	213	/*
	214	* Handle flow off, we do this by temporary hi-jacking this
	215	* skb's destructor function, and replace it with our own
	216	* flow-on callback. The callback will set flow-on and call
	217	* the original destructor.
	218	*/
	219
	220	pr_debug("queue has stopped(%d) or is full (%d > %d)\n",
	221	netif_queue_stopped(caifd->netdev),
	222	qlen, high);
8518307d	223	caifd->xoff = true;
7d311304	224	caifd->xoff_skb = skb;
	225	caifd->xoff_skb_dtor = skb->destructor;
	226	skb->destructor = caif_flow_cb;
0e4c7d85	227	spin_unlock_bh(&caifd->flow_lock);
0e4c7d85	228
	229	caifd->layer.up->ctrlcmd(caifd->layer.up,
	230	_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
	231	caifd->layer.id);
	232	noxoff:
	233	rcu_read_unlock_bh();
4dd820c0	234
c85c2951	235	err = dev_queue_xmit(skb);
	236	if (err > 0)
	237	err = -EIO;
c72dfae2	238
c85c2951	239	return err;
c72dfae2 SB	240	}
c72dfae2 SB	241
c72dfae2	242	/*
bd30ce4b	243	* Stuff received packets into the CAIF stack.
c72dfae2 SB	244	* On error, returns non-zero and releases the skb.
	245	*/
	246	static int receive(struct sk_buff skb, struct net_device dev,
	247	struct packet_type pkttype, struct net_device orig_dev)
	248	{
c72dfae2 SB	249	struct cfpkt *pkt;
c72dfae2 SB	250	struct caif_device_entry *caifd;
69c867c9	251	int err;
bd30ce4b	252
c72dfae2	253	pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
bd30ce4b	254
bd30ce4b	255	rcu_read_lock();
c72dfae2	256	caifd = caif_get(dev);
c72dfae2	257
bd30ce4b	258	if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->receive \|\|
	259	!netif_oper_up(caifd->netdev)) {
	260	rcu_read_unlock();
	261	kfree_skb(skb);
c72dfae2	262	return NET_RX_DROP;
bd30ce4b	263	}
	264
	265	/* Hold reference to netdevice while using CAIF stack */
	266	caifd_hold(caifd);
	267	rcu_read_unlock();
c72dfae2	268
69c867c9	269	err = caifd->layer.up->receive(caifd->layer.up, pkt);
	270
	271	/* For -EILSEQ the packet is not freed so so it now */
	272	if (err == -EILSEQ)
	273	cfpkt_destroy(pkt);
bd30ce4b	274
	275	/* Release reference to stack upwards */
	276	caifd_put(caifd);
7c18d220	277
	278	if (err != 0)
	279	err = NET_RX_DROP;
	280	return err;
c72dfae2 SB	281	}
	282
	283	static struct packet_type caif_packet_type __read_mostly = {
	284	.type = cpu_to_be16(ETH_P_CAIF),
	285	.func = receive,
	286	};
	287
	288	static void dev_flowctrl(struct net_device *dev, int on)
	289	{
bd30ce4b	290	struct caif_device_entry *caifd;
	291
	292	rcu_read_lock();
	293
	294	caifd = caif_get(dev);
	295	if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->ctrlcmd) {
	296	rcu_read_unlock();
c72dfae2	297	return;
bd30ce4b	298	}
	299
	300	caifd_hold(caifd);
	301	rcu_read_unlock();
c72dfae2 SB	302
	303	caifd->layer.up->ctrlcmd(caifd->layer.up,
	304	on ?
	305	_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
	306	_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
	307	caifd->layer.id);
bd30ce4b	308	caifd_put(caifd);
c72dfae2 SB	309	}
c72dfae2 SB	310
c20c5f67	311	int caif_enroll_dev(struct net_device dev, struct caif_dev_common caifdev,
3bffc475 SMP	312	struct cflayer *link_support, int head_room,
	313	struct cflayer **layer,
	314	int (*rcv_func)(struct sk_buff , struct net_device *,
	315	struct packet_type *,
	316	struct net_device *))
7c18d220	317	{
	318	struct caif_device_entry *caifd;
	319	enum cfcnfg_phy_preference pref;
	320	struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
	321	struct caif_device_entry_list *caifdevs;
c20c5f67	322	int res;
7c18d220	323
7c18d220	324	caifdevs = caif_device_list(dev_net(dev));
7c18d220	325	caifd = caif_device_alloc(dev);
7c18d220	326	if (!caifd)
c20c5f67	327	return -ENOMEM;
7c18d220	328	*layer = &caifd->layer;
0e4c7d85	329	spin_lock_init(&caifd->flow_lock);
7c18d220	330
	331	switch (caifdev->link_select) {
	332	case CAIF_LINK_HIGH_BANDW:
	333	pref = CFPHYPREF_HIGH_BW;
	334	break;
	335	case CAIF_LINK_LOW_LATENCY:
	336	pref = CFPHYPREF_LOW_LAT;
	337	break;
	338	default:
	339	pref = CFPHYPREF_HIGH_BW;
	340	break;
	341	}
	342	mutex_lock(&caifdevs->lock);
	343	list_add_rcu(&caifd->list, &caifdevs->list);
	344
3dc2fa47 XW	345	strlcpy(caifd->layer.name, dev->name,
3dc2fa47 XW	346	sizeof(caifd->layer.name));
7c18d220	347	caifd->layer.transmit = transmit;
c20c5f67	348	res = cfcnfg_add_phy_layer(cfg,
7c18d220	349	dev,
	350	&caifd->layer,
	351	pref,
	352	link_support,
	353	caifdev->use_fcs,
	354	head_room);
	355	mutex_unlock(&caifdevs->lock);
	356	if (rcv_func)
	357	*rcv_func = receive;
c20c5f67	358	return res;
7c18d220	359	}
7ad65bf6	360	EXPORT_SYMBOL(caif_enroll_dev);
7c18d220	361
c72dfae2 SB	362	/* notify Caif of device events */
c72dfae2 SB	363	static int caif_device_notify(struct notifier_block *me, unsigned long what,
351638e7	364	void *ptr)
c72dfae2	365	{
351638e7	366	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
c72dfae2 SB	367	struct caif_device_entry *caifd = NULL;
c72dfae2 SB	368	struct caif_dev_common *caifdev;
bee925db	369	struct cfcnfg *cfg;
7c18d220	370	struct cflayer layer, link_support;
7c18d220	371	int head_room = 0;
08613e46	372	struct caif_device_entry_list *caifdevs;
c72dfae2	373
bee925db	374	cfg = get_cfcnfg(dev_net(dev));
7c18d220	375	caifdevs = caif_device_list(dev_net(dev));
bee925db	376
7c18d220	377	caifd = caif_get(dev);
	378	if (caifd == NULL && dev->type != ARPHRD_CAIF)
	379	return 0;
08613e46	380
c72dfae2 SB	381	switch (what) {
c72dfae2 SB	382	case NETDEV_REGISTER:
7c18d220	383	if (caifd != NULL)
7c18d220	384	break;
bd30ce4b	385
c72dfae2	386	caifdev = netdev_priv(dev);
c72dfae2	387
7c18d220	388	link_support = NULL;
	389	if (caifdev->use_frag) {
	390	head_room = 1;
	391	link_support = cfserl_create(dev->ifindex,
e977b4cf	392	caifdev->use_stx);
7c18d220	393	if (!link_support) {
	394	pr_warn("Out of memory\n");
	395	break;
	396	}
c72dfae2	397	}
7c18d220	398	caif_enroll_dev(dev, caifdev, link_support, head_room,
	399	&layer, NULL);
	400	caifdev->flowctrl = dev_flowctrl;
c72dfae2 SB	401	break;
c72dfae2 SB	402
bd30ce4b	403	case NETDEV_UP:
	404	rcu_read_lock();
	405
c72dfae2	406	caifd = caif_get(dev);
bd30ce4b	407	if (caifd == NULL) {
bd30ce4b	408	rcu_read_unlock();
c72dfae2	409	break;
bd30ce4b	410	}
c72dfae2	411
8518307d	412	caifd->xoff = false;
bd30ce4b	413	cfcnfg_set_phy_state(cfg, &caifd->layer, true);
bd30ce4b	414	rcu_read_unlock();
c72dfae2	415
c72dfae2 SB	416	break;
	417
	418	case NETDEV_DOWN:
bd30ce4b	419	rcu_read_lock();
bd30ce4b	420
c72dfae2	421	caifd = caif_get(dev);
bd30ce4b	422	if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->ctrlcmd) {
	423	rcu_read_unlock();
	424	return -EINVAL;
	425	}
	426
	427	cfcnfg_set_phy_state(cfg, &caifd->layer, false);
	428	caifd_hold(caifd);
	429	rcu_read_unlock();
	430
	431	caifd->layer.up->ctrlcmd(caifd->layer.up,
	432	_CAIF_CTRLCMD_PHYIF_DOWN_IND,
	433	caifd->layer.id);
7d311304	434
	435	spin_lock_bh(&caifd->flow_lock);
	436
	437	/*
	438	* Replace our xoff-destructor with original destructor.
	439	* We trust that skb->destructor always is called before
	440	* the skb reference is invalid. The hijacked SKB destructor
	441	* takes the flow_lock so manipulating the skb->destructor here
	442	* should be safe.
	443	*/
	444	if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL)
	445	caifd->xoff_skb->destructor = caifd->xoff_skb_dtor;
	446
8518307d	447	caifd->xoff = false;
7d311304	448	caifd->xoff_skb_dtor = NULL;
	449	caifd->xoff_skb = NULL;
	450
	451	spin_unlock_bh(&caifd->flow_lock);
bd30ce4b	452	caifd_put(caifd);
c72dfae2 SB	453	break;
	454
	455	case NETDEV_UNREGISTER:
bd30ce4b	456	mutex_lock(&caifdevs->lock);
bd30ce4b	457
c72dfae2	458	caifd = caif_get(dev);
bd30ce4b	459	if (caifd == NULL) {
bd30ce4b	460	mutex_unlock(&caifdevs->lock);
f2527ec4	461	break;
bd30ce4b	462	}
	463	list_del_rcu(&caifd->list);
	464
	465	/*
	466	* NETDEV_UNREGISTER is called repeatedly until all reference
	467	* counts for the net-device are released. If references to
	468	* caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
	469	* the next call to NETDEV_UNREGISTER.
	470	*
	471	* If any packets are in flight down the CAIF Stack,
	472	* cfcnfg_del_phy_layer will return nonzero.
	473	* If no packets are in flight, the CAIF Stack associated
	474	* with the net-device un-registering is freed.
	475	*/
	476
	477	if (caifd_refcnt_read(caifd) != 0 \|\|
	478	cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
	479
	480	pr_info("Wait for device inuse\n");
	481	/* Enrole device if CAIF Stack is still in use */
	482	list_add_rcu(&caifd->list, &caifdevs->list);
	483	mutex_unlock(&caifdevs->lock);
	484	break;
	485	}
	486
	487	synchronize_rcu();
	488	dev_put(caifd->netdev);
	489	free_percpu(caifd->pcpu_refcnt);
	490	kfree(caifd);
	491
	492	mutex_unlock(&caifdevs->lock);
c72dfae2 SB	493	break;
	494	}
	495	return 0;
	496	}
	497
	498	static struct notifier_block caif_device_notifier = {
	499	.notifier_call = caif_device_notify,
	500	.priority = 0,
	501	};
	502
c72dfae2 SB	503	/* Per-namespace Caif devices handling */
	504	static int caif_init_net(struct net *net)
	505	{
	506	struct caif_net *caifn = net_generic(net, caif_net_id);
	507	INIT_LIST_HEAD(&caifn->caifdevs.list);
bd30ce4b	508	mutex_init(&caifn->caifdevs.lock);
bee925db	509
bee925db	510	caifn->cfg = cfcnfg_create();
f84ea779	511	if (!caifn->cfg)
bee925db	512	return -ENOMEM;
bee925db	513
c72dfae2 SB	514	return 0;
	515	}
	516
	517	static void caif_exit_net(struct net *net)
	518	{
bd30ce4b	519	struct caif_device_entry caifd, tmp;
	520	struct caif_device_entry_list *caifdevs =
	521	caif_device_list(net);
7c18d220	522	struct cfcnfg *cfg = get_cfcnfg(net);
7c18d220	523
c72dfae2	524	rtnl_lock();
bd30ce4b	525	mutex_lock(&caifdevs->lock);
	526
	527	list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
	528	int i = 0;
	529	list_del_rcu(&caifd->list);
	530	cfcnfg_set_phy_state(cfg, &caifd->layer, false);
	531
	532	while (i < 10 &&
	533	(caifd_refcnt_read(caifd) != 0 \|\|
	534	cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
	535
	536	pr_info("Wait for device inuse\n");
	537	msleep(250);
	538	i++;
	539	}
	540	synchronize_rcu();
	541	dev_put(caifd->netdev);
	542	free_percpu(caifd->pcpu_refcnt);
	543	kfree(caifd);
c72dfae2	544	}
bee925db	545	cfcnfg_remove(cfg);
bd30ce4b	546
bd30ce4b	547	mutex_unlock(&caifdevs->lock);
c72dfae2 SB	548	rtnl_unlock();
	549	}
	550
	551	static struct pernet_operations caif_net_ops = {
	552	.init = caif_init_net,
	553	.exit = caif_exit_net,
	554	.id = &caif_net_id,
	555	.size = sizeof(struct caif_net),
	556	};
	557
	558	/* Initialize Caif devices list */
	559	static int __init caif_device_init(void)
	560	{
	561	int result;
bd30ce4b	562
8a8ee9af	563	result = register_pernet_subsys(&caif_net_ops);
c72dfae2	564
bee925db	565	if (result)
c72dfae2	566	return result;
bee925db	567
c72dfae2	568	register_netdevice_notifier(&caif_device_notifier);
bee925db	569	dev_add_pack(&caif_packet_type);
c72dfae2 SB	570
c72dfae2 SB	571	return result;
c72dfae2 SB	572	}
	573
	574	static void __exit caif_device_exit(void)
	575	{
c72dfae2	576	unregister_netdevice_notifier(&caif_device_notifier);
bee925db	577	dev_remove_pack(&caif_packet_type);
96f80d12	578	unregister_pernet_subsys(&caif_net_ops);
c72dfae2 SB	579	}
	580
	581	module_init(caif_device_init);
	582	module_exit(caif_device_exit);