caif: Use RCU instead of spin-lock in caif_dev.c (bd30ce4b) · Commits · 戴 / test

include/net/caif/cfcnfg.h

+10 −0

Original line number	Diff line number	Diff line
		@@ -145,4 +145,14 @@ struct dev_info cfcnfg_get_phyid(struct cfcnfg cnfg,
		* @ifi: ifindex obtained from socket.c bindtodevice.
		*/
		int cfcnfg_get_id_from_ifi(struct cfcnfg *cnfg, int ifi);

		/**
		* cfcnfg_set_phy_state() - Set the state of the physical interface device.
		* @cnfg: Configuration object
		* @phy_layer: Physical Layer representation
		* @up: State of device
		*/
		int cfcnfg_set_phy_state(struct cfcnfg cnfg, struct cflayer phy_layer,
		bool up);

		#endif /* CFCNFG_H_ */

net/caif/caif_dev.c

+159 −118

Original line number	Diff line number	Diff line
		@@ -12,14 +12,11 @@
		#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__

		#include <linux/version.h>
		#include <linux/module.h>
		#include <linux/kernel.h>
		#include <linux/if_arp.h>
		#include <linux/net.h>
		#include <linux/netdevice.h>
		#include <linux/skbuff.h>
		#include <linux/sched.h>
		#include <linux/wait.h>
		#include <linux/mutex.h>
		#include <net/netns/generic.h>
		#include <net/net_namespace.h>
		#include <net/pkt_sched.h>
		@@ -30,23 +27,19 @@
		#include <net/caif/cfcnfg.h>

		MODULE_LICENSE("GPL");
		#define TIMEOUT (HZ*5)

		/* Used for local tracking of the CAIF net devices */
		struct caif_device_entry {
		struct cflayer layer;
		struct list_head list;
		atomic_t in_use;
		atomic_t state;
		u16 phyid;
		struct net_device *netdev;
		wait_queue_head_t event;
		int __percpu *pcpu_refcnt;
		};

		struct caif_device_entry_list {
		struct list_head list;
		/* Protects simulanous deletes in list */
		spinlock_t lock;
		struct mutex lock;
		};

		struct caif_net {
		@@ -65,19 +58,39 @@ static struct caif_device_entry_list caif_device_list(struct net net)
		return &caifn->caifdevs;
		}

		static void caifd_put(struct caif_device_entry *e)
		{
		irqsafe_cpu_dec(*e->pcpu_refcnt);
		}

		static void caifd_hold(struct caif_device_entry *e)
		{
		irqsafe_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));
		BUG_ON(!caifdevs);

		caifd = kzalloc(sizeof(*caifd), GFP_ATOMIC);
		if (!caifd)
		return NULL;
		caifd->pcpu_refcnt = alloc_percpu(int);
		caifd->netdev = dev;
		list_add(&caifd->list, &caifdevs->list);
		init_waitqueue_head(&caifd->event);
		dev_hold(dev);
		return caifd;
		}

		@@ -87,35 +100,13 @@ static struct caif_device_entry caif_get(struct net_device dev)
		caif_device_list(dev_net(dev));
		struct caif_device_entry *caifd;
		BUG_ON(!caifdevs);
		list_for_each_entry(caifd, &caifdevs->list, list) {
		list_for_each_entry_rcu(caifd, &caifdevs->list, list) {
		if (caifd->netdev == dev)
		return caifd;
		}
		return NULL;
		}

		static void caif_device_destroy(struct net_device *dev)
		{
		struct caif_device_entry_list *caifdevs =
		caif_device_list(dev_net(dev));
		struct caif_device_entry *caifd;
		ASSERT_RTNL();
		if (dev->type != ARPHRD_CAIF)
		return;

		spin_lock_bh(&caifdevs->lock);
		caifd = caif_get(dev);
		if (caifd == NULL) {
		spin_unlock_bh(&caifdevs->lock);
		return;
		}

		list_del(&caifd->list);
		spin_unlock_bh(&caifdevs->lock);

		kfree(caifd);
		}

		static int transmit(struct cflayer layer, struct cfpkt pkt)
		{
		struct caif_device_entry *caifd =
		@@ -130,23 +121,8 @@ static int transmit(struct cflayer layer, struct cfpkt pkt)
		return 0;
		}

		static int modemcmd(struct cflayer *layr, enum caif_modemcmd ctrl)
		{
		struct caif_device_entry *caifd;
		caifd = container_of(layr, struct caif_device_entry, layer);
		if (ctrl == _CAIF_MODEMCMD_PHYIF_USEFULL) {
		atomic_set(&caifd->in_use, 1);
		wake_up_interruptible(&caifd->event);

		} else if (ctrl == _CAIF_MODEMCMD_PHYIF_USELESS) {
		atomic_set(&caifd->in_use, 0);
		wake_up_interruptible(&caifd->event);
		}
		return 0;
		}

		/*
		* Stuff received packets to associated sockets.
		* 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,
		@@ -154,14 +130,27 @@ static int receive(struct sk_buff skb, struct net_device dev,
		{
		struct cfpkt *pkt;
		struct caif_device_entry *caifd;

		pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);

		rcu_read_lock();
		caifd = caif_get(dev);
		if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->receive)
		return NET_RX_DROP;

		if (caifd->layer.up->receive(caifd->layer.up, pkt))
		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();

		caifd->layer.up->receive(caifd->layer.up, pkt);

		/* Release reference to stack upwards */
		caifd_put(caifd);
		return 0;
		}

		@@ -172,15 +161,25 @@ static struct packet_type caif_packet_type __read_mostly = {

		static void dev_flowctrl(struct net_device *dev, int on)
		{
		struct caif_device_entry *caifd = caif_get(dev);
		if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->ctrlcmd)
		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);
		}

		/* notify Caif of device events */
		@@ -192,34 +191,22 @@ static int caif_device_notify(struct notifier_block *me, unsigned long what,
		struct caif_dev_common *caifdev;
		enum cfcnfg_phy_preference pref;
		enum cfcnfg_phy_type phy_type;
		struct caif_device_entry_list *caifdevs =
		caif_device_list(dev_net(dev));

		if (dev->type != ARPHRD_CAIF)
		return 0;

		switch (what) {
		case NETDEV_REGISTER:
		netdev_info(dev, "register\n");
		caifd = caif_device_alloc(dev);
		if (caifd == NULL)
		break;
		if (!caifd)
		return 0;

		caifdev = netdev_priv(dev);
		caifdev->flowctrl = dev_flowctrl;
		atomic_set(&caifd->state, what);
		break;

		case NETDEV_UP:
		netdev_info(dev, "up\n");
		caifd = caif_get(dev);
		if (caifd == NULL)
		break;
		caifdev = netdev_priv(dev);
		if (atomic_read(&caifd->state) == NETDEV_UP) {
		netdev_info(dev, "already up\n");
		break;
		}
		atomic_set(&caifd->state, what);
		caifd->layer.transmit = transmit;
		caifd->layer.modemcmd = modemcmd;

		if (caifdev->use_frag)
		phy_type = CFPHYTYPE_FRAG;
		@@ -237,62 +224,95 @@ static int caif_device_notify(struct notifier_block *me, unsigned long what,
		pref = CFPHYPREF_HIGH_BW;
		break;
		}
		dev_hold(dev);
		strncpy(caifd->layer.name, dev->name,
		sizeof(caifd->layer.name) - 1);
		caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;

		mutex_lock(&caifdevs->lock);
		list_add_rcu(&caifd->list, &caifdevs->list);

		cfcnfg_add_phy_layer(cfg,
		phy_type,
		dev,
		&caifd->layer,
		&caifd->phyid,
		0,
		pref,
		caifdev->use_fcs,
		caifdev->use_stx);
		strncpy(caifd->layer.name, dev->name,
		sizeof(caifd->layer.name) - 1);
		caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
		mutex_unlock(&caifdevs->lock);
		break;

		case NETDEV_GOING_DOWN:
		case NETDEV_UP:
		rcu_read_lock();

		caifd = caif_get(dev);
		if (caifd == NULL)
		if (caifd == NULL) {
		rcu_read_unlock();
		break;
		netdev_info(dev, "going down\n");
		}

		cfcnfg_set_phy_state(cfg, &caifd->layer, true);
		rcu_read_unlock();

		if (atomic_read(&caifd->state) == NETDEV_GOING_DOWN \|\|
		atomic_read(&caifd->state) == NETDEV_DOWN)
		break;

		atomic_set(&caifd->state, what);
		if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->ctrlcmd)
		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);
		might_sleep();
		wait_event_interruptible_timeout(caifd->event,
		atomic_read(&caifd->in_use) == 0,
		TIMEOUT);
		caifd_put(caifd);
		break;

		case NETDEV_DOWN:
		case NETDEV_UNREGISTER:
		mutex_lock(&caifdevs->lock);

		caifd = caif_get(dev);
		if (caifd == NULL)
		break;
		netdev_info(dev, "down\n");
		if (atomic_read(&caifd->in_use))
		netdev_warn(dev,
		"Unregistering an active CAIF device\n");
		cfcnfg_del_phy_layer(cfg, &caifd->layer);
		dev_put(dev);
		atomic_set(&caifd->state, what);
		if (caifd == NULL) {
		mutex_unlock(&caifdevs->lock);
		break;
		}
		list_del_rcu(&caifd->list);

		case NETDEV_UNREGISTER:
		caifd = caif_get(dev);
		if (caifd == NULL)
		/*
		* 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;
		netdev_info(dev, "unregister\n");
		atomic_set(&caifd->state, what);
		caif_device_destroy(dev);
		}

		synchronize_rcu();
		dev_put(caifd->netdev);
		free_percpu(caifd->pcpu_refcnt);
		kfree(caifd);

		mutex_unlock(&caifdevs->lock);
		break;
		}
		return 0;
		@@ -331,20 +351,40 @@ static int caif_init_net(struct net *net)
		{
		struct caif_net *caifn = net_generic(net, caif_net_id);
		INIT_LIST_HEAD(&caifn->caifdevs.list);
		spin_lock_init(&caifn->caifdevs.lock);
		mutex_init(&caifn->caifdevs.lock);
		return 0;
		}

		static void caif_exit_net(struct net *net)
		{
		struct net_device *dev;
		struct caif_device_entry caifd, tmp;
		struct caif_device_entry_list *caifdevs =
		caif_device_list(net);

		rtnl_lock();
		for_each_netdev(net, dev) {
		if (dev->type != ARPHRD_CAIF)
		continue;
		dev_close(dev);
		caif_device_destroy(dev);
		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);
		}


		mutex_unlock(&caifdevs->lock);
		rtnl_unlock();
		}

		@@ -359,6 +399,7 @@ static struct pernet_operations caif_net_ops = {
		static int __init caif_device_init(void)
		{
		int result;

		cfg = cfcnfg_create();
		if (!cfg) {
		pr_warn("can't create cfcnfg\n");

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