Commit 8b448f0d authored by Paolo Abeni's avatar Paolo Abeni
Browse files

Merge branch 'phonet-convert-all-doit-and-dumpit-to-rcu' 

Kuniyuki Iwashima says:

====================
phonet: Convert all doit() and dumpit() to RCU.

addr_doit() and route_doit() access only phonet_device_list(dev_net(dev))
and phonet_pernet(dev_net(dev))->routes, respectively.

Each per-netns struct has its dedicated mutex, and RTNL also protects
the structs.  __dev_change_net_namespace() has synchronize_net(), so
we have two options to convert addr_doit() and route_doit().

  1. Use per-netns RTNL
  2. Use RCU and convert each struct mutex to spinlock_t

As RCU is preferable, this series converts all PF_PHONET's doit()
and dumpit() to RCU.

4 doit()s and 1 dumpit() are now converted to RCU, 70 doit()s and
28 dumpit()s are still under RTNL.
====================

Link: https://patch.msgid.link/20241017183140.43028-1-kuniyu@amazon.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parents 1bf70e6c 17a1ac00

include/net/phonet/pn_dev.h

+4 −4
Original line number Diff line number Diff line
@@ -11,13 +11,13 @@ 
#define PN_DEV_H



#include <linux/list.h>

#include <linux/mutex.h>

#include <linux/spinlock.h>



struct net;



struct phonet_device_list {

	struct list_head list;

	struct mutex lock;

	spinlock_t lock;

};



struct phonet_device_list *phonet_device_list(struct net *net);
@@ -38,11 +38,11 @@ int phonet_address_add(struct net_device *dev, u8 addr); 
int phonet_address_del(struct net_device *dev, u8 addr);

u8 phonet_address_get(struct net_device *dev, u8 addr);

int phonet_address_lookup(struct net *net, u8 addr);

void phonet_address_notify(int event, struct net_device *dev, u8 addr);

void phonet_address_notify(struct net *net, int event, u32 ifindex, u8 addr);



int phonet_route_add(struct net_device *dev, u8 daddr);

int phonet_route_del(struct net_device *dev, u8 daddr);

void rtm_phonet_notify(int event, struct net_device *dev, u8 dst);

void rtm_phonet_notify(struct net *net, int event, u32 ifindex, u8 dst);

struct net_device *phonet_route_get_rcu(struct net *net, u8 daddr);

struct net_device *phonet_route_output(struct net *net, u8 daddr);

net/phonet/pn_dev.c

+45 −24
Original line number Diff line number Diff line
@@ -22,7 +22,7 @@ 
#include <net/phonet/pn_dev.h>



struct phonet_routes {

	struct mutex		lock;

	spinlock_t		lock;

	struct net_device __rcu	*table[64];

};
@@ -54,7 +54,7 @@ static struct phonet_device *__phonet_device_alloc(struct net_device *dev) 
	pnd->netdev = dev;

	bitmap_zero(pnd->addrs, 64);



	BUG_ON(!mutex_is_locked(&pndevs->lock));

	lockdep_assert_held(&pndevs->lock);

	list_add_rcu(&pnd->list, &pndevs->list);

	return pnd;

}
@@ -64,7 +64,8 @@ static struct phonet_device *__phonet_get(struct net_device *dev) 
	struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));

	struct phonet_device *pnd;



	BUG_ON(!mutex_is_locked(&pndevs->lock));

	lockdep_assert_held(&pndevs->lock);



	list_for_each_entry(pnd, &pndevs->list, list) {

		if (pnd->netdev == dev)

			return pnd;
@@ -91,17 +92,22 @@ static void phonet_device_destroy(struct net_device *dev) 


	ASSERT_RTNL();



	mutex_lock(&pndevs->lock);

	spin_lock(&pndevs->lock);



	pnd = __phonet_get(dev);

	if (pnd)

		list_del_rcu(&pnd->list);

	mutex_unlock(&pndevs->lock);



	spin_unlock(&pndevs->lock);



	if (pnd) {

		struct net *net = dev_net(dev);

		u32 ifindex = dev->ifindex;

		u8 addr;



		for_each_set_bit(addr, pnd->addrs, 64)

			phonet_address_notify(RTM_DELADDR, dev, addr);

			phonet_address_notify(net, RTM_DELADDR, ifindex, addr);



		kfree(pnd);

	}

}
@@ -133,7 +139,8 @@ int phonet_address_add(struct net_device *dev, u8 addr) 
	struct phonet_device *pnd;

	int err = 0;



	mutex_lock(&pndevs->lock);

	spin_lock(&pndevs->lock);



	/* Find or create Phonet-specific device data */

	pnd = __phonet_get(dev);

	if (pnd == NULL)
@@ -142,7 +149,9 @@ int phonet_address_add(struct net_device *dev, u8 addr) 
		err = -ENOMEM;

	else if (test_and_set_bit(addr >> 2, pnd->addrs))

		err = -EEXIST;

	mutex_unlock(&pndevs->lock);



	spin_unlock(&pndevs->lock);



	return err;

}
@@ -152,7 +161,8 @@ int phonet_address_del(struct net_device *dev, u8 addr) 
	struct phonet_device *pnd;

	int err = 0;



	mutex_lock(&pndevs->lock);

	spin_lock(&pndevs->lock);



	pnd = __phonet_get(dev);

	if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {

		err = -EADDRNOTAVAIL;
@@ -161,7 +171,8 @@ int phonet_address_del(struct net_device *dev, u8 addr) 
		list_del_rcu(&pnd->list);

	else

		pnd = NULL;

	mutex_unlock(&pndevs->lock);



	spin_unlock(&pndevs->lock);



	if (pnd)

		kfree_rcu(pnd, rcu);
@@ -244,32 +255,39 @@ static int phonet_device_autoconf(struct net_device *dev) 
	ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);

	if (ret)

		return ret;

	phonet_address_notify(RTM_NEWADDR, dev,



	phonet_address_notify(dev_net(dev), RTM_NEWADDR, dev->ifindex,

			      req.ifr_phonet_autoconf.device);

	return 0;

}



static void phonet_route_autodel(struct net_device *dev)

{

	struct phonet_net *pnn = phonet_pernet(dev_net(dev));

	unsigned int i;

	struct net *net = dev_net(dev);

	DECLARE_BITMAP(deleted, 64);

	u32 ifindex = dev->ifindex;

	struct phonet_net *pnn;

	unsigned int i;



	pnn = phonet_pernet(net);



	/* Remove left-over Phonet routes */

	bitmap_zero(deleted, 64);

	mutex_lock(&pnn->routes.lock);

	for (i = 0; i < 64; i++)



	spin_lock(&pnn->routes.lock);

	for (i = 0; i < 64; i++) {

		if (rcu_access_pointer(pnn->routes.table[i]) == dev) {

			RCU_INIT_POINTER(pnn->routes.table[i], NULL);

			set_bit(i, deleted);

		}

	mutex_unlock(&pnn->routes.lock);

	}

	spin_unlock(&pnn->routes.lock);



	if (bitmap_empty(deleted, 64))

		return; /* short-circuit RCU */

	synchronize_rcu();

	for_each_set_bit(i, deleted, 64) {

		rtm_phonet_notify(RTM_DELROUTE, dev, i);

		rtm_phonet_notify(net, RTM_DELROUTE, ifindex, i);

		dev_put(dev);

	}

}
@@ -309,8 +327,8 @@ static int __net_init phonet_init_net(struct net *net) 
		return -ENOMEM;



	INIT_LIST_HEAD(&pnn->pndevs.list);

	mutex_init(&pnn->pndevs.lock);

	mutex_init(&pnn->routes.lock);

	spin_lock_init(&pnn->pndevs.lock);

	spin_lock_init(&pnn->routes.lock);

	return 0;

}
@@ -360,13 +378,15 @@ int phonet_route_add(struct net_device *dev, u8 daddr) 
	int err = -EEXIST;



	daddr = daddr >> 2;

	mutex_lock(&routes->lock);



	spin_lock(&routes->lock);

	if (routes->table[daddr] == NULL) {

		rcu_assign_pointer(routes->table[daddr], dev);

		dev_hold(dev);

		err = 0;

	}

	mutex_unlock(&routes->lock);

	spin_unlock(&routes->lock);



	return err;

}
@@ -376,12 +396,13 @@ int phonet_route_del(struct net_device *dev, u8 daddr) 
	struct phonet_routes *routes = &pnn->routes;



	daddr = daddr >> 2;

	mutex_lock(&routes->lock);



	spin_lock(&routes->lock);

	if (rcu_access_pointer(routes->table[daddr]) == dev)

		RCU_INIT_POINTER(routes->table[daddr], NULL);

	else

		dev = NULL;

	mutex_unlock(&routes->lock);

	spin_unlock(&routes->lock);



	if (!dev)

		return -ENOENT;

net/phonet/pn_netlink.c

+71 −44
Original line number Diff line number Diff line
@@ -19,10 +19,10 @@ 


/* Device address handling */



static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,

static int fill_addr(struct sk_buff *skb, u32 ifindex, u8 addr,

		     u32 portid, u32 seq, int event);



void phonet_address_notify(int event, struct net_device *dev, u8 addr)

void phonet_address_notify(struct net *net, int event, u32 ifindex, u8 addr)

{

	struct sk_buff *skb;

	int err = -ENOBUFS;
@@ -31,17 +31,18 @@ void phonet_address_notify(int event, struct net_device *dev, u8 addr) 
			nla_total_size(1), GFP_KERNEL);

	if (skb == NULL)

		goto errout;

	err = fill_addr(skb, dev, addr, 0, 0, event);



	err = fill_addr(skb, ifindex, addr, 0, 0, event);

	if (err < 0) {

		WARN_ON(err == -EMSGSIZE);

		kfree_skb(skb);

		goto errout;

	}

	rtnl_notify(skb, dev_net(dev), 0,

		    RTNLGRP_PHONET_IFADDR, NULL, GFP_KERNEL);



	rtnl_notify(skb, net, 0, RTNLGRP_PHONET_IFADDR, NULL, GFP_KERNEL);

	return;

errout:

	rtnl_set_sk_err(dev_net(dev), RTNLGRP_PHONET_IFADDR, err);

	rtnl_set_sk_err(net, RTNLGRP_PHONET_IFADDR, err);

}



static const struct nla_policy ifa_phonet_policy[IFA_MAX+1] = {
@@ -64,8 +65,6 @@ static int addr_doit(struct sk_buff *skb, struct nlmsghdr *nlh, 
	if (!netlink_capable(skb, CAP_SYS_ADMIN))

		return -EPERM;



	ASSERT_RTNL();



	err = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX,

				     ifa_phonet_policy, extack);

	if (err < 0)
@@ -79,20 +78,28 @@ static int addr_doit(struct sk_buff *skb, struct nlmsghdr *nlh, 
		/* Phonet addresses only have 6 high-order bits */

		return -EINVAL;



	dev = __dev_get_by_index(net, ifm->ifa_index);

	if (dev == NULL)

	rcu_read_lock();



	dev = dev_get_by_index_rcu(net, ifm->ifa_index);

	if (!dev) {

		rcu_read_unlock();

		return -ENODEV;

	}



	if (nlh->nlmsg_type == RTM_NEWADDR)

		err = phonet_address_add(dev, pnaddr);

	else

		err = phonet_address_del(dev, pnaddr);



	rcu_read_unlock();



	if (!err)

		phonet_address_notify(nlh->nlmsg_type, dev, pnaddr);

		phonet_address_notify(net, nlh->nlmsg_type, ifm->ifa_index, pnaddr);



	return err;

}



static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,

static int fill_addr(struct sk_buff *skb, u32 ifindex, u8 addr,

		     u32 portid, u32 seq, int event)

{

	struct ifaddrmsg *ifm;
@@ -107,7 +114,7 @@ static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr, 
	ifm->ifa_prefixlen = 0;

	ifm->ifa_flags = IFA_F_PERMANENT;

	ifm->ifa_scope = RT_SCOPE_LINK;

	ifm->ifa_index = dev->ifindex;

	ifm->ifa_index = ifindex;

	if (nla_put_u8(skb, IFA_LOCAL, addr))

		goto nla_put_failure;

	nlmsg_end(skb, nlh);
@@ -120,14 +127,17 @@ static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr, 


static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)

{

	int addr_idx = 0, addr_start_idx = cb->args[1];

	int dev_idx = 0, dev_start_idx = cb->args[0];

	struct phonet_device_list *pndevs;

	struct phonet_device *pnd;

	int dev_idx = 0, dev_start_idx = cb->args[0];

	int addr_idx = 0, addr_start_idx = cb->args[1];

	int err = 0;



	pndevs = phonet_device_list(sock_net(skb->sk));



	rcu_read_lock();

	list_for_each_entry_rcu(pnd, &pndevs->list, list) {

		DECLARE_BITMAP(addrs, 64);

		u8 addr;



		if (dev_idx > dev_start_idx)
@@ -136,28 +146,31 @@ static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 
			continue;



		addr_idx = 0;

		for_each_set_bit(addr, pnd->addrs, 64) {

		memcpy(addrs, pnd->addrs, sizeof(pnd->addrs));



		for_each_set_bit(addr, addrs, 64) {

			if (addr_idx++ < addr_start_idx)

				continue;



			if (fill_addr(skb, pnd->netdev, addr << 2,

					 NETLINK_CB(cb->skb).portid,

					cb->nlh->nlmsg_seq, RTM_NEWADDR) < 0)

			err = fill_addr(skb, READ_ONCE(pnd->netdev->ifindex),

					addr << 2, NETLINK_CB(cb->skb).portid,

					cb->nlh->nlmsg_seq, RTM_NEWADDR);

			if (err < 0)

				goto out;

		}

	}



out:

	rcu_read_unlock();



	cb->args[0] = dev_idx;

	cb->args[1] = addr_idx;



	return skb->len;

	return err;

}



/* Routes handling */



static int fill_route(struct sk_buff *skb, struct net_device *dev, u8 dst,

static int fill_route(struct sk_buff *skb, u32 ifindex, u8 dst,

		      u32 portid, u32 seq, int event)

{

	struct rtmsg *rtm;
@@ -177,8 +190,7 @@ static int fill_route(struct sk_buff *skb, struct net_device *dev, u8 dst, 
	rtm->rtm_scope = RT_SCOPE_UNIVERSE;

	rtm->rtm_type = RTN_UNICAST;

	rtm->rtm_flags = 0;

	if (nla_put_u8(skb, RTA_DST, dst) ||

	    nla_put_u32(skb, RTA_OIF, READ_ONCE(dev->ifindex)))

	if (nla_put_u8(skb, RTA_DST, dst) || nla_put_u32(skb, RTA_OIF, ifindex))

		goto nla_put_failure;

	nlmsg_end(skb, nlh);

	return 0;
@@ -188,7 +200,7 @@ static int fill_route(struct sk_buff *skb, struct net_device *dev, u8 dst, 
	return -EMSGSIZE;

}



void rtm_phonet_notify(int event, struct net_device *dev, u8 dst)

void rtm_phonet_notify(struct net *net, int event, u32 ifindex, u8 dst)

{

	struct sk_buff *skb;

	int err = -ENOBUFS;
@@ -197,17 +209,18 @@ void rtm_phonet_notify(int event, struct net_device *dev, u8 dst) 
			nla_total_size(1) + nla_total_size(4), GFP_KERNEL);

	if (skb == NULL)

		goto errout;

	err = fill_route(skb, dev, dst, 0, 0, event);



	err = fill_route(skb, ifindex, dst, 0, 0, event);

	if (err < 0) {

		WARN_ON(err == -EMSGSIZE);

		kfree_skb(skb);

		goto errout;

	}

	rtnl_notify(skb, dev_net(dev), 0,

			  RTNLGRP_PHONET_ROUTE, NULL, GFP_KERNEL);



	rtnl_notify(skb, net, 0, RTNLGRP_PHONET_ROUTE, NULL, GFP_KERNEL);

	return;

errout:

	rtnl_set_sk_err(dev_net(dev), RTNLGRP_PHONET_ROUTE, err);

	rtnl_set_sk_err(net, RTNLGRP_PHONET_ROUTE, err);

}



static const struct nla_policy rtm_phonet_policy[RTA_MAX+1] = {
@@ -222,6 +235,7 @@ static int route_doit(struct sk_buff *skb, struct nlmsghdr *nlh, 
	struct nlattr *tb[RTA_MAX+1];

	struct net_device *dev;

	struct rtmsg *rtm;

	u32 ifindex;

	int err;

	u8 dst;
@@ -231,8 +245,6 @@ static int route_doit(struct sk_buff *skb, struct nlmsghdr *nlh, 
	if (!netlink_capable(skb, CAP_SYS_ADMIN))

		return -EPERM;



	ASSERT_RTNL();



	err = nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,

				     rtm_phonet_policy, extack);

	if (err < 0)
@@ -247,16 +259,26 @@ static int route_doit(struct sk_buff *skb, struct nlmsghdr *nlh, 
	if (dst & 3) /* Phonet addresses only have 6 high-order bits */

		return -EINVAL;



	dev = __dev_get_by_index(net, nla_get_u32(tb[RTA_OIF]));

	if (dev == NULL)

	ifindex = nla_get_u32(tb[RTA_OIF]);



	rcu_read_lock();



	dev = dev_get_by_index_rcu(net, ifindex);

	if (!dev) {

		rcu_read_unlock();

		return -ENODEV;

	}



	if (nlh->nlmsg_type == RTM_NEWROUTE)

		err = phonet_route_add(dev, dst);

	else

		err = phonet_route_del(dev, dst);



	rcu_read_unlock();



	if (!err)

		rtm_phonet_notify(nlh->nlmsg_type, dev, dst);

		rtm_phonet_notify(net, nlh->nlmsg_type, ifindex, dst);



	return err;

}
@@ -273,7 +295,7 @@ static int route_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 
		if (!dev)

			continue;



		err = fill_route(skb, dev, addr << 2,

		err = fill_route(skb, READ_ONCE(dev->ifindex), addr << 2,

				 NETLINK_CB(cb->skb).portid,

				 cb->nlh->nlmsg_seq, RTM_NEWROUTE);

		if (err < 0)
@@ -286,13 +308,18 @@ static int route_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 
}



static const struct rtnl_msg_handler phonet_rtnl_msg_handlers[] __initdata_or_module = {

	{THIS_MODULE, PF_PHONET, RTM_NEWADDR, addr_doit, NULL, 0},

	{THIS_MODULE, PF_PHONET, RTM_DELADDR, addr_doit, NULL, 0},

	{THIS_MODULE, PF_PHONET, RTM_GETADDR, NULL, getaddr_dumpit, 0},

	{THIS_MODULE, PF_PHONET, RTM_NEWROUTE, route_doit, NULL, 0},

	{THIS_MODULE, PF_PHONET, RTM_DELROUTE, route_doit, NULL, 0},

	{THIS_MODULE, PF_PHONET, RTM_GETROUTE, NULL, route_dumpit,

	 RTNL_FLAG_DUMP_UNLOCKED},

	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_NEWADDR,

	 .doit = addr_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},

	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_DELADDR,

	 .doit = addr_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},

	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_GETADDR,

	 .dumpit = getaddr_dumpit, .flags = RTNL_FLAG_DUMP_UNLOCKED},

	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_NEWROUTE,

	 .doit = route_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},

	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_DELROUTE,

	 .doit = route_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},

	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_GETROUTE,

	 .dumpit = route_dumpit, .flags = RTNL_FLAG_DUMP_UNLOCKED},

};



int __init phonet_netlink_register(void)