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Commit 456b61bc authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipv6: mcast: RCU conversion 



ipv6_sk_mc_lock rwlock becomes a spinlock.

readers (inet6_mc_check()) now takes rcu_read_lock() instead of read
lock. Writers dont need to disable BH anymore.

struct ipv6_mc_socklist objects are reclaimed after one RCU grace
period.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2757a15f

include/linux/ipv6.h

+1 −1
Original line number Diff line number Diff line
@@ -364,7 +364,7 @@ struct ipv6_pinfo { 


	__u32			dst_cookie;



	struct ipv6_mc_socklist	*ipv6_mc_list;

	struct ipv6_mc_socklist	__rcu *ipv6_mc_list;

	struct ipv6_ac_socklist	*ipv6_ac_list;

	struct ipv6_fl_socklist *ipv6_fl_list;

include/net/if_inet6.h

+2 −1
Original line number Diff line number Diff line
@@ -89,10 +89,11 @@ struct ip6_sf_socklist { 
struct ipv6_mc_socklist {

	struct in6_addr		addr;

	int			ifindex;

	struct ipv6_mc_socklist *next;

	struct ipv6_mc_socklist __rcu *next;

	rwlock_t		sflock;

	unsigned int		sfmode;		/* MCAST_{INCLUDE,EXCLUDE} */

	struct ip6_sf_socklist	*sflist;

	struct rcu_head		rcu;

};



struct ip6_sf_list {

net/ipv6/mcast.c

+44 −31
Original line number Diff line number Diff line
@@ -82,7 +82,7 @@ static void *__mld2_query_bugs[] __attribute__((__unused__)) = { 
static struct in6_addr mld2_all_mcr = MLD2_ALL_MCR_INIT;



/* Big mc list lock for all the sockets */

static DEFINE_RWLOCK(ipv6_sk_mc_lock);

static DEFINE_SPINLOCK(ipv6_sk_mc_lock);



static void igmp6_join_group(struct ifmcaddr6 *ma);

static void igmp6_leave_group(struct ifmcaddr6 *ma);
@@ -123,6 +123,11 @@ int sysctl_mld_max_msf __read_mostly = IPV6_MLD_MAX_MSF; 
 *	socket join on multicast group

 */



#define for_each_pmc_rcu(np, pmc)				\

	for (pmc = rcu_dereference(np->ipv6_mc_list);		\

	     pmc != NULL;					\

	     pmc = rcu_dereference(pmc->next))



int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)

{

	struct net_device *dev = NULL;
@@ -134,15 +139,15 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr) 
	if (!ipv6_addr_is_multicast(addr))

		return -EINVAL;



	read_lock_bh(&ipv6_sk_mc_lock);

	for (mc_lst=np->ipv6_mc_list; mc_lst; mc_lst=mc_lst->next) {

	rcu_read_lock();

	for_each_pmc_rcu(np, mc_lst) {

		if ((ifindex == 0 || mc_lst->ifindex == ifindex) &&

		    ipv6_addr_equal(&mc_lst->addr, addr)) {

			read_unlock_bh(&ipv6_sk_mc_lock);

			rcu_read_unlock();

			return -EADDRINUSE;

		}

	}

	read_unlock_bh(&ipv6_sk_mc_lock);

	rcu_read_unlock();



	mc_lst = sock_kmalloc(sk, sizeof(struct ipv6_mc_socklist), GFP_KERNEL);
@@ -186,33 +191,41 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr) 
		return err;

	}



	write_lock_bh(&ipv6_sk_mc_lock);

	spin_lock(&ipv6_sk_mc_lock);

	mc_lst->next = np->ipv6_mc_list;

	np->ipv6_mc_list = mc_lst;

	write_unlock_bh(&ipv6_sk_mc_lock);

	rcu_assign_pointer(np->ipv6_mc_list, mc_lst);

	spin_unlock(&ipv6_sk_mc_lock);



	rcu_read_unlock();



	return 0;

}



static void ipv6_mc_socklist_reclaim(struct rcu_head *head)

{

	kfree(container_of(head, struct ipv6_mc_socklist, rcu));

}

/*

 *	socket leave on multicast group

 */

int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)

{

	struct ipv6_pinfo *np = inet6_sk(sk);

	struct ipv6_mc_socklist *mc_lst, **lnk;

	struct ipv6_mc_socklist *mc_lst;

	struct ipv6_mc_socklist __rcu **lnk;

	struct net *net = sock_net(sk);



	write_lock_bh(&ipv6_sk_mc_lock);

	for (lnk = &np->ipv6_mc_list; (mc_lst = *lnk) !=NULL ; lnk = &mc_lst->next) {

	spin_lock(&ipv6_sk_mc_lock);

	for (lnk = &np->ipv6_mc_list;

	     (mc_lst = rcu_dereference_protected(*lnk,

			lockdep_is_held(&ipv6_sk_mc_lock))) !=NULL ;

	      lnk = &mc_lst->next) {

		if ((ifindex == 0 || mc_lst->ifindex == ifindex) &&

		    ipv6_addr_equal(&mc_lst->addr, addr)) {

			struct net_device *dev;



			*lnk = mc_lst->next;

			write_unlock_bh(&ipv6_sk_mc_lock);

			spin_unlock(&ipv6_sk_mc_lock);



			rcu_read_lock();

			dev = dev_get_by_index_rcu(net, mc_lst->ifindex);
@@ -225,11 +238,12 @@ int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr) 
			} else

				(void) ip6_mc_leave_src(sk, mc_lst, NULL);

			rcu_read_unlock();

			sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));

			atomic_sub(sizeof(*mc_lst), &sk->sk_omem_alloc);

			call_rcu(&mc_lst->rcu, ipv6_mc_socklist_reclaim);

			return 0;

		}

	}

	write_unlock_bh(&ipv6_sk_mc_lock);

	spin_unlock(&ipv6_sk_mc_lock);



	return -EADDRNOTAVAIL;

}
@@ -272,12 +286,13 @@ void ipv6_sock_mc_close(struct sock *sk) 
	struct ipv6_mc_socklist *mc_lst;

	struct net *net = sock_net(sk);



	write_lock_bh(&ipv6_sk_mc_lock);

	while ((mc_lst = np->ipv6_mc_list) != NULL) {

	spin_lock(&ipv6_sk_mc_lock);

	while ((mc_lst = rcu_dereference_protected(np->ipv6_mc_list,

				lockdep_is_held(&ipv6_sk_mc_lock))) != NULL) {

		struct net_device *dev;



		np->ipv6_mc_list = mc_lst->next;

		write_unlock_bh(&ipv6_sk_mc_lock);

		spin_unlock(&ipv6_sk_mc_lock);



		rcu_read_lock();

		dev = dev_get_by_index_rcu(net, mc_lst->ifindex);
@@ -290,11 +305,13 @@ void ipv6_sock_mc_close(struct sock *sk) 
		} else

			(void) ip6_mc_leave_src(sk, mc_lst, NULL);

		rcu_read_unlock();

		sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));



		write_lock_bh(&ipv6_sk_mc_lock);

		atomic_sub(sizeof(*mc_lst), &sk->sk_omem_alloc);

		call_rcu(&mc_lst->rcu, ipv6_mc_socklist_reclaim);



		spin_lock(&ipv6_sk_mc_lock);

	}

	write_unlock_bh(&ipv6_sk_mc_lock);

	spin_unlock(&ipv6_sk_mc_lock);

}



int ip6_mc_source(int add, int omode, struct sock *sk,
@@ -328,8 +345,7 @@ int ip6_mc_source(int add, int omode, struct sock *sk, 


	err = -EADDRNOTAVAIL;



	read_lock(&ipv6_sk_mc_lock);

	for (pmc=inet6->ipv6_mc_list; pmc; pmc=pmc->next) {

	for_each_pmc_rcu(inet6, pmc) {

		if (pgsr->gsr_interface && pmc->ifindex != pgsr->gsr_interface)

			continue;

		if (ipv6_addr_equal(&pmc->addr, group))
@@ -428,7 +444,6 @@ int ip6_mc_source(int add, int omode, struct sock *sk, 
done:

	if (pmclocked)

		write_unlock(&pmc->sflock);

	read_unlock(&ipv6_sk_mc_lock);

	read_unlock_bh(&idev->lock);

	rcu_read_unlock();

	if (leavegroup)
@@ -466,14 +481,13 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf) 
	dev = idev->dev;



	err = 0;

	read_lock(&ipv6_sk_mc_lock);



	if (gsf->gf_fmode == MCAST_INCLUDE && gsf->gf_numsrc == 0) {

		leavegroup = 1;

		goto done;

	}



	for (pmc=inet6->ipv6_mc_list; pmc; pmc=pmc->next) {

	for_each_pmc_rcu(inet6, pmc) {

		if (pmc->ifindex != gsf->gf_interface)

			continue;

		if (ipv6_addr_equal(&pmc->addr, group))
@@ -521,7 +535,6 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf) 
	write_unlock(&pmc->sflock);

	err = 0;

done:

	read_unlock(&ipv6_sk_mc_lock);

	read_unlock_bh(&idev->lock);

	rcu_read_unlock();

	if (leavegroup)
@@ -562,7 +575,7 @@ int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf, 
	 * so reading the list is safe.

	 */



	for (pmc=inet6->ipv6_mc_list; pmc; pmc=pmc->next) {

	for_each_pmc_rcu(inet6, pmc) {

		if (pmc->ifindex != gsf->gf_interface)

			continue;

		if (ipv6_addr_equal(group, &pmc->addr))
@@ -612,13 +625,13 @@ int inet6_mc_check(struct sock *sk, const struct in6_addr *mc_addr, 
	struct ip6_sf_socklist *psl;

	int rv = 1;



	read_lock(&ipv6_sk_mc_lock);

	for (mc = np->ipv6_mc_list; mc; mc = mc->next) {

	rcu_read_lock();

	for_each_pmc_rcu(np, mc) {

		if (ipv6_addr_equal(&mc->addr, mc_addr))

			break;

	}

	if (!mc) {

		read_unlock(&ipv6_sk_mc_lock);

		rcu_read_unlock();

		return 1;

	}

	read_lock(&mc->sflock);
@@ -638,7 +651,7 @@ int inet6_mc_check(struct sock *sk, const struct in6_addr *mc_addr, 
			rv = 0;

	}

	read_unlock(&mc->sflock);

	read_unlock(&ipv6_sk_mc_lock);

	rcu_read_unlock();



	return rv;

}