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Commit 1d7138de authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

igmp: RCU conversion of in_dev->mc_list 



in_dev->mc_list is protected by one rwlock (in_dev->mc_list_lock).

This can easily be converted to a RCU protection.

Writers hold RTNL, so mc_list_lock is removed, not replaced by a
spinlock.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Cc: Cypher Wu <cypher.w@gmail.com>
Cc: Américo Wang <xiyou.wangcong@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f5539b5b

include/linux/igmp.h

+8 −4
Original line number Diff line number Diff line
@@ -167,10 +167,10 @@ struct ip_sf_socklist { 
 */



struct ip_mc_socklist {

	struct ip_mc_socklist	*next;

	struct ip_mc_socklist __rcu *next_rcu;

	struct ip_mreqn		multi;

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

	struct ip_sf_socklist	*sflist;

	struct ip_sf_socklist __rcu	*sflist;

	struct rcu_head		rcu;

};
@@ -186,11 +186,14 @@ struct ip_sf_list { 
struct ip_mc_list {

	struct in_device	*interface;

	__be32			multiaddr;

	unsigned int		sfmode;

	struct ip_sf_list	*sources;

	struct ip_sf_list	*tomb;

	unsigned int		sfmode;

	unsigned long		sfcount[2];

	union {

		struct ip_mc_list *next;

		struct ip_mc_list __rcu *next_rcu;

	};

	struct timer_list	timer;

	int			users;

	atomic_t		refcnt;
@@ -201,6 +204,7 @@ struct ip_mc_list { 
	char			loaded;

	unsigned char		gsquery;	/* check source marks? */

	unsigned char		crcount;

	struct rcu_head		rcu;

};



/* V3 exponential field decoding */

include/linux/inetdevice.h

+2 −3
Original line number Diff line number Diff line
@@ -52,8 +52,7 @@ struct in_device { 
	atomic_t		refcnt;

	int			dead;

	struct in_ifaddr	*ifa_list;	/* IP ifaddr chain		*/

	rwlock_t		mc_list_lock;

	struct ip_mc_list	*mc_list;	/* IP multicast filter chain    */

	struct ip_mc_list __rcu	*mc_list;	/* IP multicast filter chain    */

	int			mc_count;	/* Number of installed mcasts	*/

	spinlock_t		mc_tomb_lock;

	struct ip_mc_list	*mc_tomb;

include/net/inet_sock.h

+1 −1
Original line number Diff line number Diff line
@@ -141,7 +141,7 @@ struct inet_sock { 
				nodefrag:1;

	int			mc_index;

	__be32			mc_addr;

	struct ip_mc_socklist	*mc_list;

	struct ip_mc_socklist __rcu	*mc_list;

	struct {

		unsigned int		flags;

		unsigned int		fragsize;

net/ipv4/igmp.c

+104 −119
Original line number Diff line number Diff line
@@ -149,11 +149,17 @@ static void ip_mc_clear_src(struct ip_mc_list *pmc); 
static int ip_mc_add_src(struct in_device *in_dev, __be32 *pmca, int sfmode,

			 int sfcount, __be32 *psfsrc, int delta);





static void ip_mc_list_reclaim(struct rcu_head *head)

{

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

}



static void ip_ma_put(struct ip_mc_list *im)

{

	if (atomic_dec_and_test(&im->refcnt)) {

		in_dev_put(im->interface);

		kfree(im);

		call_rcu(&im->rcu, ip_mc_list_reclaim);

	}

}
@@ -163,7 +169,7 @@ static void ip_ma_put(struct ip_mc_list *im) 
 *	Timer management

 */



static __inline__ void igmp_stop_timer(struct ip_mc_list *im)

static void igmp_stop_timer(struct ip_mc_list *im)

{

	spin_lock_bh(&im->lock);

	if (del_timer(&im->timer))
@@ -496,14 +502,24 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc, 
	return skb;

}



#define for_each_pmc_rcu(in_dev, pmc)				\

	for (pmc = rcu_dereference(in_dev->mc_list);		\

	     pmc != NULL;					\

	     pmc = rcu_dereference(pmc->next_rcu))



#define for_each_pmc_rtnl(in_dev, pmc)				\

	for (pmc = rtnl_dereference(in_dev->mc_list);		\

	     pmc != NULL;					\

	     pmc = rtnl_dereference(pmc->next_rcu))



static int igmpv3_send_report(struct in_device *in_dev, struct ip_mc_list *pmc)

{

	struct sk_buff *skb = NULL;

	int type;



	if (!pmc) {

		read_lock(&in_dev->mc_list_lock);

		for (pmc=in_dev->mc_list; pmc; pmc=pmc->next) {

		rcu_read_lock();

		for_each_pmc_rcu(in_dev, pmc) {

			if (pmc->multiaddr == IGMP_ALL_HOSTS)

				continue;

			spin_lock_bh(&pmc->lock);
@@ -514,7 +530,7 @@ static int igmpv3_send_report(struct in_device *in_dev, struct ip_mc_list *pmc) 
			skb = add_grec(skb, pmc, type, 0, 0);

			spin_unlock_bh(&pmc->lock);

		}

		read_unlock(&in_dev->mc_list_lock);

		rcu_read_unlock();

	} else {

		spin_lock_bh(&pmc->lock);

		if (pmc->sfcount[MCAST_EXCLUDE])
@@ -556,7 +572,7 @@ static void igmpv3_send_cr(struct in_device *in_dev) 
	struct sk_buff *skb = NULL;

	int type, dtype;



	read_lock(&in_dev->mc_list_lock);

	rcu_read_lock();

	spin_lock_bh(&in_dev->mc_tomb_lock);



	/* deleted MCA's */
@@ -593,7 +609,7 @@ static void igmpv3_send_cr(struct in_device *in_dev) 
	spin_unlock_bh(&in_dev->mc_tomb_lock);



	/* change recs */

	for (pmc=in_dev->mc_list; pmc; pmc=pmc->next) {

	for_each_pmc_rcu(in_dev, pmc) {

		spin_lock_bh(&pmc->lock);

		if (pmc->sfcount[MCAST_EXCLUDE]) {

			type = IGMPV3_BLOCK_OLD_SOURCES;
@@ -616,7 +632,7 @@ static void igmpv3_send_cr(struct in_device *in_dev) 
		}

		spin_unlock_bh(&pmc->lock);

	}

	read_unlock(&in_dev->mc_list_lock);

	rcu_read_unlock();



	if (!skb)

		return;
@@ -813,14 +829,14 @@ static void igmp_heard_report(struct in_device *in_dev, __be32 group) 
	if (group == IGMP_ALL_HOSTS)

		return;



	read_lock(&in_dev->mc_list_lock);

	for (im=in_dev->mc_list; im!=NULL; im=im->next) {

	rcu_read_lock();

	for_each_pmc_rcu(in_dev, im) {

		if (im->multiaddr == group) {

			igmp_stop_timer(im);

			break;

		}

	}

	read_unlock(&in_dev->mc_list_lock);

	rcu_read_unlock();

}



static void igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb,
@@ -906,8 +922,8 @@ static void igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb, 
	 * - Use the igmp->igmp_code field as the maximum

	 *   delay possible

	 */

	read_lock(&in_dev->mc_list_lock);

	for (im=in_dev->mc_list; im!=NULL; im=im->next) {

	rcu_read_lock();

	for_each_pmc_rcu(in_dev, im) {

		int changed;



		if (group && group != im->multiaddr)
@@ -925,7 +941,7 @@ static void igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb, 
		if (changed)

			igmp_mod_timer(im, max_delay);

	}

	read_unlock(&in_dev->mc_list_lock);

	rcu_read_unlock();

}



/* called in rcu_read_lock() section */
@@ -1110,8 +1126,8 @@ static void igmpv3_clear_delrec(struct in_device *in_dev) 
		kfree(pmc);

	}

	/* clear dead sources, too */

	read_lock(&in_dev->mc_list_lock);

	for (pmc=in_dev->mc_list; pmc; pmc=pmc->next) {

	rcu_read_lock();

	for_each_pmc_rcu(in_dev, pmc) {

		struct ip_sf_list *psf, *psf_next;



		spin_lock_bh(&pmc->lock);
@@ -1123,7 +1139,7 @@ static void igmpv3_clear_delrec(struct in_device *in_dev) 
			kfree(psf);

		}

	}

	read_unlock(&in_dev->mc_list_lock);

	rcu_read_unlock();

}

#endif
@@ -1209,7 +1225,7 @@ void ip_mc_inc_group(struct in_device *in_dev, __be32 addr) 


	ASSERT_RTNL();



	for (im=in_dev->mc_list; im; im=im->next) {

	for_each_pmc_rtnl(in_dev, im) {

		if (im->multiaddr == addr) {

			im->users++;

			ip_mc_add_src(in_dev, &addr, MCAST_EXCLUDE, 0, NULL, 0);
@@ -1217,7 +1233,7 @@ void ip_mc_inc_group(struct in_device *in_dev, __be32 addr) 
		}

	}



	im = kmalloc(sizeof(*im), GFP_KERNEL);

	im = kzalloc(sizeof(*im), GFP_KERNEL);

	if (!im)

		goto out;
@@ -1227,26 +1243,18 @@ void ip_mc_inc_group(struct in_device *in_dev, __be32 addr) 
	im->multiaddr = addr;

	/* initial mode is (EX, empty) */

	im->sfmode = MCAST_EXCLUDE;

	im->sfcount[MCAST_INCLUDE] = 0;

	im->sfcount[MCAST_EXCLUDE] = 1;

	im->sources = NULL;

	im->tomb = NULL;

	im->crcount = 0;

	atomic_set(&im->refcnt, 1);

	spin_lock_init(&im->lock);

#ifdef CONFIG_IP_MULTICAST

	im->tm_running = 0;

	setup_timer(&im->timer, &igmp_timer_expire, (unsigned long)im);

	im->unsolicit_count = IGMP_Unsolicited_Report_Count;

	im->reporter = 0;

	im->gsquery = 0;

#endif

	im->loaded = 0;

	write_lock_bh(&in_dev->mc_list_lock);

	im->next = in_dev->mc_list;

	in_dev->mc_list = im;



	im->next_rcu = in_dev->mc_list;

	in_dev->mc_count++;

	write_unlock_bh(&in_dev->mc_list_lock);

	rcu_assign_pointer(in_dev->mc_list, im);



#ifdef CONFIG_IP_MULTICAST

	igmpv3_del_delrec(in_dev, im->multiaddr);

#endif
@@ -1287,17 +1295,18 @@ EXPORT_SYMBOL(ip_mc_rejoin_group); 


void ip_mc_dec_group(struct in_device *in_dev, __be32 addr)

{

	struct ip_mc_list *i, **ip;

	struct ip_mc_list *i;

	struct ip_mc_list __rcu **ip;



	ASSERT_RTNL();



	for (ip=&in_dev->mc_list; (i=*ip)!=NULL; ip=&i->next) {

	for (ip = &in_dev->mc_list;

	     (i = rtnl_dereference(*ip)) != NULL;

	     ip = &i->next_rcu) {

		if (i->multiaddr == addr) {

			if (--i->users == 0) {

				write_lock_bh(&in_dev->mc_list_lock);

				*ip = i->next;

				*ip = i->next_rcu;

				in_dev->mc_count--;

				write_unlock_bh(&in_dev->mc_list_lock);

				igmp_group_dropped(i);



				if (!in_dev->dead)
@@ -1316,34 +1325,34 @@ EXPORT_SYMBOL(ip_mc_dec_group); 


void ip_mc_unmap(struct in_device *in_dev)

{

	struct ip_mc_list *i;

	struct ip_mc_list *pmc;



	ASSERT_RTNL();



	for (i = in_dev->mc_list; i; i = i->next)

		igmp_group_dropped(i);

	for_each_pmc_rtnl(in_dev, pmc)

		igmp_group_dropped(pmc);

}



void ip_mc_remap(struct in_device *in_dev)

{

	struct ip_mc_list *i;

	struct ip_mc_list *pmc;



	ASSERT_RTNL();



	for (i = in_dev->mc_list; i; i = i->next)

		igmp_group_added(i);

	for_each_pmc_rtnl(in_dev, pmc)

		igmp_group_added(pmc);

}



/* Device going down */



void ip_mc_down(struct in_device *in_dev)

{

	struct ip_mc_list *i;

	struct ip_mc_list *pmc;



	ASSERT_RTNL();



	for (i=in_dev->mc_list; i; i=i->next)

		igmp_group_dropped(i);

	for_each_pmc_rtnl(in_dev, pmc)

		igmp_group_dropped(pmc);



#ifdef CONFIG_IP_MULTICAST

	in_dev->mr_ifc_count = 0;
@@ -1374,7 +1383,6 @@ void ip_mc_init_dev(struct in_device *in_dev) 
	in_dev->mr_qrv = IGMP_Unsolicited_Report_Count;

#endif



	rwlock_init(&in_dev->mc_list_lock);

	spin_lock_init(&in_dev->mc_tomb_lock);

}
@@ -1382,14 +1390,14 @@ void ip_mc_init_dev(struct in_device *in_dev) 


void ip_mc_up(struct in_device *in_dev)

{

	struct ip_mc_list *i;

	struct ip_mc_list *pmc;



	ASSERT_RTNL();



	ip_mc_inc_group(in_dev, IGMP_ALL_HOSTS);



	for (i=in_dev->mc_list; i; i=i->next)

		igmp_group_added(i);

	for_each_pmc_rtnl(in_dev, pmc)

		igmp_group_added(pmc);

}



/*
@@ -1405,17 +1413,13 @@ void ip_mc_destroy_dev(struct in_device *in_dev) 
	/* Deactivate timers */

	ip_mc_down(in_dev);



	write_lock_bh(&in_dev->mc_list_lock);

	while ((i = in_dev->mc_list) != NULL) {

		in_dev->mc_list = i->next;

	while ((i = rtnl_dereference(in_dev->mc_list)) != NULL) {

		in_dev->mc_list = i->next_rcu;

		in_dev->mc_count--;

		write_unlock_bh(&in_dev->mc_list_lock);



		igmp_group_dropped(i);

		ip_ma_put(i);



		write_lock_bh(&in_dev->mc_list_lock);

	}

	write_unlock_bh(&in_dev->mc_list_lock);

}



/* RTNL is locked */
@@ -1513,18 +1517,18 @@ static int ip_mc_del_src(struct in_device *in_dev, __be32 *pmca, int sfmode, 


	if (!in_dev)

		return -ENODEV;

	read_lock(&in_dev->mc_list_lock);

	for (pmc=in_dev->mc_list; pmc; pmc=pmc->next) {

	rcu_read_lock();

	for_each_pmc_rcu(in_dev, pmc) {

		if (*pmca == pmc->multiaddr)

			break;

	}

	if (!pmc) {

		/* MCA not found?? bug */

		read_unlock(&in_dev->mc_list_lock);

		rcu_read_unlock();

		return -ESRCH;

	}

	spin_lock_bh(&pmc->lock);

	read_unlock(&in_dev->mc_list_lock);

	rcu_read_unlock();

#ifdef CONFIG_IP_MULTICAST

	sf_markstate(pmc);

#endif
@@ -1685,18 +1689,18 @@ static int ip_mc_add_src(struct in_device *in_dev, __be32 *pmca, int sfmode, 


	if (!in_dev)

		return -ENODEV;

	read_lock(&in_dev->mc_list_lock);

	for (pmc=in_dev->mc_list; pmc; pmc=pmc->next) {

	rcu_read_lock();

	for_each_pmc_rcu(in_dev, pmc) {

		if (*pmca == pmc->multiaddr)

			break;

	}

	if (!pmc) {

		/* MCA not found?? bug */

		read_unlock(&in_dev->mc_list_lock);

		rcu_read_unlock();

		return -ESRCH;

	}

	spin_lock_bh(&pmc->lock);

	read_unlock(&in_dev->mc_list_lock);

	rcu_read_unlock();



#ifdef CONFIG_IP_MULTICAST

	sf_markstate(pmc);
@@ -1793,7 +1797,7 @@ int ip_mc_join_group(struct sock *sk , struct ip_mreqn *imr) 


	err = -EADDRINUSE;

	ifindex = imr->imr_ifindex;

	for (i = inet->mc_list; i; i = i->next) {

	for_each_pmc_rtnl(inet, i) {

		if (i->multi.imr_multiaddr.s_addr == addr &&

		    i->multi.imr_ifindex == ifindex)

			goto done;
@@ -1807,7 +1811,7 @@ int ip_mc_join_group(struct sock *sk , struct ip_mreqn *imr) 
		goto done;



	memcpy(&iml->multi, imr, sizeof(*imr));

	iml->next = inet->mc_list;

	iml->next_rcu = inet->mc_list;

	iml->sflist = NULL;

	iml->sfmode = MCAST_EXCLUDE;

	rcu_assign_pointer(inet->mc_list, iml);
@@ -1821,17 +1825,14 @@ EXPORT_SYMBOL(ip_mc_join_group); 


static void ip_sf_socklist_reclaim(struct rcu_head *rp)

{

	struct ip_sf_socklist *psf;



	psf = container_of(rp, struct ip_sf_socklist, rcu);

	kfree(container_of(rp, struct ip_sf_socklist, rcu));

	/* sk_omem_alloc should have been decreased by the caller*/

	kfree(psf);

}



static int ip_mc_leave_src(struct sock *sk, struct ip_mc_socklist *iml,

			   struct in_device *in_dev)

{

	struct ip_sf_socklist *psf = iml->sflist;

	struct ip_sf_socklist *psf = rtnl_dereference(iml->sflist);

	int err;



	if (psf == NULL) {
@@ -1851,11 +1852,8 @@ static int ip_mc_leave_src(struct sock *sk, struct ip_mc_socklist *iml, 


static void ip_mc_socklist_reclaim(struct rcu_head *rp)

{

	struct ip_mc_socklist *iml;



	iml = container_of(rp, struct ip_mc_socklist, rcu);

	kfree(container_of(rp, struct ip_mc_socklist, rcu));

	/* sk_omem_alloc should have been decreased by the caller*/

	kfree(iml);

}
@@ -1866,7 +1864,8 @@ static void ip_mc_socklist_reclaim(struct rcu_head *rp) 
int ip_mc_leave_group(struct sock *sk, struct ip_mreqn *imr)

{

	struct inet_sock *inet = inet_sk(sk);

	struct ip_mc_socklist *iml, **imlp;

	struct ip_mc_socklist *iml;

	struct ip_mc_socklist __rcu **imlp;

	struct in_device *in_dev;

	struct net *net = sock_net(sk);

	__be32 group = imr->imr_multiaddr.s_addr;
@@ -1876,7 +1875,9 @@ int ip_mc_leave_group(struct sock *sk, struct ip_mreqn *imr) 
	rtnl_lock();

	in_dev = ip_mc_find_dev(net, imr);

	ifindex = imr->imr_ifindex;

	for (imlp = &inet->mc_list; (iml = *imlp) != NULL; imlp = &iml->next) {

	for (imlp = &inet->mc_list;

	     (iml = rtnl_dereference(*imlp)) != NULL;

	     imlp = &iml->next_rcu) {

		if (iml->multi.imr_multiaddr.s_addr != group)

			continue;

		if (ifindex) {
@@ -1888,7 +1889,7 @@ int ip_mc_leave_group(struct sock *sk, struct ip_mreqn *imr) 


		(void) ip_mc_leave_src(sk, iml, in_dev);



		rcu_assign_pointer(*imlp, iml->next);

		*imlp = iml->next_rcu;



		if (in_dev)

			ip_mc_dec_group(in_dev, group);
@@ -1934,7 +1935,7 @@ int ip_mc_source(int add, int omode, struct sock *sk, struct 
	}

	err = -EADDRNOTAVAIL;



	for (pmc=inet->mc_list; pmc; pmc=pmc->next) {

	for_each_pmc_rtnl(inet, pmc) {

		if ((pmc->multi.imr_multiaddr.s_addr ==

		     imr.imr_multiaddr.s_addr) &&

		    (pmc->multi.imr_ifindex == imr.imr_ifindex))
@@ -1958,7 +1959,7 @@ int ip_mc_source(int add, int omode, struct sock *sk, struct 
		pmc->sfmode = omode;

	}



	psl = pmc->sflist;

	psl = rtnl_dereference(pmc->sflist);

	if (!add) {

		if (!psl)

			goto done;	/* err = -EADDRNOTAVAIL */
@@ -2077,7 +2078,7 @@ int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf, int ifindex) 
		goto done;

	}



	for (pmc=inet->mc_list; pmc; pmc=pmc->next) {

	for_each_pmc_rtnl(inet, pmc) {

		if (pmc->multi.imr_multiaddr.s_addr == msf->imsf_multiaddr &&

		    pmc->multi.imr_ifindex == imr.imr_ifindex)

			break;
@@ -2107,7 +2108,7 @@ int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf, int ifindex) 
		(void) ip_mc_add_src(in_dev, &msf->imsf_multiaddr,

				     msf->imsf_fmode, 0, NULL, 0);

	}

	psl = pmc->sflist;

	psl = rtnl_dereference(pmc->sflist);

	if (psl) {

		(void) ip_mc_del_src(in_dev, &msf->imsf_multiaddr, pmc->sfmode,

			psl->sl_count, psl->sl_addr, 0);
@@ -2155,7 +2156,7 @@ int ip_mc_msfget(struct sock *sk, struct ip_msfilter *msf, 
	}

	err = -EADDRNOTAVAIL;



	for (pmc=inet->mc_list; pmc; pmc=pmc->next) {

	for_each_pmc_rtnl(inet, pmc) {

		if (pmc->multi.imr_multiaddr.s_addr == msf->imsf_multiaddr &&

		    pmc->multi.imr_ifindex == imr.imr_ifindex)

			break;
@@ -2163,7 +2164,7 @@ int ip_mc_msfget(struct sock *sk, struct ip_msfilter *msf, 
	if (!pmc)		/* must have a prior join */

		goto done;

	msf->imsf_fmode = pmc->sfmode;

	psl = pmc->sflist;

	psl = rtnl_dereference(pmc->sflist);

	rtnl_unlock();

	if (!psl) {

		len = 0;
@@ -2208,7 +2209,7 @@ int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf, 


	err = -EADDRNOTAVAIL;



	for (pmc=inet->mc_list; pmc; pmc=pmc->next) {

	for_each_pmc_rtnl(inet, pmc) {

		if (pmc->multi.imr_multiaddr.s_addr == addr &&

		    pmc->multi.imr_ifindex == gsf->gf_interface)

			break;
@@ -2216,7 +2217,7 @@ int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf, 
	if (!pmc)		/* must have a prior join */

		goto done;

	gsf->gf_fmode = pmc->sfmode;

	psl = pmc->sflist;

	psl = rtnl_dereference(pmc->sflist);

	rtnl_unlock();

	count = psl ? psl->sl_count : 0;

	copycount = count < gsf->gf_numsrc ? count : gsf->gf_numsrc;
@@ -2257,7 +2258,7 @@ int ip_mc_sf_allow(struct sock *sk, __be32 loc_addr, __be32 rmt_addr, int dif) 
		goto out;



	rcu_read_lock();

	for (pmc=rcu_dereference(inet->mc_list); pmc; pmc=rcu_dereference(pmc->next)) {

	for_each_pmc_rcu(inet, pmc) {

		if (pmc->multi.imr_multiaddr.s_addr == loc_addr &&

		    pmc->multi.imr_ifindex == dif)

			break;
@@ -2265,7 +2266,7 @@ int ip_mc_sf_allow(struct sock *sk, __be32 loc_addr, __be32 rmt_addr, int dif) 
	ret = inet->mc_all;

	if (!pmc)

		goto unlock;

	psl = pmc->sflist;

	psl = rcu_dereference(pmc->sflist);

	ret = (pmc->sfmode == MCAST_EXCLUDE);

	if (!psl)

		goto unlock;
@@ -2300,10 +2301,10 @@ void ip_mc_drop_socket(struct sock *sk) 
		return;



	rtnl_lock();

	while ((iml = inet->mc_list) != NULL) {

	while ((iml = rtnl_dereference(inet->mc_list)) != NULL) {

		struct in_device *in_dev;

		rcu_assign_pointer(inet->mc_list, iml->next);



		inet->mc_list = iml->next_rcu;

		in_dev = inetdev_by_index(net, iml->multi.imr_ifindex);

		(void) ip_mc_leave_src(sk, iml, in_dev);

		if (in_dev != NULL) {
@@ -2323,8 +2324,8 @@ int ip_check_mc(struct in_device *in_dev, __be32 mc_addr, __be32 src_addr, u16 p 
	struct ip_sf_list *psf;

	int rv = 0;



	read_lock(&in_dev->mc_list_lock);

	for (im=in_dev->mc_list; im; im=im->next) {

	rcu_read_lock();

	for_each_pmc_rcu(in_dev, im) {

		if (im->multiaddr == mc_addr)

			break;

	}
@@ -2345,7 +2346,7 @@ int ip_check_mc(struct in_device *in_dev, __be32 mc_addr, __be32 src_addr, u16 p 
		} else

			rv = 1; /* unspecified source; tentatively allow */

	}

	read_unlock(&in_dev->mc_list_lock);

	rcu_read_unlock();

	return rv;

}
@@ -2371,13 +2372,11 @@ static inline struct ip_mc_list *igmp_mc_get_first(struct seq_file *seq) 
		in_dev = __in_dev_get_rcu(state->dev);

		if (!in_dev)

			continue;

		read_lock(&in_dev->mc_list_lock);

		im = in_dev->mc_list;

		im = rcu_dereference(in_dev->mc_list);

		if (im) {

			state->in_dev = in_dev;

			break;

		}

		read_unlock(&in_dev->mc_list_lock);

	}

	return im;

}
@@ -2385,11 +2384,9 @@ static inline struct ip_mc_list *igmp_mc_get_first(struct seq_file *seq) 
static struct ip_mc_list *igmp_mc_get_next(struct seq_file *seq, struct ip_mc_list *im)

{

	struct igmp_mc_iter_state *state = igmp_mc_seq_private(seq);

	im = im->next;

	while (!im) {

		if (likely(state->in_dev != NULL))

			read_unlock(&state->in_dev->mc_list_lock);



	im = rcu_dereference(im->next_rcu);

	while (!im) {

		state->dev = next_net_device_rcu(state->dev);

		if (!state->dev) {

			state->in_dev = NULL;
@@ -2398,8 +2395,7 @@ static struct ip_mc_list *igmp_mc_get_next(struct seq_file *seq, struct ip_mc_li 
		state->in_dev = __in_dev_get_rcu(state->dev);

		if (!state->in_dev)

			continue;

		read_lock(&state->in_dev->mc_list_lock);

		im = state->in_dev->mc_list;

		im = rcu_dereference(state->in_dev->mc_list);

	}

	return im;

}
@@ -2435,10 +2431,8 @@ static void igmp_mc_seq_stop(struct seq_file *seq, void *v) 
	__releases(rcu)

{

	struct igmp_mc_iter_state *state = igmp_mc_seq_private(seq);

	if (likely(state->in_dev != NULL)) {

		read_unlock(&state->in_dev->mc_list_lock);



	state->in_dev = NULL;

	}

	state->dev = NULL;

	rcu_read_unlock();

}
@@ -2460,7 +2454,7 @@ static int igmp_mc_seq_show(struct seq_file *seq, void *v) 
		querier = "NONE";

#endif



		if (state->in_dev->mc_list == im) {

		if (rcu_dereference(state->in_dev->mc_list) == im) {

			seq_printf(seq, "%d\t%-10s: %5d %7s\n",

				   state->dev->ifindex, state->dev->name, state->in_dev->mc_count, querier);

		}
@@ -2519,8 +2513,7 @@ static inline struct ip_sf_list *igmp_mcf_get_first(struct seq_file *seq) 
		idev = __in_dev_get_rcu(state->dev);

		if (unlikely(idev == NULL))

			continue;

		read_lock(&idev->mc_list_lock);

		im = idev->mc_list;

		im = rcu_dereference(idev->mc_list);

		if (likely(im != NULL)) {

			spin_lock_bh(&im->lock);

			psf = im->sources;
@@ -2531,7 +2524,6 @@ static inline struct ip_sf_list *igmp_mcf_get_first(struct seq_file *seq) 
			}

			spin_unlock_bh(&im->lock);

		}

		read_unlock(&idev->mc_list_lock);

	}

	return psf;

}
@@ -2545,9 +2537,6 @@ static struct ip_sf_list *igmp_mcf_get_next(struct seq_file *seq, struct ip_sf_l 
		spin_unlock_bh(&state->im->lock);

		state->im = state->im->next;

		while (!state->im) {

			if (likely(state->idev != NULL))

				read_unlock(&state->idev->mc_list_lock);



			state->dev = next_net_device_rcu(state->dev);

			if (!state->dev) {

				state->idev = NULL;
@@ -2556,8 +2545,7 @@ static struct ip_sf_list *igmp_mcf_get_next(struct seq_file *seq, struct ip_sf_l 
			state->idev = __in_dev_get_rcu(state->dev);

			if (!state->idev)

				continue;

			read_lock(&state->idev->mc_list_lock);

			state->im = state->idev->mc_list;

			state->im = rcu_dereference(state->idev->mc_list);

		}

		if (!state->im)

			break;
@@ -2603,10 +2591,7 @@ static void igmp_mcf_seq_stop(struct seq_file *seq, void *v) 
		spin_unlock_bh(&state->im->lock);

		state->im = NULL;

	}

	if (likely(state->idev != NULL)) {

		read_unlock(&state->idev->mc_list_lock);

	state->idev = NULL;

	}

	state->dev = NULL;

	rcu_read_unlock();

}