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

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
......@@ -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];
struct ip_mc_list *next;
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 */
......
......@@ -52,9 +52,8 @@ 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 */
int mc_count; /* Number of installed mcasts */
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;
unsigned long mr_v1_seen;
......
......@@ -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;
......
......@@ -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 @@ empty_source:
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;