[PATCH net-next-2.6] igmp: RCU conversion of in_dev->mc_list

From: Eric Dumazet
Date: Fri Nov 12 2010 - 08:34:30 EST

Le vendredi 12 novembre 2010 Ã 10:22 +0100, Eric Dumazet a Ãcrit :
> Le vendredi 12 novembre 2010 Ã 16:19 +0800, AmÃrico Wang a Ãcrit :
> > On Fri, Nov 12, 2010 at 08:27:54AM +0100, Eric Dumazet wrote:
>
> > >A RCU conversion is far more complex.
> > >
> >
> > Yup.
>
>
> Well, actually this is easy in this case.
>
> I'll post a patch to do this RCU conversion.
>
>

Note : compile tested only, I'll appreciate if someone can test it ;)

Note: one patch from net-2.6 is not yet included in net-next-2.6, so
please make sure you have it before testing ;)

( http://git.kernel.org/?p=linux/kernel/git/davem/net-2.6.git;a=commitdiff;h=18943d292facbc70e6a36fc62399ae833f64671b )


Thanks

[PATCH net-next-2.6] 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: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Cc: Cypher Wu <cypher.w@xxxxxxxxx>
Cc: AmÃrico Wang <xiyou.wangcong@xxxxxxxxx>
---
include/linux/igmp.h | 12 +
include/linux/inetdevice.h | 5
include/net/inet_sock.h | 2
net/ipv4/igmp.c | 223 ++++++++++++++++-------------------
4 files changed, 115 insertions(+), 127 deletions(-)

diff --git a/include/linux/igmp.h b/include/linux/igmp.h
index 93fc244..7d16467 100644
--- a/include/linux/igmp.h
+++ b/include/linux/igmp.h
@@ -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 */
diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index ccd5b07..380ba6b 100644
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -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;
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 1989cfd..8945f9f 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -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;
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 08d0d81..ff4e5fd 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -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;
- }
+
+ 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->idev = NULL;
state->dev = NULL;
rcu_read_unlock();
}


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