igmp: hash a hash table to speedup ip_check_mc_rcu() (e9897071) · Commits · 戴 / test

include/linux/igmp.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -84,6 +84,7 @@ struct ip_mc_list {
		struct ip_mc_list *next;
		struct ip_mc_list __rcu *next_rcu;
		};
		struct ip_mc_list __rcu *next_hash;
		struct timer_list timer;
		int users;
		atomic_t refcnt;

include/linux/inetdevice.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -50,12 +50,17 @@ struct ipv4_devconf {
		DECLARE_BITMAP(state, IPV4_DEVCONF_MAX);
		};

		#define MC_HASH_SZ_LOG 9

		struct in_device {
		struct net_device *dev;
		atomic_t refcnt;
		int dead;
		struct in_ifaddr ifa_list; / IP ifaddr chain */

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

		int mc_count; /* Number of installed mcasts */
		spinlock_t mc_tomb_lock;
		struct ip_mc_list *mc_tomb;

net/ipv4/devinet.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -215,6 +215,7 @@ void in_dev_finish_destroy(struct in_device *idev)

		WARN_ON(idev->ifa_list);
		WARN_ON(idev->mc_list);
		kfree(rcu_dereference_protected(idev->mc_hash, 1));
		#ifdef NET_REFCNT_DEBUG
		pr_debug("%s: %p=%s\n", __func__, idev, dev ? dev->name : "NIL");
		#endif

net/ipv4/igmp.c

+70 −3

Original line number	Diff line number	Diff line
		@@ -1217,6 +1217,57 @@ static void igmp_group_added(struct ip_mc_list *im)
		* Multicast list managers
		*/

		static u32 ip_mc_hash(const struct ip_mc_list *im)
		{
		return hash_32((u32)im->multiaddr, MC_HASH_SZ_LOG);
		}

		static void ip_mc_hash_add(struct in_device *in_dev,
		struct ip_mc_list *im)
		{
		struct ip_mc_list __rcu **mc_hash;
		u32 hash;

		mc_hash = rtnl_dereference(in_dev->mc_hash);
		if (mc_hash) {
		hash = ip_mc_hash(im);
		im->next_hash = rtnl_dereference(mc_hash[hash]);
		rcu_assign_pointer(mc_hash[hash], im);
		return;
		}

		/* do not use a hash table for small number of items */
		if (in_dev->mc_count < 4)
		return;

		mc_hash = kzalloc(sizeof(struct ip_mc_list *) << MC_HASH_SZ_LOG,
		GFP_KERNEL);
		if (!mc_hash)
		return;

		for_each_pmc_rtnl(in_dev, im) {
		hash = ip_mc_hash(im);
		im->next_hash = rtnl_dereference(mc_hash[hash]);
		RCU_INIT_POINTER(mc_hash[hash], im);
		}

		rcu_assign_pointer(in_dev->mc_hash, mc_hash);
		}

		static void ip_mc_hash_remove(struct in_device *in_dev,
		struct ip_mc_list *im)
		{
		struct ip_mc_list __rcu **mc_hash = rtnl_dereference(in_dev->mc_hash);
		struct ip_mc_list *aux;

		if (!mc_hash)
		return;
		mc_hash += ip_mc_hash(im);
		while ((aux = rtnl_dereference(*mc_hash)) != im)
		mc_hash = &aux->next_hash;
		*mc_hash = im->next_hash;
		}


		/*
		* A socket has joined a multicast group on device dev.
		@@ -1258,6 +1309,8 @@ void ip_mc_inc_group(struct in_device *in_dev, __be32 addr)
		in_dev->mc_count++;
		rcu_assign_pointer(in_dev->mc_list, im);

		ip_mc_hash_add(in_dev, im);

		#ifdef CONFIG_IP_MULTICAST
		igmpv3_del_delrec(in_dev, im->multiaddr);
		#endif
		@@ -1314,6 +1367,7 @@ void ip_mc_dec_group(struct in_device *in_dev, __be32 addr)
		ip = &i->next_rcu) {
		if (i->multiaddr == addr) {
		if (--i->users == 0) {
		ip_mc_hash_remove(in_dev, i);
		*ip = i->next_rcu;
		in_dev->mc_count--;
		igmp_group_dropped(i);
		@@ -2321,13 +2375,26 @@ void ip_mc_drop_socket(struct sock *sk)
		int ip_check_mc_rcu(struct in_device *in_dev, __be32 mc_addr, __be32 src_addr, u16 proto)
		{
		struct ip_mc_list *im;
		struct ip_mc_list __rcu **mc_hash;
		struct ip_sf_list *psf;
		int rv = 0;

		mc_hash = rcu_dereference(in_dev->mc_hash);
		if (mc_hash) {
		u32 hash = hash_32((u32)mc_addr, MC_HASH_SZ_LOG);

		for (im = rcu_dereference(mc_hash[hash]);
		im != NULL;
		im = rcu_dereference(im->next_hash)) {
		if (im->multiaddr == mc_addr)
		break;
		}
		} else {
		for_each_pmc_rcu(in_dev, im) {
		if (im->multiaddr == mc_addr)
		break;
		}
		}
		if (im && proto == IPPROTO_IGMP) {
		rv = 1;
		} else if (im) {

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