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Commit 91cc3bb0 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

xfrm6_tunnel: RCU conversion 



xfrm6_tunnels use one rwlock to protect their hash tables.

Plain and straightforward conversion to RCU locking to permit better SMP
performance.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4543c10d

net/ipv6/xfrm6_tunnel.c

+28 −19
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ 
 */

#include <linux/module.h>

#include <linux/xfrm.h>

#include <linux/list.h>

#include <linux/rculist.h>

#include <net/ip.h>

#include <net/xfrm.h>

#include <net/ipv6.h>
@@ -41,9 +41,10 @@ struct xfrm6_tunnel_spi { 
	xfrm_address_t		addr;

	u32			spi;

	atomic_t		refcnt;

	struct rcu_head		rcu_head;

};



static DEFINE_RWLOCK(xfrm6_tunnel_spi_lock);

static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);



static u32 xfrm6_tunnel_spi;
@@ -107,6 +108,7 @@ static void xfrm6_tunnel_spi_fini(void) 
		if (!hlist_empty(&xfrm6_tunnel_spi_byspi[i]))

			return;

	}

	rcu_barrier();

	kmem_cache_destroy(xfrm6_tunnel_spi_kmem);

	xfrm6_tunnel_spi_kmem = NULL;

}
@@ -116,7 +118,7 @@ static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr) 
	struct xfrm6_tunnel_spi *x6spi;

	struct hlist_node *pos;



	hlist_for_each_entry(x6spi, pos,

	hlist_for_each_entry_rcu(x6spi, pos,

			     &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],

			     list_byaddr) {

		if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0)
@@ -131,10 +133,10 @@ __be32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr) 
	struct xfrm6_tunnel_spi *x6spi;

	u32 spi;



	read_lock_bh(&xfrm6_tunnel_spi_lock);

	rcu_read_lock_bh();

	x6spi = __xfrm6_tunnel_spi_lookup(saddr);

	spi = x6spi ? x6spi->spi : 0;

	read_unlock_bh(&xfrm6_tunnel_spi_lock);

	rcu_read_unlock_bh();

	return htonl(spi);

}
@@ -185,14 +187,15 @@ static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr) 
	if (!x6spi)

		goto out;



	INIT_RCU_HEAD(&x6spi->rcu_head);

	memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));

	x6spi->spi = spi;

	atomic_set(&x6spi->refcnt, 1);



	hlist_add_head(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);

	hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);



	index = xfrm6_tunnel_spi_hash_byaddr(saddr);

	hlist_add_head(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);

	hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);

out:

	return spi;

}
@@ -202,26 +205,32 @@ __be32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr) 
	struct xfrm6_tunnel_spi *x6spi;

	u32 spi;



	write_lock_bh(&xfrm6_tunnel_spi_lock);

	spin_lock_bh(&xfrm6_tunnel_spi_lock);

	x6spi = __xfrm6_tunnel_spi_lookup(saddr);

	if (x6spi) {

		atomic_inc(&x6spi->refcnt);

		spi = x6spi->spi;

	} else

		spi = __xfrm6_tunnel_alloc_spi(saddr);

	write_unlock_bh(&xfrm6_tunnel_spi_lock);

	spin_unlock_bh(&xfrm6_tunnel_spi_lock);



	return htonl(spi);

}



EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);



static void x6spi_destroy_rcu(struct rcu_head *head)

{

	kmem_cache_free(xfrm6_tunnel_spi_kmem,

			container_of(head, struct xfrm6_tunnel_spi, rcu_head));

}



void xfrm6_tunnel_free_spi(xfrm_address_t *saddr)

{

	struct xfrm6_tunnel_spi *x6spi;

	struct hlist_node *pos, *n;



	write_lock_bh(&xfrm6_tunnel_spi_lock);

	spin_lock_bh(&xfrm6_tunnel_spi_lock);



	hlist_for_each_entry_safe(x6spi, pos, n,

				  &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
@@ -229,14 +238,14 @@ void xfrm6_tunnel_free_spi(xfrm_address_t *saddr) 
	{

		if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {

			if (atomic_dec_and_test(&x6spi->refcnt)) {

				hlist_del(&x6spi->list_byaddr);

				hlist_del(&x6spi->list_byspi);

				kmem_cache_free(xfrm6_tunnel_spi_kmem, x6spi);

				hlist_del_rcu(&x6spi->list_byaddr);

				hlist_del_rcu(&x6spi->list_byspi);

				call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);

				break;

			}

		}

	}

	write_unlock_bh(&xfrm6_tunnel_spi_lock);

	spin_unlock_bh(&xfrm6_tunnel_spi_lock);

}



EXPORT_SYMBOL(xfrm6_tunnel_free_spi);