mirror of
https://github.com/torvalds/linux.git
synced 2025-11-04 10:40:15 +02:00
l2tp: Convert rwlock to RCU
Reader/write locks are discouraged because they are slower than spin locks. So this patch converts the rwlocks used in the per_net structs to rcu. Signed-off-by: James Chapman <jchapman@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
James Chapman
David S. Miller
parent
309795f4be
commit
e02d494d2c
1 changed files with 42 additions and 36 deletions
|
|
@ -21,6 +21,7 @@
|
|||
#include <linux/module.h>
|
||||
#include <linux/string.h>
|
||||
#include <linux/list.h>
|
||||
#include <linux/rculist.h>
|
||||
#include <linux/uaccess.h>
|
||||
|
||||
#include <linux/kernel.h>
|
||||
|
|
@ -105,9 +106,9 @@ static atomic_t l2tp_session_count;
|
|||
static unsigned int l2tp_net_id;
|
||||
struct l2tp_net {
|
||||
struct list_head l2tp_tunnel_list;
|
||||
rwlock_t l2tp_tunnel_list_lock;
|
||||
spinlock_t l2tp_tunnel_list_lock;
|
||||
struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2];
|
||||
rwlock_t l2tp_session_hlist_lock;
|
||||
spinlock_t l2tp_session_hlist_lock;
|
||||
};
|
||||
|
||||
static inline struct l2tp_net *l2tp_pernet(struct net *net)
|
||||
|
|
@ -139,14 +140,14 @@ static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id)
|
|||
struct l2tp_session *session;
|
||||
struct hlist_node *walk;
|
||||
|
||||
read_lock_bh(&pn->l2tp_session_hlist_lock);
|
||||
hlist_for_each_entry(session, walk, session_list, global_hlist) {
|
||||
rcu_read_lock_bh();
|
||||
hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) {
|
||||
if (session->session_id == session_id) {
|
||||
read_unlock_bh(&pn->l2tp_session_hlist_lock);
|
||||
rcu_read_unlock_bh();
|
||||
return session;
|
||||
}
|
||||
}
|
||||
read_unlock_bh(&pn->l2tp_session_hlist_lock);
|
||||
rcu_read_unlock_bh();
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
|
@ -225,17 +226,17 @@ struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname)
|
|||
struct hlist_node *walk;
|
||||
struct l2tp_session *session;
|
||||
|
||||
read_lock_bh(&pn->l2tp_session_hlist_lock);
|
||||
rcu_read_lock_bh();
|
||||
for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
|
||||
hlist_for_each_entry(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) {
|
||||
hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) {
|
||||
if (!strcmp(session->ifname, ifname)) {
|
||||
read_unlock_bh(&pn->l2tp_session_hlist_lock);
|
||||
rcu_read_unlock_bh();
|
||||
return session;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
read_unlock_bh(&pn->l2tp_session_hlist_lock);
|
||||
rcu_read_unlock_bh();
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
|
@ -248,14 +249,14 @@ struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id)
|
|||
struct l2tp_tunnel *tunnel;
|
||||
struct l2tp_net *pn = l2tp_pernet(net);
|
||||
|
||||
read_lock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
list_for_each_entry(tunnel, &pn->l2tp_tunnel_list, list) {
|
||||
rcu_read_lock_bh();
|
||||
list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
|
||||
if (tunnel->tunnel_id == tunnel_id) {
|
||||
read_unlock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
rcu_read_unlock_bh();
|
||||
return tunnel;
|
||||
}
|
||||
}
|
||||
read_unlock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
rcu_read_unlock_bh();
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
|
@ -267,15 +268,15 @@ struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth)
|
|||
struct l2tp_tunnel *tunnel;
|
||||
int count = 0;
|
||||
|
||||
read_lock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
list_for_each_entry(tunnel, &pn->l2tp_tunnel_list, list) {
|
||||
rcu_read_lock_bh();
|
||||
list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
|
||||
if (++count > nth) {
|
||||
read_unlock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
rcu_read_unlock_bh();
|
||||
return tunnel;
|
||||
}
|
||||
}
|
||||
|
||||
read_unlock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
rcu_read_unlock_bh();
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
|
@ -1167,9 +1168,10 @@ void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
|
|||
if (tunnel->version != L2TP_HDR_VER_2) {
|
||||
struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
|
||||
|
||||
write_lock_bh(&pn->l2tp_session_hlist_lock);
|
||||
hlist_del_init(&session->global_hlist);
|
||||
write_unlock_bh(&pn->l2tp_session_hlist_lock);
|
||||
spin_lock_bh(&pn->l2tp_session_hlist_lock);
|
||||
hlist_del_init_rcu(&session->global_hlist);
|
||||
spin_unlock_bh(&pn->l2tp_session_hlist_lock);
|
||||
synchronize_rcu();
|
||||
}
|
||||
|
||||
if (session->session_close != NULL)
|
||||
|
|
@ -1206,9 +1208,10 @@ void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
|
|||
"%s: free...\n", tunnel->name);
|
||||
|
||||
/* Remove from tunnel list */
|
||||
write_lock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
list_del_init(&tunnel->list);
|
||||
write_unlock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
spin_lock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
list_del_rcu(&tunnel->list);
|
||||
spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
synchronize_rcu();
|
||||
|
||||
atomic_dec(&l2tp_tunnel_count);
|
||||
kfree(tunnel);
|
||||
|
|
@ -1310,9 +1313,10 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
|
|||
|
||||
/* Add tunnel to our list */
|
||||
INIT_LIST_HEAD(&tunnel->list);
|
||||
write_lock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
list_add(&tunnel->list, &pn->l2tp_tunnel_list);
|
||||
write_unlock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
spin_lock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
|
||||
spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
|
||||
synchronize_rcu();
|
||||
atomic_inc(&l2tp_tunnel_count);
|
||||
|
||||
/* Bump the reference count. The tunnel context is deleted
|
||||
|
|
@ -1370,9 +1374,10 @@ void l2tp_session_free(struct l2tp_session *session)
|
|||
if (tunnel->version != L2TP_HDR_VER_2) {
|
||||
struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
|
||||
|
||||
write_lock_bh(&pn->l2tp_session_hlist_lock);
|
||||
hlist_del_init(&session->global_hlist);
|
||||
write_unlock_bh(&pn->l2tp_session_hlist_lock);
|
||||
spin_lock_bh(&pn->l2tp_session_hlist_lock);
|
||||
hlist_del_init_rcu(&session->global_hlist);
|
||||
spin_unlock_bh(&pn->l2tp_session_hlist_lock);
|
||||
synchronize_rcu();
|
||||
}
|
||||
|
||||
if (session->session_id != 0)
|
||||
|
|
@ -1494,10 +1499,11 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
|
|||
if (tunnel->version != L2TP_HDR_VER_2) {
|
||||
struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
|
||||
|
||||
write_lock_bh(&pn->l2tp_session_hlist_lock);
|
||||
hlist_add_head(&session->global_hlist,
|
||||
spin_lock_bh(&pn->l2tp_session_hlist_lock);
|
||||
hlist_add_head_rcu(&session->global_hlist,
|
||||
l2tp_session_id_hash_2(pn, session_id));
|
||||
write_unlock_bh(&pn->l2tp_session_hlist_lock);
|
||||
spin_unlock_bh(&pn->l2tp_session_hlist_lock);
|
||||
synchronize_rcu();
|
||||
}
|
||||
|
||||
/* Ignore management session in session count value */
|
||||
|
|
@ -1524,12 +1530,12 @@ static __net_init int l2tp_init_net(struct net *net)
|
|||
return -ENOMEM;
|
||||
|
||||
INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
|
||||
rwlock_init(&pn->l2tp_tunnel_list_lock);
|
||||
spin_lock_init(&pn->l2tp_tunnel_list_lock);
|
||||
|
||||
for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
|
||||
INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
|
||||
|
||||
rwlock_init(&pn->l2tp_session_hlist_lock);
|
||||
spin_lock_init(&pn->l2tp_session_hlist_lock);
|
||||
|
||||
err = net_assign_generic(net, l2tp_net_id, pn);
|
||||
if (err)
|
||||
|
|
|
|||
Loading…
Reference in a new issue