Change the top level list of neighbor tables to use RCU.
Minor change to BUG() if a neighbor table is registered twice.
Signed-off-by: Stephen Hemminger <[EMAIL PROTECTED]>
---
include/net/neighbour.h | 2 -
net/core/neighbour.c | 89 ++++++++++++++++++++++--------------------------
2 files changed, 42 insertions(+), 49 deletions(-)
--- net-2.6.19.orig/net/core/neighbour.c
+++ net-2.6.19/net/core/neighbour.c
@@ -61,7 +61,7 @@ static void neigh_app_notify(struct neig
static int pneigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
-static struct neigh_table *neigh_tables;
+static LIST_HEAD(neigh_tables);
#ifdef CONFIG_PROC_FS
static struct file_operations neigh_stat_seq_fops;
#endif
@@ -93,11 +93,11 @@ static struct file_operations neigh_stat
It is supposed, that dev->hard_header is simplistic and does
not make callbacks to neighbour tables.
- The last lock is neigh_tbl_lock. It is pure SMP lock, protecting
- list of neighbour tables. This list is used only in process context,
+ The last lock is neigh_tbl_lock. It controls update to the
+ set of neighbor tables. Typically used during initialization
*/
-static DEFINE_RWLOCK(neigh_tbl_lock);
+static DEFINE_SPINLOCK(neigh_tbl_lock);
static int neigh_blackhole(struct sk_buff *skb)
{
@@ -1391,26 +1391,18 @@ void neigh_table_init(struct neigh_table
struct neigh_table *tmp;
neigh_table_init_no_netlink(tbl);
- write_lock(&neigh_tbl_lock);
- for (tmp = neigh_tables; tmp; tmp = tmp->next) {
- if (tmp->family == tbl->family)
- break;
- }
- tbl->next = neigh_tables;
- neigh_tables = tbl;
- write_unlock(&neigh_tbl_lock);
-
- if (unlikely(tmp)) {
- printk(KERN_ERR "NEIGH: Registering multiple tables for "
- "family %d\n", tbl->family);
- dump_stack();
+
+ spin_lock(&neigh_tbl_lock);
+ list_for_each_entry(tmp, &neigh_tables, list) {
+ BUG_ON(tmp->family == tbl->family);
}
+
+ list_add_rcu(&tbl->list, &neigh_tables);
+ spin_unlock(&neigh_tbl_lock);
}
int neigh_table_clear(struct neigh_table *tbl)
{
- struct neigh_table **tp;
-
/* It is not clean... Fix it to unload IPv6 module safely */
del_timer_sync(&tbl->gc_timer);
del_timer_sync(&tbl->proxy_timer);
@@ -1418,14 +1410,12 @@ int neigh_table_clear(struct neigh_table
neigh_ifdown(tbl, NULL);
if (atomic_read(&tbl->entries))
printk(KERN_CRIT "neighbour leakage\n");
- write_lock(&neigh_tbl_lock);
- for (tp = &neigh_tables; *tp; tp = &(*tp)->next) {
- if (*tp == tbl) {
- *tp = tbl->next;
- break;
- }
- }
- write_unlock(&neigh_tbl_lock);
+
+ spin_lock(&neigh_tbl_lock);
+ list_del_rcu(&tbl->list);
+ spin_unlock(&neigh_tbl_lock);
+
+ synchronize_rcu();
neigh_hash_free(tbl->hash_buckets, tbl->hash_mask + 1);
tbl->hash_buckets = NULL;
@@ -1460,13 +1450,12 @@ int neigh_delete(struct sk_buff *skb, st
}
}
- read_lock(&neigh_tbl_lock);
- for (tbl = neigh_tables; tbl; tbl = tbl->next) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(tbl, &neigh_tables, list) {
struct neighbour *neigh;
if (tbl->family != ndm->ndm_family)
continue;
- read_unlock(&neigh_tbl_lock);
if (nla_len(dst_attr) < tbl->key_len)
goto out_dev_put;
@@ -1491,12 +1480,12 @@ int neigh_delete(struct sk_buff *skb, st
neigh_release(neigh);
goto out_dev_put;
}
- read_unlock(&neigh_tbl_lock);
err = -EAFNOSUPPORT;
out_dev_put:
if (dev)
dev_put(dev);
+ rcu_read_unlock();
out:
return err;
}
@@ -1529,15 +1518,14 @@ int neigh_add(struct sk_buff *skb, struc
goto out_dev_put;
}
- read_lock(&neigh_tbl_lock);
- for (tbl = neigh_tables; tbl; tbl = tbl->next) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(tbl, &neigh_tables, list) {
int flags = NEIGH_UPDATE_F_ADMIN | NEIGH_UPDATE_F_OVERRIDE;
struct neighbour *neigh;
void *dst, *lladdr;
if (tbl->family != ndm->ndm_family)
continue;
- read_unlock(&neigh_tbl_lock);
if (nla_len(tb[NDA_DST]) < tbl->key_len)
goto out_dev_put;
@@ -1582,12 +1570,12 @@ int neigh_add(struct sk_buff *skb, struc
goto out_dev_put;
}
- read_unlock(&neigh_tbl_lock);
err = -EAFNOSUPPORT;
out_dev_put:
if (dev)
dev_put(dev);
+ rcu_read_unlock();
out:
return err;
}
@@ -1792,8 +1780,8 @@ int neightbl_set(struct sk_buff *skb, st
}
ndtmsg = nlmsg_data(nlh);
- read_lock(&neigh_tbl_lock);
- for (tbl = neigh_tables; tbl; tbl = tbl->next) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(tbl, &neigh_tables, list) {
if (ndtmsg->ndtm_family && tbl->family != ndtmsg->ndtm_family)
continue;
@@ -1893,26 +1881,26 @@ int neightbl_set(struct sk_buff *skb, st
errout_tbl_lock:
write_unlock_bh(&tbl->lock);
errout_locked:
- read_unlock(&neigh_tbl_lock);
+ rcu_read_unlock();
errout:
return err;
}
int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
{
- int family, tidx, nidx = 0;
+ int family, tidx = 0, nidx = 0;
int tbl_skip = cb->args[0];
int neigh_skip = cb->args[1];
struct neigh_table *tbl;
family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family;
- read_lock(&neigh_tbl_lock);
- for (tbl = neigh_tables, tidx = 0; tbl; tbl = tbl->next, tidx++) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(tbl, &neigh_tables, list) {
struct neigh_parms *p;
if (tidx < tbl_skip || (family && tbl->family != family))
- continue;
+ goto next_tbl;
if (neightbl_fill_info(skb, tbl, NETLINK_CB(cb->skb).pid,
cb->nlh->nlmsg_seq, RTM_NEWNEIGHTBL,
@@ -1932,9 +1920,11 @@ int neightbl_dump_info(struct sk_buff *s
}
neigh_skip = 0;
+next_tbl:
+ ++tidx;
}
out:
- read_unlock(&neigh_tbl_lock);
+ rcu_read_unlock();
cb->args[0] = tidx;
cb->args[1] = nidx;
@@ -2024,22 +2014,25 @@ out:
int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
{
struct neigh_table *tbl;
- int t, family, s_t;
+ int t = 0, family, s_t;
+
- read_lock(&neigh_tbl_lock);
family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family;
s_t = cb->args[0];
- for (tbl = neigh_tables, t = 0; tbl; tbl = tbl->next, t++) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(tbl, &neigh_tables, list) {
if (t < s_t || (family && tbl->family != family))
- continue;
+ goto next;
if (t > s_t)
memset(&cb->args[1], 0, sizeof(cb->args) -
sizeof(cb->args[0]));
if (neigh_dump_table(tbl, skb, cb) < 0)
break;
+next:
+ ++t;
}
- read_unlock(&neigh_tbl_lock);
+ rcu_read_unlock();
cb->args[0] = t;
return skb->len;
--- net-2.6.19.orig/include/net/neighbour.h
+++ net-2.6.19/include/net/neighbour.h
@@ -136,7 +136,7 @@ struct pneigh_entry
struct neigh_table
{
- struct neigh_table *next;
+ struct list_head list;
int family;
int entry_size;
int key_len;
--
-
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