admin/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2025-12-07 20:06:24 +00:00
Code Issues Packages Projects Releases Wiki Activity

neighbour: Drop read_lock_bh(&tbl->lock) in pneigh_lookup().

Browse Source 
Now, all callers of pneigh_lookup() are under RCU, and the read
lock there is no longer needed.

Let's drop the lock, inline __pneigh_lookup_1() to pneigh_lookup(),
and call it from pneigh_create().

The next patch will remove tbl->lock from pneigh_create().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250716221221.442239-14-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Kuniyuki Iwashima
2025-07-16 22:08:18 +00:00
committed by Jakub Kicinski
parent dd103c9a53
commit b8b7ed1ea8
1 changed files with 16 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
net/core/neighbour.c
View File

@@ -720,23 +720,6 @@ static u32 pneigh_hash(const void *pkey, unsigned int key_len)
return hash_val;
}
static struct pneigh_entry *__pneigh_lookup_1(struct pneigh_entry *n,
struct net *net,
const void *pkey,
unsigned int key_len,
struct net_device *dev)
{
while (n) {
if (!memcmp(n->key, pkey, key_len) &&
net_eq(pneigh_net(n), net) &&
(n->dev == dev || !n->dev))
return n;
n = rcu_dereference_protected(n->next, 1);
}
return NULL;
}
struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl,
struct net *net, const void *pkey,
struct net_device *dev)
@@ -747,13 +730,19 @@ struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl,
key_len = tbl->key_len;
hash_val = pneigh_hash(pkey, key_len);
n = rcu_dereference_check(tbl->phash_buckets[hash_val],
lockdep_is_held(&tbl->lock));
read_lock_bh(&tbl->lock);
n = __pneigh_lookup_1(rcu_dereference_protected(tbl->phash_buckets[hash_val], 1),
net, pkey, key_len, dev);
read_unlock_bh(&tbl->lock);
while (n) {
if (!memcmp(n->key, pkey, key_len) &&
net_eq(pneigh_net(n), net) &&
(n->dev == dev || !n->dev))
return n;
return n;
n = rcu_dereference_check(n->next, lockdep_is_held(&tbl->lock));
}
return NULL;
}
EXPORT_IPV6_MOD(pneigh_lookup);
@@ -762,19 +751,18 @@ struct pneigh_entry *pneigh_create(struct neigh_table *tbl,
struct net_device *dev)
{
struct pneigh_entry *n;
unsigned int key_len = tbl->key_len;
u32 hash_val = pneigh_hash(pkey, key_len);
unsigned int key_len;
u32 hash_val;
ASSERT_RTNL();
read_lock_bh(&tbl->lock);
n = __pneigh_lookup_1(rcu_dereference_protected(tbl->phash_buckets[hash_val], 1),
net, pkey, key_len, dev);
n = pneigh_lookup(tbl, net, pkey, dev);
read_unlock_bh(&tbl->lock);
if (n)
goto out;
key_len = tbl->key_len;
n = kzalloc(sizeof(*n) + key_len, GFP_KERNEL);
if (!n)
goto out;
@@ -791,6 +779,7 @@ struct pneigh_entry *pneigh_create(struct neigh_table *tbl,
goto out;
}
hash_val = pneigh_hash(pkey, key_len);
write_lock_bh(&tbl->lock);
n->next = tbl->phash_buckets[hash_val];
rcu_assign_pointer(tbl->phash_buckets[hash_val], n);