[AF_UNIX]: Use spinlock for unix_table_lock
This lock is actually taken mostly as a writer,
so using a rwlock actually just makes performance
worse especially on chips like the Intel P4.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index b5d785a..3f302ae 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -13,7 +13,7 @@
#define UNIX_HASH_SIZE 256
extern struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
-extern rwlock_t unix_table_lock;
+extern spinlock_t unix_table_lock;
extern atomic_t unix_tot_inflight;
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 1dc3685..04e850e 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -121,7 +121,7 @@
int sysctl_unix_max_dgram_qlen = 10;
struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
-DEFINE_RWLOCK(unix_table_lock);
+DEFINE_SPINLOCK(unix_table_lock);
static atomic_t unix_nr_socks = ATOMIC_INIT(0);
#define unix_sockets_unbound (&unix_socket_table[UNIX_HASH_SIZE])
@@ -130,7 +130,7 @@
/*
* SMP locking strategy:
- * hash table is protected with rwlock unix_table_lock
+ * hash table is protected with spinlock unix_table_lock
* each socket state is protected by separate rwlock.
*/
@@ -214,16 +214,16 @@
static inline void unix_remove_socket(struct sock *sk)
{
- write_lock(&unix_table_lock);
+ spin_lock(&unix_table_lock);
__unix_remove_socket(sk);
- write_unlock(&unix_table_lock);
+ spin_unlock(&unix_table_lock);
}
static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
{
- write_lock(&unix_table_lock);
+ spin_lock(&unix_table_lock);
__unix_insert_socket(list, sk);
- write_unlock(&unix_table_lock);
+ spin_unlock(&unix_table_lock);
}
static struct sock *__unix_find_socket_byname(struct sockaddr_un *sunname,
@@ -250,11 +250,11 @@
{
struct sock *s;
- read_lock(&unix_table_lock);
+ spin_lock(&unix_table_lock);
s = __unix_find_socket_byname(sunname, len, type, hash);
if (s)
sock_hold(s);
- read_unlock(&unix_table_lock);
+ spin_unlock(&unix_table_lock);
return s;
}
@@ -263,7 +263,7 @@
struct sock *s;
struct hlist_node *node;
- read_lock(&unix_table_lock);
+ spin_lock(&unix_table_lock);
sk_for_each(s, node,
&unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
struct dentry *dentry = unix_sk(s)->dentry;
@@ -276,7 +276,7 @@
}
s = NULL;
found:
- read_unlock(&unix_table_lock);
+ spin_unlock(&unix_table_lock);
return s;
}
@@ -642,12 +642,12 @@
addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
addr->hash = unix_hash_fold(csum_partial((void*)addr->name, addr->len, 0));
- write_lock(&unix_table_lock);
+ spin_lock(&unix_table_lock);
ordernum = (ordernum+1)&0xFFFFF;
if (__unix_find_socket_byname(addr->name, addr->len, sock->type,
addr->hash)) {
- write_unlock(&unix_table_lock);
+ spin_unlock(&unix_table_lock);
/* Sanity yield. It is unusual case, but yet... */
if (!(ordernum&0xFF))
yield();
@@ -658,7 +658,7 @@
__unix_remove_socket(sk);
u->addr = addr;
__unix_insert_socket(&unix_socket_table[addr->hash], sk);
- write_unlock(&unix_table_lock);
+ spin_unlock(&unix_table_lock);
err = 0;
out: up(&u->readsem);
@@ -791,7 +791,7 @@
addr->hash = UNIX_HASH_SIZE;
}
- write_lock(&unix_table_lock);
+ spin_lock(&unix_table_lock);
if (!sunaddr->sun_path[0]) {
err = -EADDRINUSE;
@@ -814,7 +814,7 @@
__unix_insert_socket(list, sk);
out_unlock:
- write_unlock(&unix_table_lock);
+ spin_unlock(&unix_table_lock);
out_up:
up(&u->readsem);
out:
@@ -1916,7 +1916,7 @@
static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
{
- read_lock(&unix_table_lock);
+ spin_lock(&unix_table_lock);
return *pos ? unix_seq_idx(seq->private, *pos - 1) : ((void *) 1);
}
@@ -1931,7 +1931,7 @@
static void unix_seq_stop(struct seq_file *seq, void *v)
{
- read_unlock(&unix_table_lock);
+ spin_unlock(&unix_table_lock);
}
static int unix_seq_show(struct seq_file *seq, void *v)
diff --git a/net/unix/garbage.c b/net/unix/garbage.c
index 6ffc64e..411802b 100644
--- a/net/unix/garbage.c
+++ b/net/unix/garbage.c
@@ -182,7 +182,7 @@
if (down_trylock(&unix_gc_sem))
return;
- read_lock(&unix_table_lock);
+ spin_lock(&unix_table_lock);
forall_unix_sockets(i, s)
{
@@ -301,7 +301,7 @@
}
u->gc_tree = GC_ORPHAN;
}
- read_unlock(&unix_table_lock);
+ spin_unlock(&unix_table_lock);
/*
* Here we are. Hitlist is filled. Die.