net: listening_hash get a spinlock per bucket
This patch prepares RCU migration of listening_hash table for
TCP/DCCP protocols.
listening_hash table being small (32 slots per protocol), we add
a spinlock for each slot, instead of a single rwlock for whole table.
This should reduce hold time of readers, and writers concurrency.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 41b3672..1cb154e 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -718,13 +718,15 @@
if (!(r->idiag_states & (TCPF_LISTEN | TCPF_SYN_RECV)))
goto skip_listen_ht;
- inet_listen_lock(hashinfo);
for (i = s_i; i < INET_LHTABLE_SIZE; i++) {
struct sock *sk;
struct hlist_node *node;
+ struct inet_listen_hashbucket *ilb;
num = 0;
- sk_for_each(sk, node, &hashinfo->listening_hash[i]) {
+ ilb = &hashinfo->listening_hash[i];
+ spin_lock_bh(&ilb->lock);
+ sk_for_each(sk, node, &ilb->head) {
struct inet_sock *inet = inet_sk(sk);
if (num < s_num) {
@@ -742,7 +744,7 @@
goto syn_recv;
if (inet_csk_diag_dump(sk, skb, cb) < 0) {
- inet_listen_unlock(hashinfo);
+ spin_unlock_bh(&ilb->lock);
goto done;
}
@@ -751,7 +753,7 @@
goto next_listen;
if (inet_diag_dump_reqs(skb, sk, cb) < 0) {
- inet_listen_unlock(hashinfo);
+ spin_unlock_bh(&ilb->lock);
goto done;
}
@@ -760,12 +762,12 @@
cb->args[4] = 0;
++num;
}
+ spin_unlock_bh(&ilb->lock);
s_num = 0;
cb->args[3] = 0;
cb->args[4] = 0;
}
- inet_listen_unlock(hashinfo);
skip_listen_ht:
cb->args[0] = 1;
s_i = num = s_num = 0;