tcp: relax listening_hash operations

softirq handlers use RCU protection to lookup listeners,
and write operations all happen from process context.
We do not need to block BH for dump operations.

Also SYN_RECV since request sockets are stored in the ehash table :

 1) inet_diag_dump_icsk() no longer need to clear
    cb->args[3] and cb->args[4] that were used as cursors while
    iterating the old per listener hash table.

 2) Also factorize a test : No need to scan listening_hash[]
    if r->id.idiag_dport is not zero.

Signed-off-by: Eric Dumazet <edumazet@google.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 e4d16fc5bbb3fec077f8e3bb3ff8811a66046edc..0a1d4a896a261dcb67e69a2d8c9aff83332fadd7 100644 (file)
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -863,7 +863,7 @@ void inet_diag_dump_icsk(struct inet_hashinfo *hashinfo, struct sk_buff *skb,
        s_num = num = cb->args[2];
 
        if (cb->args[0] == 0) {
-               if (!(idiag_states & TCPF_LISTEN))
+               if (!(idiag_states & TCPF_LISTEN) || r->id.idiag_dport)
                        goto skip_listen_ht;
 
                for (i = s_i; i < INET_LHTABLE_SIZE; i++) {
@@ -872,7 +872,7 @@ void inet_diag_dump_icsk(struct inet_hashinfo *hashinfo, struct sk_buff *skb,
 
                        num = 0;
                        ilb = &hashinfo->listening_hash[i];
-                       spin_lock_bh(&ilb->lock);
+                       spin_lock(&ilb->lock);
                        sk_for_each(sk, &ilb->head) {
                                struct inet_sock *inet = inet_sk(sk);
 
@@ -892,26 +892,18 @@ void inet_diag_dump_icsk(struct inet_hashinfo *hashinfo, struct sk_buff *skb,
                                    r->id.idiag_sport)
                                        goto next_listen;
 
-                               if (r->id.idiag_dport ||
-                                   cb->args[3] > 0)
-                                       goto next_listen;
-
                                if (inet_csk_diag_dump(sk, skb, cb, r,
                                                       bc, net_admin) < 0) {
-                                       spin_unlock_bh(&ilb->lock);
+                                       spin_unlock(&ilb->lock);
                                        goto done;
                                }
 
 next_listen:
-                               cb->args[3] = 0;
-                               cb->args[4] = 0;
                                ++num;
                        }
-                       spin_unlock_bh(&ilb->lock);
+                       spin_unlock(&ilb->lock);
 
                        s_num = 0;
-                       cb->args[3] = 0;
-                       cb->args[4] = 0;
                }
 skip_listen_ht:
                cb->args[0] = 1;

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index bd5e8d10893fb6abffa6b0aa65de239b0000fe5b..83b3d0b8c4812d734728360a694a596a17257d02 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1893,7 +1893,7 @@ static void *listening_get_next(struct seq_file *seq, void *cur)
        if (!sk) {
 get_head:
                ilb = &tcp_hashinfo.listening_hash[st->bucket];
-               spin_lock_bh(&ilb->lock);
+               spin_lock(&ilb->lock);
                sk = sk_head(&ilb->head);
                st->offset = 0;
                goto get_sk;
@@ -1911,7 +1911,7 @@ get_sk:
                        return sk;
                icsk = inet_csk(sk);
        }
-       spin_unlock_bh(&ilb->lock);
+       spin_unlock(&ilb->lock);
        st->offset = 0;
        if (++st->bucket < INET_LHTABLE_SIZE)
                goto get_head;
@@ -2119,7 +2119,7 @@ static void tcp_seq_stop(struct seq_file *seq, void *v)
        switch (st->state) {
        case TCP_SEQ_STATE_LISTENING:
                if (v != SEQ_START_TOKEN)
-                       spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
+                       spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
                break;
        case TCP_SEQ_STATE_ESTABLISHED:
                if (v)