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>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index bd5e8d10893f..83b3d0b8c481 100644
--- 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)