tcp/dccp: install syn_recv requests into ehash table

In this patch, we insert request sockets into TCP/DCCP
regular ehash table (where ESTABLISHED and TIMEWAIT sockets
are) instead of using the per listener hash table.

ACK packets find SYN_RECV pseudo sockets without having
to find and lock the listener.

In nominal conditions, this halves pressure on listener lock.

Note that this will allow for SO_REUSEPORT refinements,
so that we can select a listener using cpu/numa affinities instead
of the prior 'consistent hash', since only SYN packets will
apply this selection logic.

We will shrink listen_sock in the following patch to ease
code review.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ying Cai <ycai@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 67 deletions

diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index ea915aa5e4e2..5d1c7cee2cb2 100644
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -94,73 +94,6 @@ struct dst_entry *inet6_csk_route_req(const struct sock *sk,
 }
 EXPORT_SYMBOL(inet6_csk_route_req);
 
-/*
- * request_sock (formerly open request) hash tables.
- */
-static u32 inet6_synq_hash(const struct in6_addr *raddr, const __be16 rport,
-                           const u32 rnd, const u32 synq_hsize)
-{
-        u32 c;
-
-        c = jhash_3words((__force u32)raddr->s6_addr32[0],
-                         (__force u32)raddr->s6_addr32[1],
-                         (__force u32)raddr->s6_addr32[2],
-                         rnd);
-
-        c = jhash_2words((__force u32)raddr->s6_addr32[3],
-                         (__force u32)rport,
-                         c);
-
-        return c & (synq_hsize - 1);
-}
-
-struct request_sock *inet6_csk_search_req(struct sock *sk,
-                                          const __be16 rport,
-                                          const struct in6_addr *raddr,
-                                          const struct in6_addr *laddr,
-                                          const int iif)
-{
-        struct inet_connection_sock *icsk = inet_csk(sk);
-        struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
-        struct request_sock *req;
-        u32 hash = inet6_synq_hash(raddr, rport, lopt->hash_rnd,
-                                   lopt->nr_table_entries);
-
-        spin_lock(&icsk->icsk_accept_queue.syn_wait_lock);
-        for (req = lopt->syn_table[hash]; req != NULL; req = req->dl_next) {
-                const struct inet_request_sock *ireq = inet_rsk(req);
-
-                if (ireq->ir_rmt_port == rport &&
-                    req->rsk_ops->family == AF_INET6 &&
-                    ipv6_addr_equal(&ireq->ir_v6_rmt_addr, raddr) &&
-                    ipv6_addr_equal(&ireq->ir_v6_loc_addr, laddr) &&
-                    (!ireq->ir_iif || ireq->ir_iif == iif)) {
-                        atomic_inc(&req->rsk_refcnt);
-                        WARN_ON(req->sk != NULL);
-                        break;
-                }
-        }
-        spin_unlock(&icsk->icsk_accept_queue.syn_wait_lock);
-
-        return req;
-}
-EXPORT_SYMBOL_GPL(inet6_csk_search_req);
-
-void inet6_csk_reqsk_queue_hash_add(struct sock *sk,
-                                    struct request_sock *req,
-                                    const unsigned long timeout)
-{
-        struct inet_connection_sock *icsk = inet_csk(sk);
-        struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
-        const u32 h = inet6_synq_hash(&inet_rsk(req)->ir_v6_rmt_addr,
-                                      inet_rsk(req)->ir_rmt_port,
-                                      lopt->hash_rnd, lopt->nr_table_entries);
-
-        reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
-        inet_csk_reqsk_queue_added(sk);
-}
-EXPORT_SYMBOL_GPL(inet6_csk_reqsk_queue_hash_add);
-
 void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
 {
         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) uaddr;