inet: add rsk_listener field to struct request_sock

Once we'll be able to lookup request sockets in ehash table,
we'll need to get access to listener which created this request.

This avoid doing a lookup to find the listener, which benefits
for a more solid SO_REUSEPORT, and is needed once we no
longer queue request sock into a listener private queue.

Note that 'struct tcp_request_sock'->listener could be reduced
to a single bit, as TFO listener should match req->rsk_listener.
TFO will no longer need to hold a reference on the listener.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 3 deletions

diff --git a/include/net/request_sock.h b/include/net/request_sock.h
index 56dc2faba47e..723d1cbdf20e 100644
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -52,6 +52,7 @@ struct request_sock {
 #define rsk_refcnt                      __req_common.skc_refcnt
 
         struct request_sock             *dl_next;
+        struct sock                     *rsk_listener;
         u16                             mss;
         u8                              num_retrans; /* number of retransmits */
         u8                              cookie_ts:1; /* syncookie: encode tcpopts in timestamp */
@@ -67,13 +68,16 @@ struct request_sock {
         u32                             peer_secid;
 };
 
-static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops)
+static inline struct request_sock *
+reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener)
 {
         struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
 
-        if (req != NULL)
+        if (req) {
                 req->rsk_ops = ops;
-
+                sock_hold(sk_listener);
+                req->rsk_listener = sk_listener;
+        }
         return req;
 }
 
@@ -88,6 +92,8 @@ static inline void reqsk_free(struct request_sock *req)
         WARN_ON_ONCE(atomic_read(&req->rsk_refcnt) != 0);
 
         req->rsk_ops->destructor(req);
+        if (req->rsk_listener)
+                sock_put(req->rsk_listener);
         kmem_cache_free(req->rsk_ops->slab, req);
 }