--- zzzz-none-000/linux-3.10.107/include/net/request_sock.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/include/net/request_sock.h	2021-02-04 17:41:59.000000000 +0000
@@ -32,77 +32,100 @@
 	int		obj_size;
 	struct kmem_cache	*slab;
 	char		*slab_name;
-	int		(*rtx_syn_ack)(struct sock *sk,
+	int		(*rtx_syn_ack)(const struct sock *sk,
 				       struct request_sock *req);
-	void		(*send_ack)(struct sock *sk, struct sk_buff *skb,
+	void		(*send_ack)(const struct sock *sk, struct sk_buff *skb,
 				    struct request_sock *req);
-	void		(*send_reset)(struct sock *sk,
+	void		(*send_reset)(const struct sock *sk,
 				      struct sk_buff *skb);
 	void		(*destructor)(struct request_sock *req);
-	void		(*syn_ack_timeout)(struct sock *sk,
-					   struct request_sock *req);
+	void		(*syn_ack_timeout)(const struct request_sock *req);
 };
 
-extern int inet_rtx_syn_ack(struct sock *parent, struct request_sock *req);
+int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req);
 
 /* struct request_sock - mini sock to represent a connection request
  */
 struct request_sock {
+	struct sock_common		__req_common;
+#define rsk_refcnt			__req_common.skc_refcnt
+#define rsk_hash			__req_common.skc_hash
+#define rsk_listener			__req_common.skc_listener
+#define rsk_window_clamp		__req_common.skc_window_clamp
+#define rsk_rcv_wnd			__req_common.skc_rcv_wnd
+
 	struct request_sock		*dl_next;
 	u16				mss;
 	u8				num_retrans; /* number of retransmits */
 	u8				cookie_ts:1; /* syncookie: encode tcpopts in timestamp */
 	u8				num_timeout:7; /* number of timeouts */
-	/* The following two fields can be easily recomputed I think -AK */
-	u32				window_clamp; /* window clamp at creation time */
-	u32				rcv_wnd;	  /* rcv_wnd offered first time */
 	u32				ts_recent;
-	unsigned long			expires;
+	struct timer_list		rsk_timer;
 	const struct request_sock_ops	*rsk_ops;
 	struct sock			*sk;
+	u32				*saved_syn;
 	u32				secid;
 	u32				peer_secid;
 };
 
-static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops)
+static inline struct request_sock *inet_reqsk(struct sock *sk)
 {
-	struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
+	return (struct request_sock *)sk;
+}
 
-	if (req != NULL)
-		req->rsk_ops = ops;
+static inline struct sock *req_to_sk(struct request_sock *req)
+{
+	return (struct sock *)req;
+}
 
+static inline struct request_sock *
+reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener,
+	    bool attach_listener)
+{
+	struct request_sock *req;
+
+	req = kmem_cache_alloc(ops->slab, GFP_ATOMIC | __GFP_NOWARN);
+
+	if (req) {
+		req->rsk_ops = ops;
+		if (attach_listener) {
+			sock_hold(sk_listener);
+			req->rsk_listener = sk_listener;
+		} else {
+			req->rsk_listener = NULL;
+		}
+		req_to_sk(req)->sk_prot = sk_listener->sk_prot;
+		sk_node_init(&req_to_sk(req)->sk_node);
+		sk_tx_queue_clear(req_to_sk(req));
+		req->saved_syn = NULL;
+		/* Following is temporary. It is coupled with debugging
+		 * helpers in reqsk_put() & reqsk_free()
+		 */
+		atomic_set(&req->rsk_refcnt, 0);
+	}
 	return req;
 }
 
-static inline void __reqsk_free(struct request_sock *req)
+static inline void reqsk_free(struct request_sock *req)
 {
+	/* temporary debugging */
+	WARN_ON_ONCE(atomic_read(&req->rsk_refcnt) != 0);
+
+	req->rsk_ops->destructor(req);
+	if (req->rsk_listener)
+		sock_put(req->rsk_listener);
+	kfree(req->saved_syn);
 	kmem_cache_free(req->rsk_ops->slab, req);
 }
 
-static inline void reqsk_free(struct request_sock *req)
+static inline void reqsk_put(struct request_sock *req)
 {
-	req->rsk_ops->destructor(req);
-	__reqsk_free(req);
+	if (atomic_dec_and_test(&req->rsk_refcnt))
+		reqsk_free(req);
 }
 
 extern int sysctl_max_syn_backlog;
 
-/** struct listen_sock - listen state
- *
- * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
- */
-struct listen_sock {
-	u8			max_qlen_log;
-	u8			synflood_warned;
-	/* 2 bytes hole, try to use */
-	int			qlen;
-	int			qlen_young;
-	int			clock_hand;
-	u32			hash_rnd;
-	u32			nr_table_entries;
-	struct request_sock	*syn_table[0];
-};
-
 /*
  * For a TCP Fast Open listener -
  *	lock - protects the access to all the reqsk, which is co-owned by
@@ -136,144 +159,72 @@
  * @rskq_accept_head - FIFO head of established children
  * @rskq_accept_tail - FIFO tail of established children
  * @rskq_defer_accept - User waits for some data after accept()
- * @syn_wait_lock - serializer
- *
- * %syn_wait_lock is necessary only to avoid proc interface having to grab the main
- * lock sock while browsing the listening hash (otherwise it's deadlock prone).
  *
- * This lock is acquired in read mode only from listening_get_next() seq_file
- * op and it's acquired in write mode _only_ from code that is actively
- * changing rskq_accept_head. All readers that are holding the master sock lock
- * don't need to grab this lock in read mode too as rskq_accept_head. writes
- * are always protected from the main sock lock.
  */
 struct request_sock_queue {
+	spinlock_t		rskq_lock;
+	u8			rskq_defer_accept;
+
+	u32			synflood_warned;
+	atomic_t		qlen;
+	atomic_t		young;
+
 	struct request_sock	*rskq_accept_head;
 	struct request_sock	*rskq_accept_tail;
-	rwlock_t		syn_wait_lock;
-	u8			rskq_defer_accept;
-	/* 3 bytes hole, try to pack */
-	struct listen_sock	*listen_opt;
-	struct fastopen_queue	*fastopenq; /* This is non-NULL iff TFO has been
-					     * enabled on this listener. Check
-					     * max_qlen != 0 in fastopen_queue
-					     * to determine if TFO is enabled
-					     * right at this moment.
+	struct fastopen_queue	fastopenq;  /* Check max_qlen != 0 to determine
+					     * if TFO is enabled.
 					     */
 };
 
-extern int reqsk_queue_alloc(struct request_sock_queue *queue,
-			     unsigned int nr_table_entries);
+void reqsk_queue_alloc(struct request_sock_queue *queue);
 
-extern void __reqsk_queue_destroy(struct request_sock_queue *queue);
-extern void reqsk_queue_destroy(struct request_sock_queue *queue);
-extern void reqsk_fastopen_remove(struct sock *sk,
-				  struct request_sock *req, bool reset);
+void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req,
+			   bool reset);
 
-static inline struct request_sock *
-	reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
-{
-	struct request_sock *req = queue->rskq_accept_head;
-
-	queue->rskq_accept_head = NULL;
-	return req;
-}
-
-static inline int reqsk_queue_empty(struct request_sock_queue *queue)
+static inline bool reqsk_queue_empty(const struct request_sock_queue *queue)
 {
 	return queue->rskq_accept_head == NULL;
 }
 
-static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
-				      struct request_sock *req,
-				      struct request_sock **prev_req)
-{
-	write_lock(&queue->syn_wait_lock);
-	*prev_req = req->dl_next;
-	write_unlock(&queue->syn_wait_lock);
-}
-
-static inline void reqsk_queue_add(struct request_sock_queue *queue,
-				   struct request_sock *req,
-				   struct sock *parent,
-				   struct sock *child)
+static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue,
+						      struct sock *parent)
 {
-	req->sk = child;
-	sk_acceptq_added(parent);
-
-	if (queue->rskq_accept_head == NULL)
-		queue->rskq_accept_head = req;
-	else
-		queue->rskq_accept_tail->dl_next = req;
-
-	queue->rskq_accept_tail = req;
-	req->dl_next = NULL;
-}
-
-static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
-{
-	struct request_sock *req = queue->rskq_accept_head;
-
-	WARN_ON(req == NULL);
-
-	queue->rskq_accept_head = req->dl_next;
-	if (queue->rskq_accept_head == NULL)
-		queue->rskq_accept_tail = NULL;
+	struct request_sock *req;
 
+	spin_lock_bh(&queue->rskq_lock);
+	req = queue->rskq_accept_head;
+	if (req) {
+		sk_acceptq_removed(parent);
+		queue->rskq_accept_head = req->dl_next;
+		if (queue->rskq_accept_head == NULL)
+			queue->rskq_accept_tail = NULL;
+	}
+	spin_unlock_bh(&queue->rskq_lock);
 	return req;
 }
 
-static inline int reqsk_queue_removed(struct request_sock_queue *queue,
-				      struct request_sock *req)
+static inline void reqsk_queue_removed(struct request_sock_queue *queue,
+				       const struct request_sock *req)
 {
-	struct listen_sock *lopt = queue->listen_opt;
-
 	if (req->num_timeout == 0)
-		--lopt->qlen_young;
-
-	return --lopt->qlen;
+		atomic_dec(&queue->young);
+	atomic_dec(&queue->qlen);
 }
 
-static inline int reqsk_queue_added(struct request_sock_queue *queue)
+static inline void reqsk_queue_added(struct request_sock_queue *queue)
 {
-	struct listen_sock *lopt = queue->listen_opt;
-	const int prev_qlen = lopt->qlen;
-
-	lopt->qlen_young++;
-	lopt->qlen++;
-	return prev_qlen;
+	atomic_inc(&queue->young);
+	atomic_inc(&queue->qlen);
 }
 
 static inline int reqsk_queue_len(const struct request_sock_queue *queue)
 {
-	return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
+	return atomic_read(&queue->qlen);
 }
 
 static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
 {
-	return queue->listen_opt->qlen_young;
-}
-
-static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
-{
-	return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
-}
-
-static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
-					u32 hash, struct request_sock *req,
-					unsigned long timeout)
-{
-	struct listen_sock *lopt = queue->listen_opt;
-
-	req->expires = jiffies + timeout;
-	req->num_retrans = 0;
-	req->num_timeout = 0;
-	req->sk = NULL;
-	req->dl_next = lopt->syn_table[hash];
-
-	write_lock(&queue->syn_wait_lock);
-	lopt->syn_table[hash] = req;
-	write_unlock(&queue->syn_wait_lock);
+	return atomic_read(&queue->young);
 }
 
 #endif /* _REQUEST_SOCK_H */