From 8318885487792bdfccf753d6de2554c006739e10 Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Wed, 18 Jul 2018 08:18:20 +0200
Subject: [PATCH] MINOR: connection: simplify subscription by adding a
 registration function

This new function wl_set_waitcb() prepopulates a wait_list with a tasklet
and a context and returns it so that it can be passed to ->subscribe() to
be added to a connection or conn_stream's wait_list. The caller doesn't
need to know all the insiders details anymore this way.
---
 include/proto/connection.h |    9 +++++++++
 src/checks.c               |    6 +-----
 src/stream_interface.c     |   10 +++-------
 3 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/include/proto/connection.h b/include/proto/connection.h
index a2580f1..8344c95 100644
--- a/include/proto/connection.h
+++ b/include/proto/connection.h
@@ -773,6 +773,15 @@ static inline void cs_attach(struct conn_stream *cs, void *data, const struct da
 	cs->data = data;
 }
 
+static inline struct wait_list *wl_set_waitcb(struct wait_list *wl, struct task *(*cb)(struct task *, void *, unsigned short), void *ctx)
+{
+	if (!wl->task->process) {
+		wl->task->process = cb;
+		wl->task->context = ctx;
+	}
+	return wl;
+}
+
 /* Installs the connection's mux layer for upper context <ctx>.
  * Returns < 0 on error.
  */
diff --git a/src/checks.c b/src/checks.c
index 624a065..af6ddd4 100644
--- a/src/checks.c
+++ b/src/checks.c
@@ -779,11 +779,7 @@ static void __event_srv_chk_w(struct conn_stream *cs)
 			goto out_wakeup;
 		}
 		if (b_data(&check->bo)) {
-			if (!cs->wait_list.task->process) {
-				cs->wait_list.task->process = event_srv_chk_w;
-				cs->wait_list.task->context = cs;
-			}
-			conn->mux->subscribe(cs, SUB_CAN_SEND, &cs->wait_list);
+			conn->mux->subscribe(cs, SUB_CAN_SEND, wl_set_waitcb(&cs->wait_list, event_srv_chk_w, cs));
 			goto out;
 		}
 	}
diff --git a/src/stream_interface.c b/src/stream_interface.c
index 6fb7b53..f1b52c1 100644
--- a/src/stream_interface.c
+++ b/src/stream_interface.c
@@ -732,13 +732,9 @@ static struct task * si_cs_send(struct task *t, void *ctx, unsigned short state)
 		}
 	}
 	/* We couldn't send all of our data, let the mux know we'd like to send more */
-	if (co_data(oc)) {
-		if (!cs->wait_list.task->process) {
-			cs->wait_list.task->process = si_cs_send;
-			cs->wait_list.task->context = ctx;
-		}
-		conn->mux->subscribe(cs, SUB_CAN_SEND, &cs->wait_list);
-	}
+	if (co_data(oc))
+		conn->mux->subscribe(cs, SUB_CAN_SEND, wl_set_waitcb(&cs->wait_list, si_cs_send, ctx));
+
 wake_others:
 	/* Maybe somebody was waiting for this conn_stream, wake them */
 	if (did_send) {
-- 
1.7.10.4