From 4c5891e354c382c6095264883af6744086777d76 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Wed, 26 Dec 2018 17:35:49 -0800
Subject: [PATCH] ircd::ctx: Block the caller after submit when parallel
 saturated.

---
 include/ircd/ctx/parallel.h | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/ircd/ctx/parallel.h b/include/ircd/ctx/parallel.h
index b12a7446c..1fc7cf7a2 100644
--- a/include/ircd/ctx/parallel.h
+++ b/include/ircd/ctx/parallel.h
@@ -66,32 +66,34 @@ template<class arg>
 void
 ircd::ctx::parallel<arg>::operator()(const arg &a)
 {
-	wait_avail();
 	if(this->eptr)
 		std::rethrow_exception(this->eptr);
 
 	this->a.at(snd++) = a;
 	snd %= this->a.size();
-	out++;
 
 	auto &p(*this->p);
 	p(std::bind(&parallel::receiver, this));
+
+	out++;
+	wait_avail();
 }
 
 template<class arg>
 void
 ircd::ctx::parallel<arg>::operator()()
 {
-	wait_avail();
 	if(this->eptr)
 		std::rethrow_exception(this->eptr);
 
 	snd++;
 	snd %= this->a.size();
-	out++;
 
 	auto &p(*this->p);
 	p(std::bind(&parallel::receiver, this));
+
+	out++;
+	wait_avail();
 }
 
 template<class arg>