[src/trunk]: src/sys/external/bsd/common/linux Don't wait forever to flush if...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/9c1c7d660fe3
branches:  trunk
changeset: 366349:9c1c7d660fe3
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Mon Aug 27 15:00:27 2018 +0000

description:
Don't wait forever to flush if the worker thread has no work.

diffstat:

 sys/external/bsd/common/linux/linux_work.c |  14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)

diffs (35 lines):

diff -r 731e70af7ece -r 9c1c7d660fe3 sys/external/bsd/common/linux/linux_work.c
--- a/sys/external/bsd/common/linux/linux_work.c        Mon Aug 27 14:59:58 2018 +0000
+++ b/sys/external/bsd/common/linux/linux_work.c        Mon Aug 27 15:00:27 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: linux_work.c,v 1.18 2018/08/27 14:59:58 riastradh Exp $        */
+/*     $NetBSD: linux_work.c,v 1.19 2018/08/27 15:00:27 riastradh Exp $        */
 
 /*-
  * Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_work.c,v 1.18 2018/08/27 14:59:58 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_work.c,v 1.19 2018/08/27 15:00:27 riastradh Exp $");
 
 #include <sys/types.h>
 #include <sys/atomic.h>
@@ -704,10 +704,12 @@
        uint64_t gen;
 
        mutex_enter(&wq->wq_lock);
-       gen = wq->wq_gen;
-       do {
-               cv_wait(&wq->wq_cv, &wq->wq_lock);
-       } while (gen == wq->wq_gen);
+       if (wq->wq_current_work || !TAILQ_EMPTY(&wq->wq_queue)) {
+               gen = wq->wq_gen;
+               do {
+                       cv_wait(&wq->wq_cv, &wq->wq_lock);
+               } while (gen == wq->wq_gen);
+       }
        mutex_exit(&wq->wq_lock);
 }