linux-kernel - [PATCH v2 1/2] sched/wait: introduce wait_event_freezable

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Date:   Thu, 7 Feb 2019 22:29:02 +0100
From:   Hugo Lefeuvre <hle@....eu.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Greg Hartman <ghartman@...gle.com>,
        Alistair Strachan <astrachan@...gle.com>,
        Arve Hjønnevåg <arve@...roid.com>,
        Todd Kjos <tkjos@...roid.com>,
        Martijn Coenen <maco@...roid.com>,
        Christian Brauner <christian@...uner.io>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
        Joel Fernandes <joel@...lfernandes.org>
Subject: [PATCH v2 1/2] sched/wait: introduce wait_event_freezable_hrtimeout

introduce wait_event_freezable_hrtimeout, an interruptible and freezable
version of wait_event_hrtimeout.

This helper will allow for simplifications in staging/android/vsoc.c, among
others.

Signed-off-by: Hugo Lefeuvre <hle@....eu.com>
---
Changes in v2:
  - No change.

 include/linux/wait.h | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/include/linux/wait.h b/include/linux/wait.h
index 5f3efabc36f4..c4cf5113f58a 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -483,7 +483,7 @@ do {										\
 	__ret;									\
 })
 
-#define __wait_event_hrtimeout(wq_head, condition, timeout, state)		\
+#define __wait_event_hrtimeout(wq_head, condition, timeout, state, cmd)		\
 ({										\
 	int __ret = 0;								\
 	struct hrtimer_sleeper __t;						\
@@ -500,7 +500,7 @@ do {										\
 			__ret = -ETIME;						\
 			break;							\
 		}								\
-		schedule());							\
+		cmd);							        \
 										\
 	hrtimer_cancel(&__t.timer);						\
 	destroy_hrtimer_on_stack(&__t.timer);					\
@@ -529,7 +529,23 @@ do {										\
 	might_sleep();								\
 	if (!(condition))							\
 		__ret = __wait_event_hrtimeout(wq_head, condition, timeout,	\
-					       TASK_UNINTERRUPTIBLE);		\
+					       TASK_UNINTERRUPTIBLE,		\
+					       schedule());			\
+	__ret;									\
+})
+
+/*
+ * like wait_event_hrtimeout() -- except it uses TASK_INTERRUPTIBLE to avoid
+ * increasing load and is freezable.
+ */
+#define wait_event_freezable_hrtimeout(wq_head, condition, timeout)		\
+({										\
+	int __ret = 0;								\
+	might_sleep();								\
+	if (!(condition))							\
+		__ret = __wait_event_hrtimeout(wq_head, condition, timeout,	\
+					       TASK_INTERRUPTIBLE,		\
+					       freezable_schedule());		\
 	__ret;									\
 })
 
@@ -555,7 +571,8 @@ do {										\
 	might_sleep();								\
 	if (!(condition))							\
 		__ret = __wait_event_hrtimeout(wq, condition, timeout,		\
-					       TASK_INTERRUPTIBLE);		\
+					       TASK_INTERRUPTIBLE,		\
+					       schedule());			\
 	__ret;									\
 })
 
-- 
2.20.1