linux-kernel - [PATCH 4/35] W1: w1_process, allow wakeup in sleep

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Date:	Fri, 28 Mar 2008 07:24:41 -0500
From:	David Fries <david@...es.net>
To:	linux-kernel@...r.kernel.org
Cc:	Evgeniy Polyakov <johnpol@....mipt.ru>
Subject: [PATCH 4/35] W1: w1_process, allow wakeup in sleep

w1.c 1.7 1.8
msleep_interruptible only wakes for signals, but we don't use them.
We want kthread_stop to wake it up, so call schedule_timeout
ourselves.  This is prep-work for blocking when there isn't anything            to do, instead of sleeping in a loop, as something has to be able to
wake it up.
Added a check for termination after the bus search, otherwise it would
sleep for the full time value if kthread_stop was called while
w1_process was in the bus search.  This would cause a deadlock when it
is blocking instead of sleeping with a timeout.

Signed-off-by: David Fries <david@...es.net>
---
 drivers/w1/w1.c |   11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 9a09f3a..ad89d85 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -810,6 +810,10 @@ void w1_search_process(struct w1_master *dev, u8 search_type)
 int w1_process(void *data)
 {
 	struct w1_master *dev = (struct w1_master *) data;
+	/* As long as w1_timeout is only set by a module parameter the sleep
+	 * time can be calculated in jiffies once.
+	 */
+	const unsigned long jtime=msecs_to_jiffies(w1_timeout * 1000);
 
 	while (!kthread_should_stop() && !test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 		if(dev->search_count) {
@@ -819,7 +823,12 @@ int w1_process(void *data)
 		}
 
 		try_to_freeze();
-		msleep_interruptible(w1_timeout * 1000);
+		__set_current_state(TASK_INTERRUPTIBLE);
+
+		if(kthread_should_stop() || test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
+			break;
+
+		schedule_timeout(jtime);
 	}
 
 	atomic_dec(&dev->refcnt);
-- 
1.4.4.4

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