linux-kernel - [PATCH] input: replace spin_lock_bh with spin_lock_irqsave in ml_ff

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Date:	Sun, 23 Nov 2008 17:02:47 -0800
From:	Arjan van de Ven <arjan@...radead.org>
To:	linux-kernel@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, anssi.hannula@...il.com,
	akpm@...ux-foundation.org, dtor@...l.ru
Subject: [PATCH] input: replace spin_lock_bh with spin_lock_irqsave in
 ml_ff_playback


>From 829678fc4684defcef2139182e88a304acdfa0ad Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@...ux.intel.com>
Date: Sun, 23 Nov 2008 16:57:36 -0800
Subject: [PATCH] input: replace spin_lock_bh with spin_lock_irqsave in ml_ff_playback

ml_ff_playback() uses spin_(un)lock_bh. However this function is called
with interrupts disabled from erase_effect() in drivers/input/ff-core.c:196.

This is not permitted, and will result in a WARN_ON in the bottom half handling code.
This patch changes this function to just use spin_lock_irqsave() instead, solving
the problem and simplifying the locking logic.

This was reported as entry #106559 in kerneloops.org

Reported-by: kerneloops.org
Signed-off-by: Arjan van de Ven <arjan@...ux.intel.com>
---
 drivers/input/ff-memless.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/input/ff-memless.c b/drivers/input/ff-memless.c
index 6790e97..bc4e40f 100644
--- a/drivers/input/ff-memless.c
+++ b/drivers/input/ff-memless.c
@@ -397,8 +397,9 @@ static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
 {
 	struct ml_device *ml = dev->ff->private;
 	struct ml_effect_state *state = &ml->states[effect_id];
+	unsigned long flags;
 
-	spin_lock_bh(&ml->timer_lock);
+	spin_lock_irqsave(&ml->timer_lock, flags);
 
 	if (value > 0) {
 		debug("initiated play");
@@ -424,7 +425,7 @@ static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
 		ml_play_effects(ml);
 	}
 
-	spin_unlock_bh(&ml->timer_lock);
+	spin_unlock_irqrestore(&ml->timer_lock, flags);
 
 	return 0;
 }
-- 
1.6.0.3


-- 
Arjan van de Ven 	Intel Open Source Technology Centre
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