From bf3204cbff7d2606e758afb0994e8da6ae1c6c26 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Fri, 6 Nov 2009 21:39:07 -0800 Subject: [PATCH] Input: fix locking in memoryless force-feedback devices Now that input core acquires dev->event_lock spinlock and disables interrupts when propagating input events, using spin_lock_bh() in ff-memless driver is not allowed. Actually, the timer_lock itself is not needed anymore, we should simply use dev->event_lock as well. Also do a small cleanup in force-feedback core. Reported-by: kerneloops.org Reported-by: http://www.kerneloops.org/searchweek.php?search=ml_ff_set_gain Reported-by: Arjan van de Ven Signed-off-by: Dmitry Torokhov --- drivers/input/ff-core.c | 20 +++++++++++--------- drivers/input/ff-memless.c | 26 +++++++++++--------------- include/linux/input.h | 4 ++++ 3 files changed, 26 insertions(+), 24 deletions(-) diff --git a/drivers/input/ff-core.c b/drivers/input/ff-core.c index 72c63e5dd63..38df81fcdc3 100644 --- a/drivers/input/ff-core.c +++ b/drivers/input/ff-core.c @@ -337,16 +337,16 @@ int input_ff_create(struct input_dev *dev, int max_effects) dev->ff = ff; dev->flush = flush_effects; dev->event = input_ff_event; - set_bit(EV_FF, dev->evbit); + __set_bit(EV_FF, dev->evbit); /* Copy "true" bits into ff device bitmap */ for (i = 0; i <= FF_MAX; i++) if (test_bit(i, dev->ffbit)) - set_bit(i, ff->ffbit); + __set_bit(i, ff->ffbit); /* we can emulate RUMBLE with periodic effects */ if (test_bit(FF_PERIODIC, ff->ffbit)) - set_bit(FF_RUMBLE, dev->ffbit); + __set_bit(FF_RUMBLE, dev->ffbit); return 0; } @@ -362,12 +362,14 @@ EXPORT_SYMBOL_GPL(input_ff_create); */ void input_ff_destroy(struct input_dev *dev) { - clear_bit(EV_FF, dev->evbit); - if (dev->ff) { - if (dev->ff->destroy) - dev->ff->destroy(dev->ff); - kfree(dev->ff->private); - kfree(dev->ff); + struct ff_device *ff = dev->ff; + + __clear_bit(EV_FF, dev->evbit); + if (ff) { + if (ff->destroy) + ff->destroy(ff); + kfree(ff->private); + kfree(ff); dev->ff = NULL; } } diff --git a/drivers/input/ff-memless.c b/drivers/input/ff-memless.c index 2d1415e1683..b483b2995fa 100644 --- a/drivers/input/ff-memless.c +++ b/drivers/input/ff-memless.c @@ -61,7 +61,6 @@ struct ml_device { struct ml_effect_state states[FF_MEMLESS_EFFECTS]; int gain; struct timer_list timer; - spinlock_t timer_lock; struct input_dev *dev; int (*play_effect)(struct input_dev *dev, void *data, @@ -368,38 +367,38 @@ static void ml_effect_timer(unsigned long timer_data) { struct input_dev *dev = (struct input_dev *)timer_data; struct ml_device *ml = dev->ff->private; + unsigned long flags; debug("timer: updating effects"); - spin_lock(&ml->timer_lock); + spin_lock_irqsave(&dev->event_lock, flags); ml_play_effects(ml); - spin_unlock(&ml->timer_lock); + spin_unlock_irqrestore(&dev->event_lock, flags); } +/* + * Sets requested gain for FF effects. Called with dev->event_lock held. + */ static void ml_ff_set_gain(struct input_dev *dev, u16 gain) { struct ml_device *ml = dev->ff->private; int i; - spin_lock_bh(&ml->timer_lock); - ml->gain = gain; for (i = 0; i < FF_MEMLESS_EFFECTS; i++) __clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags); ml_play_effects(ml); - - spin_unlock_bh(&ml->timer_lock); } +/* + * Start/stop specified FF effect. Called with dev->event_lock held. + */ 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_irqsave(&ml->timer_lock, flags); if (value > 0) { debug("initiated play"); @@ -425,8 +424,6 @@ static int ml_ff_playback(struct input_dev *dev, int effect_id, int value) ml_play_effects(ml); } - spin_unlock_irqrestore(&ml->timer_lock, flags); - return 0; } @@ -436,7 +433,7 @@ static int ml_ff_upload(struct input_dev *dev, struct ml_device *ml = dev->ff->private; struct ml_effect_state *state = &ml->states[effect->id]; - spin_lock_bh(&ml->timer_lock); + spin_lock_irq(&dev->event_lock); if (test_bit(FF_EFFECT_STARTED, &state->flags)) { __clear_bit(FF_EFFECT_PLAYING, &state->flags); @@ -448,7 +445,7 @@ static int ml_ff_upload(struct input_dev *dev, ml_schedule_timer(ml); } - spin_unlock_bh(&ml->timer_lock); + spin_unlock_irq(&dev->event_lock); return 0; } @@ -482,7 +479,6 @@ int input_ff_create_memless(struct input_dev *dev, void *data, ml->private = data; ml->play_effect = play_effect; ml->gain = 0xffff; - spin_lock_init(&ml->timer_lock); setup_timer(&ml->timer, ml_effect_timer, (unsigned long)dev); set_bit(FF_GAIN, dev->ffbit); diff --git a/include/linux/input.h b/include/linux/input.h index 0ccfc30cd40..c2b1a7d244d 100644 --- a/include/linux/input.h +++ b/include/linux/input.h @@ -1377,6 +1377,10 @@ extern struct class input_class; * methods; erase() is optional. set_gain() and set_autocenter() need * only be implemented if driver sets up FF_GAIN and FF_AUTOCENTER * bits. + * + * Note that playback(), set_gain() and set_autocenter() are called with + * dev->event_lock spinlock held and interrupts off and thus may not + * sleep. */ struct ff_device { int (*upload)(struct input_dev *dev, struct ff_effect *effect,