Input: fix locking in force-feedback core

The newly added event_lock spinlock in the input core disallows sleeping
and therefore using mutexes in event handlers. Convert force-feedback
core to rely on event_lock instead of mutex to protect slots allocated
for fore-feedback effects. The original mutex is still used to serialize
uploading and erasing of effects.

Reported-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/input/ff-core.c b/drivers/input/ff-core.c
index eebc724..4c01464 100644 (file)
--- a/drivers/input/ff-core.c
+++ b/drivers/input/ff-core.c
@@ -166,8 +166,10 @@ int input_ff_upload(struct input_dev *dev, struct ff_effect *effect,
        if (ret)
                goto out;
 
+       spin_lock_irq(&dev->event_lock);
        ff->effects[id] = *effect;
        ff->effect_owners[id] = file;
+       spin_unlock_irq(&dev->event_lock);
 
  out:
        mutex_unlock(&ff->mutex);
@@ -189,16 +191,22 @@ static int erase_effect(struct input_dev *dev, int effect_id,
        if (error)
                return error;
 
+       spin_lock_irq(&dev->event_lock);
        ff->playback(dev, effect_id, 0);
+       ff->effect_owners[effect_id] = NULL;
+       spin_unlock_irq(&dev->event_lock);
 
        if (ff->erase) {
                error = ff->erase(dev, effect_id);
-               if (error)
+               if (error) {
+                       spin_lock_irq(&dev->event_lock);
+                       ff->effect_owners[effect_id] = file;
+                       spin_unlock_irq(&dev->event_lock);
+
                        return error;
+               }
        }
 
-       ff->effect_owners[effect_id] = NULL;
-
        return 0;
 }
 
@@ -263,8 +271,6 @@ int input_ff_event(struct input_dev *dev, unsigned int type,
        if (type != EV_FF)
                return 0;
 
-       mutex_lock(&ff->mutex);
-
        switch (code) {
        case FF_GAIN:
                if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffff)
@@ -286,7 +292,6 @@ int input_ff_event(struct input_dev *dev, unsigned int type,
                break;
        }
 
-       mutex_unlock(&ff->mutex);
        return 0;
 }
 EXPORT_SYMBOL_GPL(input_ff_event);