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>

1 files changed, 11 insertions, 6 deletions

diff --git a/drivers/input/ff-core.c b/drivers/input/ff-core.c
index eebc72465fc9..4c01464ec8f3 100644
--- 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);