Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 563 insertions, 0 deletions

diff --git a/drivers/input/ff-memless.c b/drivers/input/ff-memless.c
new file mode 100644
index 000000000..d1fefd1df
--- /dev/null
+++ b/drivers/input/ff-memless.c
@@ -0,0 +1,563 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Force feedback support for memoryless devices
+ *
+ *  Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>
+ *  Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>
+ */
+
+/* #define DEBUG */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/jiffies.h>
+#include <linux/fixp-arith.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>");
+MODULE_DESCRIPTION("Force feedback support for memoryless devices");
+
+/* Number of effects handled with memoryless devices */
+#define FF_MEMLESS_EFFECTS	16
+
+/* Envelope update interval in ms */
+#define FF_ENVELOPE_INTERVAL	50
+
+#define FF_EFFECT_STARTED	0
+#define FF_EFFECT_PLAYING	1
+#define FF_EFFECT_ABORTING	2
+
+struct ml_effect_state {
+	struct ff_effect *effect;
+	unsigned long flags;	/* effect state (STARTED, PLAYING, etc) */
+	int count;		/* loop count of the effect */
+	unsigned long play_at;	/* start time */
+	unsigned long stop_at;	/* stop time */
+	unsigned long adj_at;	/* last time the effect was sent */
+};
+
+struct ml_device {
+	void *private;
+	struct ml_effect_state states[FF_MEMLESS_EFFECTS];
+	int gain;
+	struct timer_list timer;
+	struct input_dev *dev;
+
+	int (*play_effect)(struct input_dev *dev, void *data,
+			   struct ff_effect *effect);
+};
+
+static const struct ff_envelope *get_envelope(const struct ff_effect *effect)
+{
+	static const struct ff_envelope empty_envelope;
+
+	switch (effect->type) {
+	case FF_PERIODIC:
+		return &effect->u.periodic.envelope;
+
+	case FF_CONSTANT:
+		return &effect->u.constant.envelope;
+
+	default:
+		return &empty_envelope;
+	}
+}
+
+/*
+ * Check for the next time envelope requires an update on memoryless devices
+ */
+static unsigned long calculate_next_time(struct ml_effect_state *state)
+{
+	const struct ff_envelope *envelope = get_envelope(state->effect);
+	unsigned long attack_stop, fade_start, next_fade;
+
+	if (envelope->attack_length) {
+		attack_stop = state->play_at +
+			msecs_to_jiffies(envelope->attack_length);
+		if (time_before(state->adj_at, attack_stop))
+			return state->adj_at +
+					msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
+	}
+
+	if (state->effect->replay.length) {
+		if (envelope->fade_length) {
+			/* check when fading should start */
+			fade_start = state->stop_at -
+					msecs_to_jiffies(envelope->fade_length);
+
+			if (time_before(state->adj_at, fade_start))
+				return fade_start;
+
+			/* already fading, advance to next checkpoint */
+			next_fade = state->adj_at +
+					msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
+			if (time_before(next_fade, state->stop_at))
+				return next_fade;
+		}
+
+		return state->stop_at;
+	}
+
+	return state->play_at;
+}
+
+static void ml_schedule_timer(struct ml_device *ml)
+{
+	struct ml_effect_state *state;
+	unsigned long now = jiffies;
+	unsigned long earliest = 0;
+	unsigned long next_at;
+	int events = 0;
+	int i;
+
+	pr_debug("calculating next timer\n");
+
+	for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
+
+		state = &ml->states[i];
+
+		if (!test_bit(FF_EFFECT_STARTED, &state->flags))
+			continue;
+
+		if (test_bit(FF_EFFECT_PLAYING, &state->flags))
+			next_at = calculate_next_time(state);
+		else
+			next_at = state->play_at;
+
+		if (time_before_eq(now, next_at) &&
+		    (++events == 1 || time_before(next_at, earliest)))
+			earliest = next_at;
+	}
+
+	if (!events) {
+		pr_debug("no actions\n");
+		timer_delete(&ml->timer);
+	} else {
+		pr_debug("timer set\n");
+		mod_timer(&ml->timer, earliest);
+	}
+}
+
+/*
+ * Apply an envelope to a value
+ */
+static int apply_envelope(struct ml_effect_state *state, int value,
+			  struct ff_envelope *envelope)
+{
+	struct ff_effect *effect = state->effect;
+	unsigned long now = jiffies;
+	int time_from_level;
+	int time_of_envelope;
+	int envelope_level;
+	int difference;
+
+	if (envelope->attack_length &&
+	    time_before(now,
+			state->play_at + msecs_to_jiffies(envelope->attack_length))) {
+		pr_debug("value = 0x%x, attack_level = 0x%x\n",
+			 value, envelope->attack_level);
+		time_from_level = jiffies_to_msecs(now - state->play_at);
+		time_of_envelope = envelope->attack_length;
+		envelope_level = min_t(u16, envelope->attack_level, 0x7fff);
+
+	} else if (envelope->fade_length && effect->replay.length &&
+		   time_after(now,
+			      state->stop_at - msecs_to_jiffies(envelope->fade_length)) &&
+		   time_before(now, state->stop_at)) {
+		time_from_level = jiffies_to_msecs(state->stop_at - now);
+		time_of_envelope = envelope->fade_length;
+		envelope_level = min_t(u16, envelope->fade_level, 0x7fff);
+	} else
+		return value;
+
+	difference = abs(value) - envelope_level;
+
+	pr_debug("difference = %d\n", difference);
+	pr_debug("time_from_level = 0x%x\n", time_from_level);
+	pr_debug("time_of_envelope = 0x%x\n", time_of_envelope);
+
+	difference = difference * time_from_level / time_of_envelope;
+
+	pr_debug("difference = %d\n", difference);
+
+	return value < 0 ?
+		-(difference + envelope_level) : (difference + envelope_level);
+}
+
+/*
+ * Return the type the effect has to be converted into (memless devices)
+ */
+static int get_compatible_type(struct ff_device *ff, int effect_type)
+{
+
+	if (test_bit(effect_type, ff->ffbit))
+		return effect_type;
+
+	if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit))
+		return FF_RUMBLE;
+
+	pr_err("invalid type in get_compatible_type()\n");
+
+	return 0;
+}
+
+/*
+ * Only left/right direction should be used (under/over 0x8000) for
+ * forward/reverse motor direction (to keep calculation fast & simple).
+ */
+static u16 ml_calculate_direction(u16 direction, u16 force,
+				  u16 new_direction, u16 new_force)
+{
+	if (!force)
+		return new_direction;
+	if (!new_force)
+		return direction;
+	return (((u32)(direction >> 1) * force +
+		 (new_direction >> 1) * new_force) /
+		(force + new_force)) << 1;
+}
+
+#define FRAC_N 8
+static inline s16 fixp_new16(s16 a)
+{
+	return ((s32)a) >> (16 - FRAC_N);
+}
+
+static inline s16 fixp_mult(s16 a, s16 b)
+{
+	a = ((s32)a * 0x100) / 0x7fff;
+	return ((s32)(a * b)) >> FRAC_N;
+}
+
+/*
+ * Combine two effects and apply gain.
+ */
+static void ml_combine_effects(struct ff_effect *effect,
+			       struct ml_effect_state *state,
+			       int gain)
+{
+	struct ff_effect *new = state->effect;
+	unsigned int strong, weak, i;
+	int x, y;
+	s16 level;
+
+	switch (new->type) {
+	case FF_CONSTANT:
+		i = new->direction * 360 / 0xffff;
+		level = fixp_new16(apply_envelope(state,
+					new->u.constant.level,
+					&new->u.constant.envelope));
+		x = fixp_mult(fixp_sin16(i), level) * gain / 0xffff;
+		y = fixp_mult(-fixp_cos16(i), level) * gain / 0xffff;
+		/*
+		 * here we abuse ff_ramp to hold x and y of constant force
+		 * If in future any driver wants something else than x and y
+		 * in s8, this should be changed to something more generic
+		 */
+		effect->u.ramp.start_level =
+			clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f);
+		effect->u.ramp.end_level =
+			clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f);
+		break;
+
+	case FF_RUMBLE:
+		strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff;
+		weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff;
+
+		if (effect->u.rumble.strong_magnitude + strong)
+			effect->direction = ml_calculate_direction(
+				effect->direction,
+				effect->u.rumble.strong_magnitude,
+				new->direction, strong);
+		else if (effect->u.rumble.weak_magnitude + weak)
+			effect->direction = ml_calculate_direction(
+				effect->direction,
+				effect->u.rumble.weak_magnitude,
+				new->direction, weak);
+		else
+			effect->direction = 0;
+		effect->u.rumble.strong_magnitude =
+			min(strong + effect->u.rumble.strong_magnitude,
+			    0xffffU);
+		effect->u.rumble.weak_magnitude =
+			min(weak + effect->u.rumble.weak_magnitude, 0xffffU);
+		break;
+
+	case FF_PERIODIC:
+		i = apply_envelope(state, abs(new->u.periodic.magnitude),
+				   &new->u.periodic.envelope);
+
+		/* here we also scale it 0x7fff => 0xffff */
+		i = i * gain / 0x7fff;
+
+		if (effect->u.rumble.strong_magnitude + i)
+			effect->direction = ml_calculate_direction(
+				effect->direction,
+				effect->u.rumble.strong_magnitude,
+				new->direction, i);
+		else
+			effect->direction = 0;
+		effect->u.rumble.strong_magnitude =
+			min(i + effect->u.rumble.strong_magnitude, 0xffffU);
+		effect->u.rumble.weak_magnitude =
+			min(i + effect->u.rumble.weak_magnitude, 0xffffU);
+		break;
+
+	default:
+		pr_err("invalid type in ml_combine_effects()\n");
+		break;
+	}
+
+}
+
+
+/*
+ * Because memoryless devices have only one effect per effect type active
+ * at one time we have to combine multiple effects into one
+ */
+static int ml_get_combo_effect(struct ml_device *ml,
+			       unsigned long *effect_handled,
+			       struct ff_effect *combo_effect)
+{
+	struct ff_effect *effect;
+	struct ml_effect_state *state;
+	int effect_type;
+	int i;
+
+	memset(combo_effect, 0, sizeof(struct ff_effect));
+
+	for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
+		if (__test_and_set_bit(i, effect_handled))
+			continue;
+
+		state = &ml->states[i];
+		effect = state->effect;
+
+		if (!test_bit(FF_EFFECT_STARTED, &state->flags))
+			continue;
+
+		if (time_before(jiffies, state->play_at))
+			continue;
+
+		/*
+		 * here we have started effects that are either
+		 * currently playing (and may need be aborted)
+		 * or need to start playing.
+		 */
+		effect_type = get_compatible_type(ml->dev->ff, effect->type);
+		if (combo_effect->type != effect_type) {
+			if (combo_effect->type != 0) {
+				__clear_bit(i, effect_handled);
+				continue;
+			}
+			combo_effect->type = effect_type;
+		}
+
+		if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) {
+			__clear_bit(FF_EFFECT_PLAYING, &state->flags);
+			__clear_bit(FF_EFFECT_STARTED, &state->flags);
+		} else if (effect->replay.length &&
+			   time_after_eq(jiffies, state->stop_at)) {
+
+			__clear_bit(FF_EFFECT_PLAYING, &state->flags);
+
+			if (--state->count <= 0) {
+				__clear_bit(FF_EFFECT_STARTED, &state->flags);
+			} else {
+				state->play_at = jiffies +
+					msecs_to_jiffies(effect->replay.delay);
+				state->stop_at = state->play_at +
+					msecs_to_jiffies(effect->replay.length);
+			}
+		} else {
+			__set_bit(FF_EFFECT_PLAYING, &state->flags);
+			state->adj_at = jiffies;
+			ml_combine_effects(combo_effect, state, ml->gain);
+		}
+	}
+
+	return combo_effect->type != 0;
+}
+
+static void ml_play_effects(struct ml_device *ml)
+{
+	struct ff_effect effect;
+	DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS);
+
+	memset(handled_bm, 0, sizeof(handled_bm));
+
+	while (ml_get_combo_effect(ml, handled_bm, &effect))
+		ml->play_effect(ml->dev, ml->private, &effect);
+
+	ml_schedule_timer(ml);
+}
+
+static void ml_effect_timer(struct timer_list *t)
+{
+	struct ml_device *ml = timer_container_of(ml, t, timer);
+	struct input_dev *dev = ml->dev;
+
+	pr_debug("timer: updating effects\n");
+
+	guard(spinlock_irqsave)(&dev->event_lock);
+	ml_play_effects(ml);
+}
+
+/*
+ * 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;
+
+	ml->gain = gain;
+
+	for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
+		__clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags);
+
+	ml_play_effects(ml);
+}
+
+/*
+ * 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];
+
+	if (value > 0) {
+		pr_debug("initiated play\n");
+
+		__set_bit(FF_EFFECT_STARTED, &state->flags);
+		state->count = value;
+		state->play_at = jiffies +
+				 msecs_to_jiffies(state->effect->replay.delay);
+		state->stop_at = state->play_at +
+				 msecs_to_jiffies(state->effect->replay.length);
+		state->adj_at = state->play_at;
+
+	} else {
+		pr_debug("initiated stop\n");
+
+		if (test_bit(FF_EFFECT_PLAYING, &state->flags))
+			__set_bit(FF_EFFECT_ABORTING, &state->flags);
+		else
+			__clear_bit(FF_EFFECT_STARTED, &state->flags);
+	}
+
+	ml_play_effects(ml);
+
+	return 0;
+}
+
+static int ml_ff_upload(struct input_dev *dev,
+			struct ff_effect *effect, struct ff_effect *old)
+{
+	struct ml_device *ml = dev->ff->private;
+	struct ml_effect_state *state = &ml->states[effect->id];
+
+	guard(spinlock_irq)(&dev->event_lock);
+
+	if (test_bit(FF_EFFECT_STARTED, &state->flags)) {
+		__clear_bit(FF_EFFECT_PLAYING, &state->flags);
+		state->play_at = jiffies +
+				 msecs_to_jiffies(state->effect->replay.delay);
+		state->stop_at = state->play_at +
+				 msecs_to_jiffies(state->effect->replay.length);
+		state->adj_at = state->play_at;
+		ml_schedule_timer(ml);
+	}
+
+	return 0;
+}
+
+static void ml_ff_destroy(struct ff_device *ff)
+{
+	struct ml_device *ml = ff->private;
+
+	/*
+	 * The timer is normally shut down in ml_ff_stop() when the device
+	 * is unregistered. However, we still shut it down here as a safety
+	 * net and for cases where the device was never registered (e.g.
+	 * error paths during probe).
+	 */
+	timer_shutdown_sync(&ml->timer);
+
+	kfree(ml->private);
+}
+
+static void ml_ff_stop(struct ff_device *ff)
+{
+	struct ml_device *ml = ff->private;
+
+	/*
+	 * Even though we stop all playing effects when tearing down an
+	 * input device (by the way of evdev calling input_flush_device()
+	 * that calls into input_ff_flush() that stops and erases all
+	 * effects), we do not actually shutdown the timer, and therefore
+	 * we should do it here to prevent it firing after the input
+	 * device is unregistered and its associated resources are freed.
+	 */
+	timer_shutdown_sync(&ml->timer);
+}
+
+/**
+ * input_ff_create_memless() - create memoryless force-feedback device
+ * @dev: input device supporting force-feedback
+ * @data: driver-specific data to be passed into @play_effect
+ * @play_effect: driver-specific method for playing FF effect
+ */
+int input_ff_create_memless(struct input_dev *dev, void *data,
+		int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
+{
+	struct ff_device *ff;
+	int error;
+	int i;
+
+	struct ml_device *ml __free(kfree) = kzalloc_obj(*ml);
+	if (!ml)
+		return -ENOMEM;
+
+	ml->dev = dev;
+	ml->private = data;
+	ml->play_effect = play_effect;
+	ml->gain = 0xffff;
+	timer_setup(&ml->timer, ml_effect_timer, 0);
+
+	set_bit(FF_GAIN, dev->ffbit);
+
+	error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
+	if (error)
+		return error;
+
+	ff = dev->ff;
+	ff->upload = ml_ff_upload;
+	ff->playback = ml_ff_playback;
+	ff->set_gain = ml_ff_set_gain;
+	ff->destroy = ml_ff_destroy;
+	ff->stop = ml_ff_stop;
+
+	/* we can emulate periodic effects with RUMBLE */
+	if (test_bit(FF_RUMBLE, ff->ffbit)) {
+		set_bit(FF_PERIODIC, dev->ffbit);
+		set_bit(FF_SINE, dev->ffbit);
+		set_bit(FF_TRIANGLE, dev->ffbit);
+		set_bit(FF_SQUARE, dev->ffbit);
+	}
+
+	for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
+		ml->states[i].effect = &ff->effects[i];
+
+	ff->private = no_free_ptr(ml);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(input_ff_create_memless);