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Subject[patch 02/24] uinput: use completions
Input: uinput - use completions instead of events and manual
wakeups in force feedback code.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---
drivers/input/misc/uinput.c | 81 +++++++++++++++++++++++---------------------
include/linux/uinput.h | 5 +-
2 files changed, 45 insertions(+), 41 deletions(-)
Index: work/drivers/input/misc/uinput.c
===================================================================
--- work.orig/drivers/input/misc/uinput.c
+++ work/drivers/input/misc/uinput.c
@@ -53,24 +53,23 @@ static int uinput_dev_event(struct input
return 0;
}

-static int uinput_request_alloc_id(struct input_dev *dev, struct uinput_request *request)
+static int uinput_request_alloc_id(struct uinput_device *udev, struct uinput_request *request)
{
/* Atomically allocate an ID for the given request. Returns 0 on success. */
- struct uinput_device *udev = dev->private;
int id;
int err = -1;

- down(&udev->requests_sem);
+ spin_lock(&udev->requests_lock);

for (id = 0; id < UINPUT_NUM_REQUESTS; id++)
if (!udev->requests[id]) {
- udev->requests[id] = request;
request->id = id;
+ udev->requests[id] = request;
err = 0;
break;
}

- up(&udev->requests_sem);
+ spin_unlock(&udev->requests_lock);
return err;
}

@@ -79,70 +78,78 @@ static struct uinput_request* uinput_req
/* Find an input request, by ID. Returns NULL if the ID isn't valid. */
if (id >= UINPUT_NUM_REQUESTS || id < 0)
return NULL;
- if (udev->requests[id]->completed)
- return NULL;
return udev->requests[id];
}

-static void uinput_request_init(struct input_dev *dev, struct uinput_request *request, int code)
+static inline int uinput_request_reserve_slot(struct uinput_device *udev, struct uinput_request *request)
{
- struct uinput_device *udev = dev->private;
+ /* Allocate slot. If none are available right away, wait. */
+ return wait_event_interruptible(udev->requests_waitq,
+ !uinput_request_alloc_id(udev, request));
+}

- memset(request, 0, sizeof(struct uinput_request));
- request->code = code;
- init_waitqueue_head(&request->waitq);
+static void uinput_request_done(struct uinput_device *udev, struct uinput_request *request)
+{
+ complete(&request->done);

- /* Allocate an ID. If none are available right away, wait. */
- request->retval = wait_event_interruptible(udev->requests_waitq,
- !uinput_request_alloc_id(dev, request));
+ /* Mark slot as available */
+ udev->requests[request->id] = NULL;
+ wake_up_interruptible(&udev->requests_waitq);
}

-static void uinput_request_submit(struct input_dev *dev, struct uinput_request *request)
+static int uinput_request_submit(struct input_dev *dev, struct uinput_request *request)
{
- struct uinput_device *udev = dev->private;
int retval;

/* Tell our userspace app about this new request by queueing an input event */
uinput_dev_event(dev, EV_UINPUT, request->code, request->id);

/* Wait for the request to complete */
- retval = wait_event_interruptible(request->waitq, request->completed);
- if (retval)
- request->retval = retval;
+ retval = wait_for_completion_interruptible(&request->done);
+ if (!retval)
+ retval = request->retval;

- /* Release this request's ID, let others know it's available */
- udev->requests[request->id] = NULL;
- wake_up_interruptible(&udev->requests_waitq);
+ return retval;
}

static int uinput_dev_upload_effect(struct input_dev *dev, struct ff_effect *effect)
{
struct uinput_request request;
+ int retval;

if (!test_bit(EV_FF, dev->evbit))
return -ENOSYS;

- uinput_request_init(dev, &request, UI_FF_UPLOAD);
- if (request.retval)
- return request.retval;
+ request.id = -1;
+ init_completion(&request.done);
+ request.code = UI_FF_UPLOAD;
request.u.effect = effect;
- uinput_request_submit(dev, &request);
- return request.retval;
+
+ retval = uinput_request_reserve_slot(dev->private, &request);
+ if (!retval)
+ retval = uinput_request_submit(dev, &request);
+
+ return retval;
}

static int uinput_dev_erase_effect(struct input_dev *dev, int effect_id)
{
struct uinput_request request;
+ int retval;

if (!test_bit(EV_FF, dev->evbit))
return -ENOSYS;

- uinput_request_init(dev, &request, UI_FF_ERASE);
- if (request.retval)
- return request.retval;
+ request.id = -1;
+ init_completion(&request.done);
+ request.code = UI_FF_ERASE;
request.u.effect_id = effect_id;
- uinput_request_submit(dev, &request);
- return request.retval;
+
+ retval = uinput_request_reserve_slot(dev->private, &request);
+ if (!retval)
+ retval = uinput_request_submit(dev, &request);
+
+ return retval;
}

static int uinput_create_device(struct uinput_device *udev)
@@ -189,7 +196,7 @@ static int uinput_open(struct inode *ino
if (!newdev)
goto error;
memset(newdev, 0, sizeof(struct uinput_device));
- init_MUTEX(&newdev->requests_sem);
+ spin_lock_init(&newdev->requests_lock);
init_waitqueue_head(&newdev->requests_waitq);

newinput = kmalloc(sizeof(struct input_dev), GFP_KERNEL);
@@ -551,8 +558,7 @@ static int uinput_ioctl(struct inode *in
}
req->retval = ff_up.retval;
memcpy(req->u.effect, &ff_up.effect, sizeof(struct ff_effect));
- req->completed = 1;
- wake_up_interruptible(&req->waitq);
+ uinput_request_done(udev, req);
break;

case UI_END_FF_ERASE:
@@ -566,8 +572,7 @@ static int uinput_ioctl(struct inode *in
break;
}
req->retval = ff_erase.retval;
- req->completed = 1;
- wake_up_interruptible(&req->waitq);
+ uinput_request_done(udev, req);
break;

default:
Index: work/include/linux/uinput.h
===================================================================
--- work.orig/include/linux/uinput.h
+++ work/include/linux/uinput.h
@@ -42,8 +42,7 @@ struct uinput_request {
int code; /* UI_FF_UPLOAD, UI_FF_ERASE */

int retval;
- wait_queue_head_t waitq;
- int completed;
+ struct completion done;

union {
int effect_id;
@@ -62,7 +61,7 @@ struct uinput_device {

struct uinput_request *requests[UINPUT_NUM_REQUESTS];
wait_queue_head_t requests_waitq;
- struct semaphore requests_sem;
+ spinlock_t requests_lock;
};
#endif /* __KERNEL__ */

-
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