[RFT]patch to remove kernel thread for runtime pm from usbhid

[Oliver Neukum <oneukum@suse.de>]

Hi,

this patch saves a kernel thread. It works with my mouse. Please test.

	Regards
		Oliver

>From 89cb25b186e336c04f74165f08bca6c934ebdfad Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oliver@neukum.org>
Date: Tue, 12 Oct 2010 09:28:11 +0200
Subject: [PATCH] Input: usbhid: convert runtime pm to async API

This patch removes the dedicated work queue and thus the kernel thread
used to wake up USB HID devices. It is replaced with the use of
the async API which didn't exist when runtime pm was introduced to
usbhid.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
---
 Makefile                      |    2 +-
 drivers/hid/usbhid/hid-core.c |   57 +++++++++++++---------------------------
 drivers/hid/usbhid/usbhid.h   |    1 -
 drivers/usb/core/usb.h        |   13 +++++++++
 4 files changed, 33 insertions(+), 40 deletions(-)

diff --git a/Makefile b/Makefile
index 77b5c6e..f610e8c 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 VERSION = 2
 PATCHLEVEL = 6
 SUBLEVEL = 36
-EXTRAVERSION = -rc7
+EXTRAVERSION = -rc7hid
 NAME = Sheep on Meth
 
 # *DOCUMENTATION*
diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index 599041a..8e7f785 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -67,7 +67,6 @@ MODULE_PARM_DESC(quirks, "Add/modify USB HID quirks by specifying "
  * Input submission and I/O error handler.
  */
 static DEFINE_MUTEX(hid_open_mut);
-static struct workqueue_struct *resumption_waker;
 
 static void hid_io_error(struct hid_device *hid);
 static int hid_submit_out(struct hid_device *hid);
@@ -300,10 +299,19 @@ static int hid_submit_out(struct hid_device *hid)
 	struct hid_report *report;
 	char *raw_report;
 	struct usbhid_device *usbhid = hid->driver_data;
+	int r;
 
 	report = usbhid->out[usbhid->outtail].report;
 	raw_report = usbhid->out[usbhid->outtail].raw_report;
 
+	r = usb_autopm_get_interface_async(usbhid->intf);
+	if (r < 0)
+		return -1;
+
+	/*
+	 * if the device hasn't been woken, we leave the output
+	 * to resume()
+	 */
 	if (!test_bit(HID_REPORTED_IDLE, &usbhid->iofl)) {
 		usbhid->urbout->transfer_buffer_length = ((report->size - 1) >> 3) + 1 + (report->id > 0);
 		usbhid->urbout->dev = hid_to_usb_dev(hid);
@@ -314,16 +322,10 @@ static int hid_submit_out(struct hid_device *hid)
 
 		if (usb_submit_urb(usbhid->urbout, GFP_ATOMIC)) {
 			err_hid("usb_submit_urb(out) failed");
+			usb_autopm_put_interface_async(usbhid->intf);
 			return -1;
 		}
 		usbhid->last_out = jiffies;
-	} else {
-		/*
-		 * queue work to wake up the device.
-		 * as the work queue is freezeable, this is safe
-		 * with respect to STD and STR
-		 */
-		queue_work(resumption_waker, &usbhid->restart_work);
 	}
 
 	return 0;
@@ -334,13 +336,16 @@ static int hid_submit_ctrl(struct hid_device *hid)
 	struct hid_report *report;
 	unsigned char dir;
 	char *raw_report;
-	int len;
+	int len, r;
 	struct usbhid_device *usbhid = hid->driver_data;
 
 	report = usbhid->ctrl[usbhid->ctrltail].report;
 	raw_report = usbhid->ctrl[usbhid->ctrltail].raw_report;
 	dir = usbhid->ctrl[usbhid->ctrltail].dir;
 
+	r = usb_autopm_get_interface_async(usbhid->intf);
+	if (r < 0)
+		return -1;
 	if (!test_bit(HID_REPORTED_IDLE, &usbhid->iofl)) {
 		len = ((report->size - 1) >> 3) + 1 + (report->id > 0);
 		if (dir == USB_DIR_OUT) {
@@ -375,17 +380,11 @@ static int hid_submit_ctrl(struct hid_device *hid)
 			usbhid->cr->wValue, usbhid->cr->wIndex, usbhid->cr->wLength);
 
 		if (usb_submit_urb(usbhid->urbctrl, GFP_ATOMIC)) {
+			usb_autopm_put_interface_async(usbhid->intf);
 			err_hid("usb_submit_urb(ctrl) failed");
 			return -1;
 		}
 		usbhid->last_ctrl = jiffies;
-	} else {
-		/*
-		 * queue work to wake up the device.
-		 * as the work queue is freezeable, this is safe
-		 * with respect to STD and STR
-		 */
-		queue_work(resumption_waker, &usbhid->restart_work);
 	}
 
 	return 0;
@@ -435,6 +434,7 @@ static void hid_irq_out(struct urb *urb)
 
 	clear_bit(HID_OUT_RUNNING, &usbhid->iofl);
 	spin_unlock_irqrestore(&usbhid->lock, flags);
+	usb_autopm_put_interface_async(usbhid->intf);
 	wake_up(&usbhid->wait);
 }
 
@@ -481,11 +481,13 @@ static void hid_ctrl(struct urb *urb)
 			wake_up(&usbhid->wait);
 		}
 		spin_unlock(&usbhid->lock);
+		usb_autopm_put_interface_async(usbhid->intf);
 		return;
 	}
 
 	clear_bit(HID_CTRL_RUNNING, &usbhid->iofl);
 	spin_unlock(&usbhid->lock);
+	usb_autopm_put_interface_async(usbhid->intf);
 	wake_up(&usbhid->wait);
 }
 
@@ -656,7 +658,7 @@ int usbhid_open(struct hid_device *hid)
 	mutex_lock(&hid_open_mut);
 	if (!hid->open++) {
 		res = usb_autopm_get_interface(usbhid->intf);
-		/* the device must be awake to reliable request remote wakeup */
+		/* the device must be awake to reliably request remote wakeup */
 		if (res < 0) {
 			hid->open--;
 			mutex_unlock(&hid_open_mut);
@@ -856,18 +858,6 @@ static void usbhid_restart_queues(struct usbhid_device *usbhid)
 	usbhid_restart_ctrl_queue(usbhid);
 }
 
-static void __usbhid_restart_queues(struct work_struct *work)
-{
-	struct usbhid_device *usbhid =
-		container_of(work, struct usbhid_device, restart_work);
-	int r;
-
-	r = usb_autopm_get_interface(usbhid->intf);
-	if (r < 0)
-		return;
-	usb_autopm_put_interface(usbhid->intf);
-}
-
 static void hid_free_buffers(struct usb_device *dev, struct hid_device *hid)
 {
 	struct usbhid_device *usbhid = hid->driver_data;
@@ -1205,7 +1195,6 @@ static int usbhid_probe(struct usb_interface *intf, const struct usb_device_id *
 
 	init_waitqueue_head(&usbhid->wait);
 	INIT_WORK(&usbhid->reset_work, hid_reset);
-	INIT_WORK(&usbhid->restart_work, __usbhid_restart_queues);
 	setup_timer(&usbhid->io_retry, hid_retry_timeout, (unsigned long) hid);
 	spin_lock_init(&usbhid->lock);
 
@@ -1240,7 +1229,6 @@ static void usbhid_disconnect(struct usb_interface *intf)
 static void hid_cancel_delayed_stuff(struct usbhid_device *usbhid)
 {
 	del_timer_sync(&usbhid->io_retry);
-	cancel_work_sync(&usbhid->restart_work);
 	cancel_work_sync(&usbhid->reset_work);
 }
 
@@ -1261,7 +1249,6 @@ static int hid_pre_reset(struct usb_interface *intf)
 	spin_lock_irq(&usbhid->lock);
 	set_bit(HID_RESET_PENDING, &usbhid->iofl);
 	spin_unlock_irq(&usbhid->lock);
-	cancel_work_sync(&usbhid->restart_work);
 	hid_cease_io(usbhid);
 
 	return 0;
@@ -1460,9 +1447,6 @@ static int __init hid_init(void)
 {
 	int retval = -ENOMEM;
 
-	resumption_waker = create_freezeable_workqueue("usbhid_resumer");
-	if (!resumption_waker)
-		goto no_queue;
 	retval = hid_register_driver(&hid_usb_driver);
 	if (retval)
 		goto hid_register_fail;
@@ -1485,8 +1469,6 @@ hiddev_init_fail:
 usbhid_quirks_init_fail:
 	hid_unregister_driver(&hid_usb_driver);
 hid_register_fail:
-	destroy_workqueue(resumption_waker);
-no_queue:
 	return retval;
 }
 
@@ -1496,7 +1478,6 @@ static void __exit hid_exit(void)
 	hiddev_exit();
 	usbhid_quirks_exit();
 	hid_unregister_driver(&hid_usb_driver);
-	destroy_workqueue(resumption_waker);
 }
 
 module_init(hid_init);
diff --git a/drivers/hid/usbhid/usbhid.h b/drivers/hid/usbhid/usbhid.h
index 89d2e84..1673cac 100644
--- a/drivers/hid/usbhid/usbhid.h
+++ b/drivers/hid/usbhid/usbhid.h
@@ -95,7 +95,6 @@ struct usbhid_device {
 	unsigned long stop_retry;                                       /* Time to give up, in jiffies */
 	unsigned int retry_delay;                                       /* Delay length in ms */
 	struct work_struct reset_work;                                  /* Task context for resets */
-	struct work_struct restart_work;				/* waking up for output to be done in a task */
 	wait_queue_head_t wait;						/* For sleeping */
 	int ledcount;							/* counting the number of active leds */
 };
diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index cd88220..fbb988a 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -124,6 +124,19 @@ static inline int is_usb_device_driver(struct device_driver *drv)
 			for_devices;
 }
 
+/* translate USB error codes to codes user space understands */
+static inline int usb_translate_errors(int error_code)
+{
+	switch (error_code) {
+	case 0:
+	case -ENOMEM:
+	case -ENODEV:
+		return error_code;
+	default:
+		return -EIO;
+	}
+}
+
 
 /* for labeling diagnostics */
 extern const char *usbcore_name;
-- 
1.7.1