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Commit ccf5b801 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: make intf.pm_usage an atomic_t 



This patch (as1260) changes the pm_usage_cnt field in struct
usb_interface from an int to an atomic_t.  This is so that drivers can
invoke the usb_autopm_get_interface_async() and
usb_autopm_put_interface_async() routines without locking and without
fear of corrupting the pm_usage_cnt value.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 7cbe5dca

drivers/usb/core/driver.c

+22 −16
Original line number Diff line number Diff line
@@ -235,7 +235,7 @@ static int usb_probe_interface(struct device *dev) 
		/* The interface should always appear to be in use

		 * unless the driver suports autosuspend.

		 */

		intf->pm_usage_cnt = !(driver->supports_autosuspend);

		atomic_set(&intf->pm_usage_cnt, !driver->supports_autosuspend);



		/* Carry out a deferred switch to altsetting 0 */

		if (intf->needs_altsetting0) {
@@ -347,7 +347,7 @@ int usb_driver_claim_interface(struct usb_driver *driver, 
	usb_pm_lock(udev);

	iface->condition = USB_INTERFACE_BOUND;

	mark_active(iface);

	iface->pm_usage_cnt = !(driver->supports_autosuspend);

	atomic_set(&iface->pm_usage_cnt, !driver->supports_autosuspend);

	usb_pm_unlock(udev);



	/* if interface was already added, bind now; else let
@@ -1068,7 +1068,7 @@ static int autosuspend_check(struct usb_device *udev, int reschedule) 
			intf = udev->actconfig->interface[i];

			if (!is_active(intf))

				continue;

			if (intf->pm_usage_cnt > 0)

			if (atomic_read(&intf->pm_usage_cnt) > 0)

				return -EBUSY;

			if (intf->needs_remote_wakeup &&

					!udev->do_remote_wakeup) {
@@ -1464,17 +1464,19 @@ static int usb_autopm_do_interface(struct usb_interface *intf, 
		status = -ENODEV;

	else {

		udev->auto_pm = 1;

		intf->pm_usage_cnt += inc_usage_cnt;

		atomic_add(inc_usage_cnt, &intf->pm_usage_cnt);

		udev->last_busy = jiffies;

		if (inc_usage_cnt >= 0 && intf->pm_usage_cnt > 0) {

		if (inc_usage_cnt >= 0 &&

				atomic_read(&intf->pm_usage_cnt) > 0) {

			if (udev->state == USB_STATE_SUSPENDED)

				status = usb_resume_both(udev,

						PMSG_AUTO_RESUME);

			if (status != 0)

				intf->pm_usage_cnt -= inc_usage_cnt;

				atomic_sub(inc_usage_cnt, &intf->pm_usage_cnt);

			else

				udev->last_busy = jiffies;

		} else if (inc_usage_cnt <= 0 && intf->pm_usage_cnt <= 0) {

		} else if (inc_usage_cnt <= 0 &&

				atomic_read(&intf->pm_usage_cnt) <= 0) {

			status = usb_suspend_both(udev, PMSG_AUTO_SUSPEND);

		}

	}
@@ -1519,7 +1521,7 @@ void usb_autopm_put_interface(struct usb_interface *intf) 


	status = usb_autopm_do_interface(intf, -1);

	dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",

			__func__, status, intf->pm_usage_cnt);

			__func__, status, atomic_read(&intf->pm_usage_cnt));

}

EXPORT_SYMBOL_GPL(usb_autopm_put_interface);
@@ -1547,10 +1549,10 @@ void usb_autopm_put_interface_async(struct usb_interface *intf) 
		status = -ENODEV;

	} else {

		udev->last_busy = jiffies;

		--intf->pm_usage_cnt;

		atomic_dec(&intf->pm_usage_cnt);

		if (udev->autosuspend_disabled || udev->autosuspend_delay < 0)

			status = -EPERM;

		else if (intf->pm_usage_cnt <= 0 &&

		else if (atomic_read(&intf->pm_usage_cnt) <= 0 &&

				!timer_pending(&udev->autosuspend.timer)) {

			queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,

					round_jiffies_up_relative(
@@ -1558,7 +1560,7 @@ void usb_autopm_put_interface_async(struct usb_interface *intf) 
		}

	}

	dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",

			__func__, status, intf->pm_usage_cnt);

			__func__, status, atomic_read(&intf->pm_usage_cnt));

}

EXPORT_SYMBOL_GPL(usb_autopm_put_interface_async);
@@ -1602,7 +1604,7 @@ int usb_autopm_get_interface(struct usb_interface *intf) 


	status = usb_autopm_do_interface(intf, 1);

	dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",

			__func__, status, intf->pm_usage_cnt);

			__func__, status, atomic_read(&intf->pm_usage_cnt));

	return status;

}

EXPORT_SYMBOL_GPL(usb_autopm_get_interface);
@@ -1630,10 +1632,14 @@ int usb_autopm_get_interface_async(struct usb_interface *intf) 
		status = -ENODEV;

	else if (udev->autoresume_disabled)

		status = -EPERM;

	else if (++intf->pm_usage_cnt > 0 && udev->state == USB_STATE_SUSPENDED)

	else {

		atomic_inc(&intf->pm_usage_cnt);

		if (atomic_read(&intf->pm_usage_cnt) > 0 &&

				udev->state == USB_STATE_SUSPENDED)

			queue_work(ksuspend_usb_wq, &udev->autoresume);

	}

	dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",

			__func__, status, intf->pm_usage_cnt);

			__func__, status, atomic_read(&intf->pm_usage_cnt));

	return status;

}

EXPORT_SYMBOL_GPL(usb_autopm_get_interface_async);
@@ -1655,7 +1661,7 @@ int usb_autopm_set_interface(struct usb_interface *intf) 


	status = usb_autopm_do_interface(intf, 0);

	dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",

			__func__, status, intf->pm_usage_cnt);

			__func__, status, atomic_read(&intf->pm_usage_cnt));

	return status;

}

EXPORT_SYMBOL_GPL(usb_autopm_set_interface);

drivers/usb/core/hub.c

+3 −2
Original line number Diff line number Diff line
@@ -373,7 +373,7 @@ static void kick_khubd(struct usb_hub *hub) 
	unsigned long	flags;



	/* Suppress autosuspend until khubd runs */

	to_usb_interface(hub->intfdev)->pm_usage_cnt = 1;

	atomic_set(&to_usb_interface(hub->intfdev)->pm_usage_cnt, 1);



	spin_lock_irqsave(&hub_event_lock, flags);

	if (!hub->disconnected && list_empty(&hub->event_list)) {
@@ -678,7 +678,8 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type) 
					msecs_to_jiffies(delay));



			/* Suppress autosuspend until init is done */

			to_usb_interface(hub->intfdev)->pm_usage_cnt = 1;

			atomic_set(&to_usb_interface(hub->intfdev)->

					pm_usage_cnt, 1);

			return;		/* Continues at init2: below */

		} else {

			hub_power_on(hub, true);

include/linux/usb.h

+3 −3
Original line number Diff line number Diff line
@@ -195,7 +195,7 @@ struct usb_interface { 


	struct device dev;		/* interface specific device info */

	struct device *usb_dev;

	int pm_usage_cnt;		/* usage counter for autosuspend */

	atomic_t pm_usage_cnt;		/* usage counter for autosuspend */

	struct work_struct reset_ws;	/* for resets in atomic context */

};

#define	to_usb_interface(d) container_of(d, struct usb_interface, dev)
@@ -551,13 +551,13 @@ extern void usb_autopm_put_interface_async(struct usb_interface *intf); 


static inline void usb_autopm_enable(struct usb_interface *intf)

{

	intf->pm_usage_cnt = 0;

	atomic_set(&intf->pm_usage_cnt, 0);

	usb_autopm_set_interface(intf);

}



static inline void usb_autopm_disable(struct usb_interface *intf)

{

	intf->pm_usage_cnt = 1;

	atomic_set(&intf->pm_usage_cnt, 1);

	usb_autopm_set_interface(intf);

}