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Commit fde5be35 authored by Jiri Slaby's avatar Jiri Slaby Committed by Jiri Kosina
Browse files

HID: remove setup mutex, fix possible deadlock 



It causes recursive locking warning and is unneeded after
introduction of STARTED flag.

* Resume vs. stop is effectively solved by DISCONNECT flag.
* No problem in suspend vs. start -- urb is submitted even after open
  which is possible after connect which is called after start.
* Resume vs. start solved by STARTED flag.
* Suspend vs. stop -- no problem in killing urb and timer twice.

Reported-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarJiri Slaby <jirislaby@gmail.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 578f3a35

drivers/hid/usbhid/hid-core.c

+2 −16
Original line number Diff line number Diff line
@@ -796,7 +796,6 @@ static int usbhid_start(struct hid_device *hid) 
	if (insize > HID_MAX_BUFFER_SIZE)

		insize = HID_MAX_BUFFER_SIZE;



	mutex_lock(&usbhid->setup);

	if (hid_alloc_buffers(dev, hid)) {

		ret = -ENOMEM;

		goto fail;
@@ -876,7 +875,6 @@ static int usbhid_start(struct hid_device *hid) 
	hid_dump_device(hid);



	set_bit(HID_STARTED, &usbhid->iofl);

	mutex_unlock(&usbhid->setup);



	return 0;
@@ -888,7 +886,6 @@ static int usbhid_start(struct hid_device *hid) 
	usbhid->urbout = NULL;

	usbhid->urbctrl = NULL;

	hid_free_buffers(dev, hid);

	mutex_unlock(&usbhid->setup);

	return ret;

}
@@ -899,7 +896,6 @@ static void usbhid_stop(struct hid_device *hid) 
	if (WARN_ON(!usbhid))

		return;



	mutex_lock(&usbhid->setup);

	clear_bit(HID_STARTED, &usbhid->iofl);

	spin_lock_irq(&usbhid->inlock);	/* Sync with error handler */

	set_bit(HID_DISCONNECTED, &usbhid->iofl);
@@ -928,7 +924,6 @@ static void usbhid_stop(struct hid_device *hid) 
	usbhid->urbout = NULL;



	hid_free_buffers(hid_to_usb_dev(hid), hid);

	mutex_unlock(&usbhid->setup);

}



static struct hid_ll_driver usb_hid_driver = {
@@ -1016,7 +1011,6 @@ static int hid_probe(struct usb_interface *intf, const struct usb_device_id *id) 


	hid->driver_data = usbhid;

	usbhid->hid = hid;

	mutex_init(&usbhid->setup); /* needed on suspend/resume */



	ret = hid_add_device(hid);

	if (ret) {
@@ -1051,18 +1045,14 @@ static int hid_suspend(struct usb_interface *intf, pm_message_t message) 
	struct hid_device *hid = usb_get_intfdata (intf);

	struct usbhid_device *usbhid = hid->driver_data;



	mutex_lock(&usbhid->setup);

	if (!test_bit(HID_STARTED, &usbhid->iofl)) {

		mutex_unlock(&usbhid->setup);

	if (!test_bit(HID_STARTED, &usbhid->iofl))

		return 0;

	}



	spin_lock_irq(&usbhid->inlock);	/* Sync with error handler */

	set_bit(HID_SUSPENDED, &usbhid->iofl);

	spin_unlock_irq(&usbhid->inlock);

	del_timer_sync(&usbhid->io_retry);

	usb_kill_urb(usbhid->urbin);

	mutex_unlock(&usbhid->setup);

	dev_dbg(&intf->dev, "suspend\n");

	return 0;

}
@@ -1073,16 +1063,12 @@ static int hid_resume(struct usb_interface *intf) 
	struct usbhid_device *usbhid = hid->driver_data;

	int status;



	mutex_lock(&usbhid->setup);

	if (!test_bit(HID_STARTED, &usbhid->iofl)) {

		mutex_unlock(&usbhid->setup);

	if (!test_bit(HID_STARTED, &usbhid->iofl))

		return 0;

	}



	clear_bit(HID_SUSPENDED, &usbhid->iofl);

	usbhid->retry_delay = 0;

	status = hid_start_in(hid);

	mutex_unlock(&usbhid->setup);

	dev_dbg(&intf->dev, "resume status %d\n", status);

	return status;

}

drivers/hid/usbhid/usbhid.h

+0 −1
Original line number Diff line number Diff line
@@ -74,7 +74,6 @@ struct usbhid_device { 
	dma_addr_t outbuf_dma;                                          /* Output buffer dma */

	spinlock_t outlock;                                             /* Output fifo spinlock */



	struct mutex setup;

	unsigned long iofl;                                             /* I/O flags (CTRL_RUNNING, OUT_RUNNING) */

	struct timer_list io_retry;                                     /* Retry timer */

	unsigned long stop_retry;                                       /* Time to give up, in jiffies */