HID: usbkbd: synchronize LED URB submission
usb_kbd_event() and usb_kbd_led() can be called concurrently, but they are not synchronized. They both readwrite kbd->leds, and usb_kbd_event() originally just checked the URB status field, while urb.h states that "It [status field] should not be examined before the URB is returned to the completion handler." To fix this unsynchronized behavior, this patch introduces a boolean representing whether the URB is submitted, and a spinlock. Signed-off-by: Willem Penninckx <willem.penninckx@cs.kuleuven.be> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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@ -64,6 +64,32 @@ static const unsigned char usb_kbd_keycode[256] = {
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150,158,159,128,136,177,178,176,142,152,173,140
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};
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/**
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* struct usb_kbd - state of each attached keyboard
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* @dev: input device associated with this keyboard
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* @usbdev: usb device associated with this keyboard
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* @old: data received in the past from the @irq URB representing which
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* keys were pressed. By comparing with the current list of keys
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* that are pressed, we are able to see key releases.
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* @irq: URB for receiving a list of keys that are pressed when a
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* new key is pressed or a key that was pressed is released.
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* @led: URB for sending LEDs (e.g. numlock, ...)
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* @newleds: data that will be sent with the @led URB representing which LEDs
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should be on
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* @name: Name of the keyboard. @dev's name field points to this buffer
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* @phys: Physical path of the keyboard. @dev's phys field points to this
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* buffer
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* @new: Buffer for the @irq URB
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* @cr: Control request for @led URB
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* @leds: Buffer for the @led URB
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* @new_dma: DMA address for @irq URB
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* @leds_dma: DMA address for @led URB
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* @leds_lock: spinlock that protects @leds, @newleds, and @led_urb_submitted
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* @led_urb_submitted: indicates whether @led is in progress, i.e. it has been
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* submitted and its completion handler has not returned yet
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* without resubmitting @led
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*/
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struct usb_kbd {
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struct input_dev *dev;
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struct usb_device *usbdev;
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@ -78,6 +104,10 @@ struct usb_kbd {
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unsigned char *leds;
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dma_addr_t new_dma;
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dma_addr_t leds_dma;
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spinlock_t leds_lock;
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bool led_urb_submitted;
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};
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static void usb_kbd_irq(struct urb *urb)
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@ -136,44 +166,66 @@ resubmit:
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static int usb_kbd_event(struct input_dev *dev, unsigned int type,
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unsigned int code, int value)
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{
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unsigned long flags;
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struct usb_kbd *kbd = input_get_drvdata(dev);
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if (type != EV_LED)
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return -1;
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spin_lock_irqsave(&kbd->leds_lock, flags);
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kbd->newleds = (!!test_bit(LED_KANA, dev->led) << 3) | (!!test_bit(LED_COMPOSE, dev->led) << 3) |
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(!!test_bit(LED_SCROLLL, dev->led) << 2) | (!!test_bit(LED_CAPSL, dev->led) << 1) |
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(!!test_bit(LED_NUML, dev->led));
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if (kbd->led->status == -EINPROGRESS)
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if (kbd->led_urb_submitted){
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spin_unlock_irqrestore(&kbd->leds_lock, flags);
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return 0;
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}
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if (*(kbd->leds) == kbd->newleds)
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if (*(kbd->leds) == kbd->newleds){
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spin_unlock_irqrestore(&kbd->leds_lock, flags);
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return 0;
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}
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*(kbd->leds) = kbd->newleds;
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kbd->led->dev = kbd->usbdev;
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if (usb_submit_urb(kbd->led, GFP_ATOMIC))
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pr_err("usb_submit_urb(leds) failed\n");
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else
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kbd->led_urb_submitted = true;
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spin_unlock_irqrestore(&kbd->leds_lock, flags);
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return 0;
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}
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static void usb_kbd_led(struct urb *urb)
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{
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unsigned long flags;
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struct usb_kbd *kbd = urb->context;
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if (urb->status)
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hid_warn(urb->dev, "led urb status %d received\n",
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urb->status);
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if (*(kbd->leds) == kbd->newleds)
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spin_lock_irqsave(&kbd->leds_lock, flags);
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if (*(kbd->leds) == kbd->newleds){
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kbd->led_urb_submitted = false;
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spin_unlock_irqrestore(&kbd->leds_lock, flags);
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return;
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}
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*(kbd->leds) = kbd->newleds;
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kbd->led->dev = kbd->usbdev;
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if (usb_submit_urb(kbd->led, GFP_ATOMIC))
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if (usb_submit_urb(kbd->led, GFP_ATOMIC)){
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hid_err(urb->dev, "usb_submit_urb(leds) failed\n");
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kbd->led_urb_submitted = false;
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}
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spin_unlock_irqrestore(&kbd->leds_lock, flags);
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}
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static int usb_kbd_open(struct input_dev *dev)
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@ -252,6 +304,7 @@ static int usb_kbd_probe(struct usb_interface *iface,
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kbd->usbdev = dev;
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kbd->dev = input_dev;
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spin_lock_init(&kbd->leds_lock);
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if (dev->manufacturer)
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strlcpy(kbd->name, dev->manufacturer, sizeof(kbd->name));
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