HID: usbhid: use irqsave() in USB's complete callback

HID: usbhid: use irqsave() in USB's complete callback

[Sebastian Andrzej Siewior]

The USB completion callback does not disable interrupts while acquiring
the ->lock. We want to remove the local_irq_disable() invocation from
__usb_hcd_giveback_urb() and therefore it is required for the callback
handler to disable the interrupts while acquiring the lock.
The callback may be invoked either in IRQ or BH context depending on the
USB host controller.
Use the _irqsave() variant of the locking primitives.

Cc: Jiri Kosina <jikos@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: linux-input@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/hid/usbhid/hid-core.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index af0e0d061b15..11103efebbaa 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -480,6 +480,7 @@ static void hid_ctrl(struct urb *urb)
 {
 	struct hid_device *hid = urb->context;
 	struct usbhid_device *usbhid = hid->driver_data;
+	unsigned long flags;
 	int unplug = 0, status = urb->status;
 
 	switch (status) {
@@ -501,7 +502,7 @@ static void hid_ctrl(struct urb *urb)
 		hid_warn(urb->dev, "ctrl urb status %d received\n", status);
 	}
 
-	spin_lock(&usbhid->lock);
+	spin_lock_irqsave(&usbhid->lock, flags);
 
 	if (unplug) {
 		usbhid->ctrltail = usbhid->ctrlhead;
@@ -511,13 +512,13 @@ static void hid_ctrl(struct urb *urb)
 		if (usbhid->ctrlhead != usbhid->ctrltail &&
 				hid_submit_ctrl(hid) == 0) {
 			/* Successfully submitted next urb in queue */
-			spin_unlock(&usbhid->lock);
+			spin_unlock_irqrestore(&usbhid->lock, flags);
 			return;
 		}
 	}
 
 	clear_bit(HID_CTRL_RUNNING, &usbhid->iofl);
-	spin_unlock(&usbhid->lock);
+	spin_unlock_irqrestore(&usbhid->lock, flags);
 	usb_autopm_put_interface_async(usbhid->intf);
 	wake_up(&usbhid->wait);
 }

HID: usbhid: use irqsave() in USB's complete callback

[Jiri Kosina]

On Tue, 19 Jun 2018, Sebastian Andrzej Siewior wrote:

> The USB completion callback does not disable interrupts while acquiring
> the ->lock. We want to remove the local_irq_disable() invocation from
> __usb_hcd_giveback_urb() and therefore it is required for the callback
> handler to disable the interrupts while acquiring the lock.
> The callback may be invoked either in IRQ or BH context depending on the
> USB host controller.
> Use the _irqsave() variant of the locking primitives.

Applied, thanks.