From 4685be25a19078de6301f50bde7a755483805269 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Mon, 25 Jun 2018 00:08:34 +0200 Subject: [PATCH] usb: cdc-acm: use irqsave() in USB's complete callback 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: Oliver Neukum Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index ed0475c..24686f8 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -276,6 +276,7 @@ static void acm_process_notification(struct acm *acm, unsigned char *buf) { int newctrl; int difference; + unsigned long flags; struct usb_cdc_notification *dr = (struct usb_cdc_notification *)buf; unsigned char *data = buf + sizeof(struct usb_cdc_notification); @@ -303,7 +304,7 @@ static void acm_process_notification(struct acm *acm, unsigned char *buf) } difference = acm->ctrlin ^ newctrl; - spin_lock(&acm->read_lock); + spin_lock_irqsave(&acm->read_lock, flags); acm->ctrlin = newctrl; acm->oldcount = acm->iocount; @@ -321,7 +322,7 @@ static void acm_process_notification(struct acm *acm, unsigned char *buf) acm->iocount.parity++; if (difference & ACM_CTRL_OVERRUN) acm->iocount.overrun++; - spin_unlock(&acm->read_lock); + spin_unlock_irqrestore(&acm->read_lock, flags); if (difference) wake_up_all(&acm->wioctl); -- 2.7.4