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Commit bbf0cb3e authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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USB: cdc-acm: simplify runtime PM locking 



We can simply the runtime PM locking as there's no need to check the
susp_count in the read path (at least not since killing the rx tasklet).

Specifically, the read urbs will never be resubmitted by the completion
handler when killed during suspend.

Signed-off-by: default avatarJohan Hovold <jhovold@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5292afa6

drivers/usb/class/cdc-acm.c

+6 −11
Original line number Diff line number Diff line
@@ -428,7 +428,7 @@ static void acm_read_bulk_callback(struct urb *urb) 
	/* throttle device if requested by tty */

	spin_lock_irqsave(&acm->read_lock, flags);

	acm->throttled = acm->throttle_req;

	if (!acm->throttled && !acm->susp_count) {

	if (!acm->throttled) {

		spin_unlock_irqrestore(&acm->read_lock, flags);

		acm_submit_read_urb(acm, rb->index, GFP_ATOMIC);

	} else {
@@ -1546,18 +1546,15 @@ static int acm_suspend(struct usb_interface *intf, pm_message_t message) 
	struct acm *acm = usb_get_intfdata(intf);

	int cnt;



	spin_lock_irq(&acm->read_lock);

	spin_lock(&acm->write_lock);

	spin_lock_irq(&acm->write_lock);

	if (PMSG_IS_AUTO(message)) {

		if (acm->transmitting) {

			spin_unlock(&acm->write_lock);

			spin_unlock_irq(&acm->read_lock);

			spin_unlock_irq(&acm->write_lock);

			return -EBUSY;

		}

	}

	cnt = acm->susp_count++;

	spin_unlock(&acm->write_lock);

	spin_unlock_irq(&acm->read_lock);

	spin_unlock_irq(&acm->write_lock);



	if (cnt)

		return 0;
@@ -1573,8 +1570,7 @@ static int acm_resume(struct usb_interface *intf) 
	struct urb *urb;

	int rv = 0;



	spin_lock_irq(&acm->read_lock);

	spin_lock(&acm->write_lock);

	spin_lock_irq(&acm->write_lock);



	if (--acm->susp_count)

		goto out;
@@ -1600,8 +1596,7 @@ static int acm_resume(struct usb_interface *intf) 
		rv = acm_submit_read_urbs(acm, GFP_ATOMIC);

	}

out:

	spin_unlock(&acm->write_lock);

	spin_unlock_irq(&acm->read_lock);

	spin_unlock_irq(&acm->write_lock);



	return rv;

}