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Commit b1d42efc authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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USB: cdc-acm: minimise no-suspend window during shutdown 



Now that acm_set_control() handles runtime PM properly, the only
remaining reason for the PM operations in shutdown is to clear the
needs_remote_wakeup flag before the final put.

Note that this also means that we now need to grab the write_lock to
prevent racing with resume.

Signed-off-by: default avatarJohan Hovold <jhovold@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 89e54e44

drivers/usb/class/cdc-acm.c

+11 −6
Original line number Diff line number Diff line
@@ -590,13 +590,22 @@ static void acm_port_shutdown(struct tty_port *port) 
	struct urb *urb;

	struct acm_wb *wb;

	int i;

	int pm_err;



	dev_dbg(&acm->control->dev, "%s\n", __func__);



	pm_err = usb_autopm_get_interface(acm->control);

	acm_set_control(acm, acm->ctrlout = 0);



	/*

	 * Need to grab write_lock to prevent race with resume, but no need to

	 * hold it due to the tty-port initialised flag.

	 */

	spin_lock_irq(&acm->write_lock);

	spin_unlock_irq(&acm->write_lock);



	usb_autopm_get_interface_no_resume(acm->control);

	acm->control->needs_remote_wakeup = 0;

	usb_autopm_put_interface(acm->control);



	for (;;) {

		urb = usb_get_from_anchor(&acm->delayed);

		if (!urb)
@@ -611,10 +620,6 @@ static void acm_port_shutdown(struct tty_port *port) 
		usb_kill_urb(acm->wb[i].urb);

	for (i = 0; i < acm->rx_buflimit; i++)

		usb_kill_urb(acm->read_urbs[i]);



	acm->control->needs_remote_wakeup = 0;

	if (!pm_err)

		usb_autopm_put_interface(acm->control);

}



static void acm_tty_cleanup(struct tty_struct *tty)