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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: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2014-05-26 19:23:48 +02:00 committed by Greg Kroah-Hartman
parent 89e54e4468
commit b1d42efc21
1 changed files with 11 additions and 6 deletions
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17
drivers/usb/class/cdc-acm.c
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@ -590,13 +590,22 @@ static void acm_port_shutdown(struct tty_port *port)
struct urb *urb; struct urb *urb;
struct acm_wb *wb; struct acm_wb *wb;
int i; int i;
int pm_err;
dev_dbg(&acm->control->dev, "%s\n", __func__); dev_dbg(&acm->control->dev, "%s\n", __func__);
pm_err = usb_autopm_get_interface(acm->control);
acm_set_control(acm, acm->ctrlout = 0); 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 (;;) { for (;;) {
urb = usb_get_from_anchor(&acm->delayed); urb = usb_get_from_anchor(&acm->delayed);
if (!urb) if (!urb)
@ -611,10 +620,6 @@ static void acm_port_shutdown(struct tty_port *port)
usb_kill_urb(acm->wb[i].urb); usb_kill_urb(acm->wb[i].urb);
for (i = 0; i < acm->rx_buflimit; i++) for (i = 0; i < acm->rx_buflimit; i++)
usb_kill_urb(acm->read_urbs[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) static void acm_tty_cleanup(struct tty_struct *tty)