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: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 6bbd203..bc7a2a6 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -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;
 }