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>

1 files changed, 6 insertions, 11 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 6bbd203f1861..bc7a2a6fc4ac 100644
--- 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;
 }