USB: convert usb_hcd bitfields into atomic flags

This patch (as1393) converts several of the single-bit fields in
struct usb_hcd to atomic flags.  This is for safety's sake; not all
CPUs can update bitfield values atomically, and these flags are used
in multiple contexts.

The flag fields that are set only during registration or removal can
remain as they are, since non-atomic accesses at those times will not
cause any problems.

(Strictly speaking, the authorized_default flag should become atomic
as well.  I didn't bother with it because it gets changed only via
sysfs.  It can be done later, if anyone wants.)

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 10 insertions, 6 deletions

diff --git a/drivers/usb/host/ohci-hub.c b/drivers/usb/host/ohci-hub.c
index 65cac8cc8921..4dd39022c388 100644
--- a/drivers/usb/host/ohci-hub.c
+++ b/drivers/usb/host/ohci-hub.c
@@ -284,7 +284,7 @@ static int ohci_bus_suspend (struct usb_hcd *hcd)
 
         spin_lock_irq (&ohci->lock);
 
-        if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)))
+        if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
                 rc = -ESHUTDOWN;
         else
                 rc = ohci_rh_suspend (ohci, 0);
@@ -302,7 +302,7 @@ static int ohci_bus_resume (struct usb_hcd *hcd)
 
         spin_lock_irq (&ohci->lock);
 
-        if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)))
+        if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
                 rc = -ESHUTDOWN;
         else
                 rc = ohci_rh_resume (ohci);
@@ -489,7 +489,7 @@ ohci_hub_status_data (struct usb_hcd *hcd, char *buf)
         unsigned long   flags;
 
         spin_lock_irqsave (&ohci->lock, flags);
-        if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags))
+        if (!HCD_HW_ACCESSIBLE(hcd))
                 goto done;
 
         /* undocumented erratum seen on at least rev D */
@@ -533,8 +533,12 @@ ohci_hub_status_data (struct usb_hcd *hcd, char *buf)
                 }
         }
 
-        hcd->poll_rh = ohci_root_hub_state_changes(ohci, changed,
-                        any_connected, rhsc_status);
+        if (ohci_root_hub_state_changes(ohci, changed,
+                        any_connected, rhsc_status))
+                set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
+        else
+                clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
+
 
 done:
         spin_unlock_irqrestore (&ohci->lock, flags);
@@ -701,7 +705,7 @@ static int ohci_hub_control (
         u32             temp;
         int             retval = 0;
 
-        if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)))
+        if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
                 return -ESHUTDOWN;
 
         switch (typeReq) {