USB: make intf.pm_usage an atomic_t

This patch (as1260) changes the pm_usage_cnt field in struct
usb_interface from an int to an atomic_t.  This is so that drivers can
invoke the usb_autopm_get_interface_async() and
usb_autopm_put_interface_async() routines without locking and without
fear of corrupting the pm_usage_cnt value.

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

1 files changed, 3 insertions, 3 deletions

diff --git a/include/linux/usb.h b/include/linux/usb.h
index 3b45a0d27b80..a34fa89f1474 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -195,7 +195,7 @@ struct usb_interface {
 
         struct device dev;              /* interface specific device info */
         struct device *usb_dev;
-        int pm_usage_cnt;               /* usage counter for autosuspend */
+        atomic_t pm_usage_cnt;          /* usage counter for autosuspend */
         struct work_struct reset_ws;    /* for resets in atomic context */
 };
 #define to_usb_interface(d) container_of(d, struct usb_interface, dev)
@@ -551,13 +551,13 @@ extern void usb_autopm_put_interface_async(struct usb_interface *intf);
 
 static inline void usb_autopm_enable(struct usb_interface *intf)
 {
-        intf->pm_usage_cnt = 0;
+        atomic_set(&intf->pm_usage_cnt, 0);
         usb_autopm_set_interface(intf);
 }
 
 static inline void usb_autopm_disable(struct usb_interface *intf)
 {
-        intf->pm_usage_cnt = 1;
+        atomic_set(&intf->pm_usage_cnt, 1);
         usb_autopm_set_interface(intf);
 }