USB: keep track of whether interface sysfs files exist

This patch (as1009) solves the problem of multiple registrations for
USB sysfs files in a more satisfying way than the existing code.  It
simply adds a flag to keep track of whether or not the files have been
created; that way the files can be created or removed as needed.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>

3 files changed, 9 insertions, 10 deletions

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 316a746e008..40fd39de5bf 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1172,7 +1172,6 @@ int usb_set_interface(struct usb_device *dev, int interface, int alternate)
         struct usb_host_interface *alt;
         int ret;
         int manual = 0;
-        int changed;
 
         if (dev->state == USB_STATE_SUSPENDED)
                 return -EHOSTUNREACH;
@@ -1212,8 +1211,7 @@ int usb_set_interface(struct usb_device *dev, int interface, int alternate)
          */
 
         /* prevent submissions using previous endpoint settings */
-        changed = (iface->cur_altsetting != alt);
-        if (changed && device_is_registered(&iface->dev))
+        if (iface->cur_altsetting != alt && device_is_registered(&iface->dev))
                 usb_remove_sysfs_intf_files(iface);
         usb_disable_interface(dev, iface);
 
@@ -1250,7 +1248,7 @@ int usb_set_interface(struct usb_device *dev, int interface, int alternate)
          * (Likewise, EP0 never "halts" on well designed devices.)
          */
         usb_enable_interface(dev, iface);
-        if (changed && device_is_registered(&iface->dev))
+        if (device_is_registered(&iface->dev))
                 usb_create_sysfs_intf_files(iface);
 
         return 0;
@@ -1641,12 +1639,6 @@ free_interfaces:
                                 intf->dev.bus_id, ret);
                         continue;
                 }
-
-                /* The driver's probe method can call usb_set_interface(),
-                 * which would mean the interface's sysfs files are already
-                 * created.  Just in case, we'll remove them first.
-                 */
-                usb_remove_sysfs_intf_files(intf);
                 usb_create_sysfs_intf_files(intf);
         }
 
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index b04afd06e50..32bd130b1ee 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -735,6 +735,8 @@ int usb_create_sysfs_intf_files(struct usb_interface *intf)
         struct usb_host_interface *alt = intf->cur_altsetting;
         int retval;
 
+        if (intf->sysfs_files_created)
+                return 0;
         retval = sysfs_create_group(&dev->kobj, &intf_attr_grp);
         if (retval)
                 return retval;
@@ -746,6 +748,7 @@ int usb_create_sysfs_intf_files(struct usb_interface *intf)
         if (intf->intf_assoc)
                 retval = sysfs_create_group(&dev->kobj, &intf_assoc_attr_grp);
         usb_create_intf_ep_files(intf, udev);
+        intf->sysfs_files_created = 1;
         return 0;
 }
 
@@ -753,8 +756,11 @@ void usb_remove_sysfs_intf_files(struct usb_interface *intf)
 {
         struct device *dev = &intf->dev;
 
+        if (!intf->sysfs_files_created)
+                return;
         usb_remove_intf_ep_files(intf);
         device_remove_file(dev, &dev_attr_interface);
         sysfs_remove_group(&dev->kobj, &intf_attr_grp);
         sysfs_remove_group(&intf->dev.kobj, &intf_assoc_attr_grp);
+        intf->sysfs_files_created = 0;
 }
diff --git a/include/linux/usb.h b/include/linux/usb.h
index c5c8f169d3c..416ee7617d9 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -157,6 +157,7 @@ struct usb_interface {
                                          * bound to */
         enum usb_interface_condition condition;         /* state of binding */
         unsigned is_active:1;           /* the interface is not suspended */
+        unsigned sysfs_files_created:1; /* the sysfs attributes exist */
         unsigned needs_remote_wakeup:1; /* driver requires remote wakeup */
 
         struct device dev;              /* interface specific device info */