USB: don't register endpoints for interfaces that are going away

This patch (as1155) fixes a bug in usbcore.  When interfaces are
deleted, either because the device was disconnected or because of a
configuration change, the extra attribute files and child endpoint
devices may get left behind.  This is because the core removes them
before calling device_del().  But during device_del(), after the
driver is unbound the core will reinstall altsetting 0 and recreate
those extra attributes and children.

The patch prevents this by adding a flag to record when the interface
is in the midst of being unregistered.  When the flag is set, the
attribute files and child devices will not be created.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org> [2.6.27, 2.6.26, 2.6.25]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 2 insertions, 1 deletions

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 887738577b28..6d1048faf08e 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1091,6 +1091,7 @@ void usb_disable_device(struct usb_device *dev, int skip_ep0)
                                 continue;
                         dev_dbg(&dev->dev, "unregistering interface %s\n",
                                 dev_name(&interface->dev));
+                        interface->unregistering = 1;
                         usb_remove_sysfs_intf_files(interface);
                         device_del(&interface->dev);
                 }
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index f66fba11fbd5..4fb65fdc9dc3 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -840,7 +840,7 @@ 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)
+        if (intf->sysfs_files_created || intf->unregistering)
                 return 0;
 
         /* The interface string may be present in some altsettings