On Wed, Jun 6, 2012 at 11:05 PM, Stefani Seibold <stefani@xxxxxxxxxxx> wrote: >> >> This one is not needed since we have minor_rwsem(drivers/usb/core/file.c) >> to avoid the race. >> > > The mutex is not for the minor handling, it is for the disconnect(). As usb_deregister_dev is called by disconnect, and usb_deregister_dev will acquire minor_rwsem, so there is no race between open and disconnect. When skel_open is being called, the minor_rwsem has been held already, so disconnect() will staying on acquiring minor_rwsem. So sync_mutex is not necessary at all. > mentioned in the previous posting, there is a race betwenn open() and > connect(). > > Oliver told me that a interface pointer can be already used by an other > driver when the disconnect() was called. If you mean dev->interface, that is protected by io_mutex already. Thanks, -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
