From: Stefani Seibold <stefani@xxxxxxxxxxx> This is a fix for the USB skeleton driver to bring it in shape. - The usb_interface structure pointer will be no longer stored - Every access to the USB will be handled trought the usb_interface pointer - Add a new bool 'connected' for signaling a disconnect (== false) - Handle a non blocking read without blocking - Code cleanup - Synchronize disconnect() handler with open() and release(), to fix races - Introduced fsync - Single user mode - Eliminated dead code - Save some bytes in the dev structure Some word about the open()/release() races with disconnect() of an USB device (which can happen any time): - The return interface pointer from usb_find_interface() could be already owned by an other driver and no more longer handle by the skeleton driver. - Or the dev pointer return by usb_get_intfdata() could point to an already release memory. This races can not handled by a per device mutex. Only a driver global mutex could do this job, since the kref_put() in the skel_disconnect() must be protected, otherwise skel_open() could access an already released memory. I know that this races are very small, but on heavy load or misdesigned or buggy hardware this could lead in a OOPS or unpredictable behavior. The patch is against linux 3.5.0 commit eea5b5510fc5545d15b69da8e485a7424ae388cf Hope this helps Signed-off-by: Stefani Seibold <stefani@xxxxxxxxxxx> -- 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
