On Thu, Apr 19, 2018 at 01:26:10PM -0400, Jerome Glisse wrote: > Basicly i want a callback in __fd_install(), do_dup2(), dup_fd() and > add void * *private_data; to struct fdtable (also a default array to > struct files_struct). The callback would be part of struct file_operations. > and only call if it exist (os overhead is only for device driver that > care). Hell, *NO*. This is insane - you would need to maintain extra counts ("how many descriptors refer to this struct file... for this descriptor table"). Besides, _what_ private_data? What would own and maintain it? A specific driver? What if more than one of them wants that thing? > Did i miss something fundamental ? copy_files() call dup_fd() so i > should be all set here. That looks like an extremely misguided kludge for hell knows what purpose, almost certainly architecturally insane. What are you actually trying to achieve?