> The fact is, it's not dma-buf that is violating any rules. It's epoll. I agree that epoll() not taking a reference on the file is at least unexpected and contradicts the usual code patterns for the sake of performance and that it very likely is the case that most callers of f_op->poll() don't know this. Note, I cleary wrote upthread that I'm ok to do it like you suggested but raised two concerns a) there's currently only one instance of prolonged @file lifetime in f_op->poll() afaict and b) that there's possibly going to be some performance impact on epoll(). So it's at least worth discussing what's more important because epoll() is very widely used and it's not that we haven't favored performance before. But you've already said that you aren't concerned with performance on epoll() upthread. So afaict then there's really not a lot more to discuss other than take the patch and see whether we get any complaints.
