On Sun, May 05, 2024 at 01:03:07PM -0700, Linus Torvalds wrote: > On Sun, 5 May 2024 at 12:46, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > > > I've no problem with having epoll grab a reference, but if we make that > > a universal requirement ->poll() instances can rely upon, > > Al, we're note "making that a requirement". > > It always has been. Argh. We keep talking past each other. 0. special-cased ->f_count rule for ->poll() is a wart and it's better to get rid of it. 1. fs/eventpoll.c is a steaming pile of shit and I'd be glad to see git rm taken to it. Short of that, by all means, let's grab reference in there around the call of vfs_poll() (see (0)). 2. having ->poll() instances grab extra references to file passed to them is not something that should be encouraged; there's a plenty of potential problems, and "caller has it pinned, so we are fine with grabbing extra refs" is nowhere near enough to eliminate those. 3. dma-buf uses of get_file() are probably safe (epoll shite aside), but they do look fishy. That has nothing to do with epoll.
