On Fri, Oct 09, 2020 at 06:03:31PM -0700, Linus Torvalds wrote: > On Fri, Oct 9, 2020 at 3:06 PM Eric Biggers <ebiggers@xxxxxxxxxx> wrote: > > > > It's a bit unintuitive that ppos=NULL means "use pos 0", not "use file->f_pos". > > That's not at all what it means. > > A NULL ppos means "this has no position at all", and is what we use > for FMODE_STREAM file descriptors (ie sockets, pipes, etc). > > It also means that we don't do the locking for position updates. > > The fact that "ki_pos" gets set to zero is just because it needs to be > _something_. It shouldn't actually ever be used for stream devices. > Okay, that makes more sense. So the patchset from Matthew https://lkml.kernel.org/linux-fsdevel/20201003025534.21045-1-willy@xxxxxxxxxxxxx/T/#u isn't what you had in mind. - Eric
