On Thu, Dec 07, 2017 at 11:09:11AM -0500, Jason Baron wrote: > On 12/06/2017 06:52 PM, Christoph Hellwig wrote: > > The eoll code currently always uses the unlocked waitqueue helpers for > > ep->wq, but instead of holding the lock inside the waitqueue around these > > calls, as expected by the epoll code uses its own lock. Given that the > > waitqueue is not exposed to the rest of the kernel this actually works > > ok at the moment, but prevents the epoll locking rules from being > > enforced using lockdep. Remove ep->lock and use the waitqueue lock > > to not only reduce the size of struct eventpoll but also make sure we > > can assert locking invariations in the waitqueue code. > > > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> > > Probably should also fix the locking comments at the top of > fs/eventpoll.c that refer to ep->lock... Done. Note that while doing this I noticed that the epoll code seems to have sketchy workarounds for the fact that it abused ep->poll as the waitqueue lock that might be able to be removed now. But I don't really dare to touch the guts of this code.
