Re: [RFC][PATCH] fix short copy handling in copy_mc_pipe_to_iter()

On Tue, Jun 14, 2022 at 01:53:50AM +0100, Al Viro wrote: > FWIW, I've got quite a bit of cleanups in the local tree; reordering and > cleaning that queue up at the moment, will post tonight or tomorrow. > > I've looked into doing allocations page-by-page (instead of single > push_pipe(),

Re: [RFC][PATCH] fix short copy handling in copy_mc_pipe_to_iter()

On Tue, Jun 14, 2022 at 07:36:19AM +0100, David Howells wrote: > Al Viro wrote: > > > What's wrong with > > p_occupancy = pipe_occupancy(head, tail); > > if (p_occupancy >= pipe->max_usage) > > return 0; > > else > > return pipe->max_usage -

Re: [RFC][PATCH] fix short copy handling in copy_mc_pipe_to_iter()

Al Viro wrote: > What's wrong with > p_occupancy = pipe_occupancy(head, tail); > if (p_occupancy >= pipe->max_usage) > return 0; > else > return pipe->max_usage - p_occupancy; Because "pipe->max_usage - p_occupancy" can be negative.