On Fri, Nov 30, 2018 at 10:17:49AM -0700, Jens Axboe wrote: > > Setting REQ_NOWAIT from inside the block layer will make the code that > > submits requests harder to review. Have you considered to make this code > > fail I/O if REQ_NOWAIT has not been set and to require that the context > > that submits I/O sets REQ_NOWAIT? > > It's technically still feasible to do for sync polled IO, it's only > the async case that makes it a potential deadlock. I wonder if we want a REQ_ASYNC_POLL compound flag #define that sets REQ_POLL and REQ_NOWAIT to make this blindly obvious.