Hi, There are still a few users of fops->read() in the core parts of the fs stack. Which is a shame, since it'd be nice to get rid of the non-iterator parts of down the line, and reclaim that part of the file_operations struct. Outside of moving in that direction as a cleanup, using ->read_iter() enables us to mark them with FMODE_NOWAIT. This is important for users like io_uring, where per-IO nonblocking hints make a difference in how efficiently IO can be done. Those two things are my main motivation for starting this work, with hopefully more to come down the line. All patches have been booted and tested, and the corresponding test cases been run. The timerfd one was sent separately previously, figured I'd do a few more and make a smaller series out of it. -- Jens Axboe