On Thu, Jun 29, 2017 at 02:25:00PM -0700, Christoph Hellwig wrote: > This series resurrects the old patches from Milosz to implement > non-blocking buffered reads. Thanks to the non-blocking AIO code from > Goldwyn the implementation becomes pretty much trivial. As that > implementation is in the block tree I would suggest that we merge > these patches through the block tree as well. I've also forward > ported the test Milosz sent for recent xfsprogs to verify it works > properly, but I'll still have to address the review comments for it. > I'll also volunteer to work with Goldwyn to properly document the > RWF_NOWAIT flag in the man page including this change.
Hmm... It's not quite non-blocking, though - copy_page_to_iter() can bloody well block, as any copying to userland. I'm not saying that it's a significant problem (if you are reading into something that had been mmaped from NFS server, etc., you are getting what you'd asked for), but it's worth documenting.
