On Sat, Nov 17, 2018 at 04:53:15PM -0700, Jens Axboe wrote:

Add the field and have the blockdev direct_IO() helpers set it.
This is in preparation for being able to poll for iocb completion.

What purpose does this field serve?

And why add it to just blockdev direct_IO and not the other direct
IO paths, too?

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com