By default, if a caller sets REQ_NOWAIT and we need to block, we'll
return -EAGAIN through the bio->bi_end_io() callback. For some use
cases, this makes it hard to use.
Allow a caller to ask for inline return of errors related to
blocking by also setting REQ_NOWAIT_INLINE.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
893a1c9720