On Mon, Jan 06, 2025 at 10:42:24PM -0800, Darrick J. Wong wrote:
> So I guess b_io_remaining was the count of in-flight bios?
Yes. Plus a bias of 1 for the submitting context so that the
completion isn't run until all bios are submitted.
> And making a
> chain of bios basically just moves all that to the bio layer, so all
> xfs_buf needs to know is whether or not a bio is in progress, right?
Yes.
> Eerrugh, I spent quite a while trying to wrap my head around the old
> code when I was writing the in-memory xfs_buf support. This is much
> less weird to look at...
>
> > + for (map = 0; map < bp->b_map_count - 1; map++) {
>
> ...but why isn't this "map < bp->b_map_count"?
Because the final ("main") bio is submitted outside the loop as the
loop body chains the ones before to it. I guess this should go into
a comment to confuse the readers a little less.
