Re: [PATCH 0/4] dm: zoned block device fixes

[Mike Snitzer <snitzer@redhat.com>]

On Mon, Jun 05 2017 at  6:48am -0400,
Damien Le Moal <damien.lemoal@wdc.com> wrote:
 
> I did address some of the "FIXME" notes you added. The main one is the
> BIO cloning in the I/O path. I removed most of that and added a .end_io
> method for completion processing. The only place were I do not see how
> to remove the call to bio_clone() is during read BIO processing: since a
> read BIO may end up being split between buffer zone, sequential zone and
> simple buffer zero-out, fragmentation of the read BIO is sometimes
> necessary and so need a clone.

So shouldn't it be possible to not allow a given bio to cross zone
boundaries by using dm_accept_partial_bio()?

Like you're already doing in dmz_map() actually... so why do you need to
account for crossing zone boundaries on read later on in
dmz_submit_read_bio()?

Is it that these zones aren't easily known up front (in dmz_map)?

Mike