Re: [RFC PATCH 00/32] separate operations from flags in the bio/request structs

From: Mike Snitzer
Date: Wed Nov 11 2015 - 12:37:32 EST

On Wed, Nov 11 2015 at 6:28am -0500,
Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:

> On Wed, Nov 11, 2015 at 01:53:24AM -0600, Mike Christie wrote:
> > We no longer have the bvec merge functions so the original reason given
> > in the thread/patch Bart referenced is no longer valid.
> >
> > Offlist it was suggested that dropping the argument from submit_bio
> > might still improve performance, but I modified xfs and dm and did some
> > testing and did not see anything.
> >
> > So the change is not needed, and it would only be done because people
> > feel it would improve the interface.
> I would defintively prefer the changed interface, and to me it also
> looks like it would make your overall patch simpler. If you disagree
> feel free to keep it as-is for now and I'll do another pass later.

The less churn the better. But honestly, not quite following the logic
on why all this flag-day churn is needed. BUT if it needs to happen,
because we'll soon hit a wall on supported operations via REQ_*, now is
as good a time as any -- but best to limit the change to the flags IMHO.
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