Re: Portmasters alert: was => Re: uvm physseg - put the lid on it.

[Taylor R Campbell <campbell+netbsd-tech-kern%mumble.net@localhost>]

   Date: Sun, 25 Dec 2016 00:40:44 +0530
   From: Cherry G. Mathew <cherry%zyx.in@localhost>

   Sorry about that - acorn26, sh3 and evbppc related builds should now be
   fixed.

OK, thanks!

       Taylor> In addition to fixing the build, it would be helpful to
       Taylor> be able to review changes to fix the build more than
       Taylor> cursorily via the autobuild status.

   I'm not sure I understand this comment. Are you saying you need more
   information about why the builds are failing/what the fixes are ?

I was just asking for a little more than simply committing a fix for
the builds, so that if someone else were to commit a fix I could
review that change and decide whether or not it is correct.

The uvm_hotplug(9) man page tells me what the API looks like *now*,
but not what it used to look like or how it changed from that.  For a
made up example, maybe where you used to write

   physseg = vm_physseg[i];

to get the ith physseg, you now write

   physseg = uvm_hotplug_get_physseg(i);

and you must afterward write

   uvm_hotplug_put_physseg(physseg);

when you're done with it.

For a real example, dholland sometimes maintains a list of VFS API
changes along these lines:

https://www.NetBSD.org/~dholland/outoftree.html

E.g.,

  `The interface to the name cache was changed around to disentangle
   it from struct componentname and namei internals.  This is actually
   two changes committed on top of each other.  The first, in typical
   usage, changes

      if ((error = cache_lookup(vdp, vpp, cnp)) >= 0)
              return error;

   to

      if (cache_lookup(vdp, cnp, NULL, vpp)) {
              return *vpp == NULLVP ? ENOENT : 0;

   that is, the order of the arguments is fixed to put the result
   parameter last /and/ the sense of the return value changes....'

With this summary, I can quickly review a change to a call to
cache_lookup by seeing whether it matches this pattern or is
different.