lkml.org 
[lkml]   [2018]   [Sep]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH v2] PCI hotplug Eq v2
Date
On Mon, 2018-09-17 at 15:53 -0500, Bjorn Helgaas wrote:
> On Thu, Aug 30, 2018 at 04:11:59PM -0600, Jon Derrick wrote:
> > Hi Bjorn,
> >
> > Sorry for the delay on this one and pushing it after RC1.
> > Feel free to queue it up for 4.20 if it looks fine.
> >
> > I've added comments to the git log and source explaining why
> > calculate_iosize was left unchanged. Basically I could not
> > synthesize a condition where it would have affected the topology.
>
> In other words, the only reason you didn't change the
> calculate_iosize() path was because you couldn't test it?
>
I did unsuccessfully try to synthesize it in hardware and qemu. The
firmwares didn't provide the neccessary topology to hit the flexible IO
provisioning conditions


> I appreciate your desire to avoid untested changes, but I think it's
> very important to preserve and even improve the symmetry between
> calculate_memsize() and calculate_iosize(). For example, it's not
> obvious why the order is different here:
>
> calculate_iosize():
> size = ALIGN(size + size1, align);
> if (size < old_size)
> size = old_size;
>
I agree this part didn't make that much sense to me, which was another
reason I left it as-is. Looking at it again, I think its a harmless
calculation that bounds IO size tightly, but could also be reordered as
below to provide for the additional IO (assuming this code ever runs).

> calculate_memsize():
> if (size < old_size)
> size = old_size;
> size = ALIGN(size + size1, align);
>
> So I don't want to diverge them further unless there's a real
> functional reason why we need to handle I/O port space differently
> than MMIO space.
>
> You've tested the MMIO path, and I'm willing to take the risk of
> doing the same thing in the I/O port path.
>
> Bjorn
Great! I'll follow-up with a patch as soon as I can

Jon
[unhandled content-type:application/x-pkcs7-signature]
\
 
 \ /
  Last update: 2018-09-17 23:03    [W:0.687 / U:0.100 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site