On 8/25/26 3:26 PM, Matthew Rosato wrote:
Given that, should the #define be sizeof(IplBlockPci) + 24?
If IplBlockPci is likely to expand in the future, it might make sense to
derive this value from the structure layout. For example,
offsetof(IplParameterBlock, pci) + sizeof(IplBlockPci) could be more
accurate. Otherwise, keeping it as a constant like the other definitions
seems reasonable as well.
All of those suggestions would be valid, but I'm leaning toward keeping it
defined without using sizeof() for the sake of consistency if nothing
else. The other IPLB types are already defined as fixed numbers and for
the IplBlockQemuScsi being used later in this patch series, it actually has
a minimum value that is less than the sizeof() itself due to the same
struct
servicing both PCI and CCW controllers, where the minimum size for CCW is
less than PCI.
I can envision several ways to improve the definitions and/or naming
conventions, but I think it is outside the scope of this series because the
changes should be uniformly applied to all definitions, not just PCI.
Ehh... If you already think the other definitions should be fixed then
convention is not a good enough reason to propagate the bad practice to
new code. Doing the new definition the right way now in this patch is
certainly within the scope of this series.
If we have structures that define the entire 336 bytes, I personally
would much prefer to see that written out with sizeof()s vs a magic
number that coincidentally must line up with the size of one or more
well-defined structures.
As for existing definitions, I agree that is out of scope: you could
follow-up later with one or more patches that cleanup the existing
definitions.
Thanks,
Matt
OK. I will use offsetof(IplParameterBlock, pci) + sizeof(IplBlockPci) for
the new definition, with the intention of cleanly splitting the IPLB header
from Block0 and uniformly updating the definitions in a follow-up series
later.
Regards,
Jared Rossi
