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How to best make include/hw/pci/pcie_sriov.h self-contained
From: |
Markus Armbruster |
Subject: |
How to best make include/hw/pci/pcie_sriov.h self-contained |
Date: |
Wed, 07 Dec 2022 07:25:49 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) |
pcie_sriov.h needs PCI_NUM_REGIONS from pci.h, but doesn't include it.
pci.h must be included before pcie_sriov.h or else compile fails.
Adding #include "pci/pci.h" to pcie_sriov would be wrong, because it
would close an inclusion loop: pci.h includes pcie.h (for
PCIExpressDevice) includes pcie_sriov.h (for PCIESriovPF) includes pci.h
(for PCI_NUM_REGIONS).
The obvious solution is to move PCI_NUM_REGIONS pci.h somewhere
pcie_sriov.h can include without creating a loop.
We already have a few headers that don't include anything: pci_ids.h,
pci_regs.h (includes include/standard-headers/linux/pci_regs.h, which
doesn't count), pcie_regs.h. Moving PCI_NUM_REGIONS to one of these
would work, but it doesn't feel right.
We could create a new one, say pci_defs.h. Just for PCI_NUM_REGIONS
feels silly. So, what else should move there?
Any other ideas?
In case you wonder why I bother you with this...
Back in 2016, we discussed[1] rules for headers, and these were
generally liked:
1. Have a carefully curated header that's included everywhere first. We
got that already thanks to Peter: osdep.h.
2. Headers should normally include everything they need beyond osdep.h.
If exceptions are needed for some reason, they must be documented in
the header. If all that's needed from a header is typedefs, put
those into qemu/typedefs.h instead of including the header.
3. Cyclic inclusion is forbidden.
I'm working on patches to get include/ closer to obeying 2.
[1] Message-ID: <87h9g8j57d.fsf@blackfin.pond.sub.org>
https://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg03345.html
- How to best make include/hw/pci/pcie_sriov.h self-contained,
Markus Armbruster <=