On Wed, Apr 29, 2026 at 03:26:06PM +0300, Ilpo Järvinen wrote:
> pci_resource_alignment() returns 0 when resource is already assigned
> and in case of disabled bridge windows. This has caused problems to
> calculations relying on pci_resource_alignment():
>
> https://lore.kernel.org/linux-pci/LV8P221MB1472A24B9975F7C8E8D6BF929947A@LV8P221MB1472.NAMP221.PROD.OUTLOOK.COM/
>
> This series reworks pci_resource_alignment() interface to return always
> non-zero alignment if the resource exists. For assigned bridge windows,
> the calculation is using heuristic based on size and start address
> alignment as calculating the alignment again is costly (would require
> sizing the entire sub-hierarchy).
>
> As pci_resource_alignment() is becoming more complicated, it's also
> moved to setup-res.c. While moving pci_resource_alignment()'s arguments
> are converted into const to tell compiler it can rely on resource
> remaining the same across the call.
>
> This was intended to be part of a larger series that addresses some
> shortcomings in pci=realloc. The pci=realloc changes will recalculate
> bridge window sizes considering also assigned resources which required
> making these changes to pci_resource_alignment().
>
> As this also relates to the issue linked above, I'm sending it already
> now without pci=realloc changes that are still incomplete. The first
> patches originate from the large pci=realloc work but seem generally
> useful even if independent of the alignment improvements so I've
> included them here without reorganizing the series to contain only
> alignment related changes.
>
> Ilpo Järvinen (11):
> PCI: Log all resource claims
> PCI: Rename added to add_list
> PCI: Consolidate add_list (aka realloc_head) empty sanity checks
> PCI: Remove const removal cast
> resource: Make resource_alignment() input const resource
> powerpc/pseries: Make pseries_get_iov_fw_value() & pnv_iov_get()
> pci_dev const
> PCI: Make pci_sriov_resource_alignment() pci_dev const
> PCI: Convert pci_resource_alignment() input parameters to const
> PCI: Move pci_resource_alignment() to setup-res.c file
> PCI: Lower bound bridge windown alignment
> PCI: Return valid alignment for assigned resources
>
> arch/powerpc/include/asm/machdep.h | 2 +-
> arch/powerpc/kernel/pci-common.c | 2 +-
> arch/powerpc/platforms/powernv/pci-sriov.c | 4 +-
> arch/powerpc/platforms/powernv/pci.h | 5 ++-
> arch/powerpc/platforms/pseries/setup.c | 5 ++-
> drivers/pci/iov.c | 7 +--
> drivers/pci/pci.h | 24 ++++-------
> drivers/pci/setup-bus.c | 50 ++++++++++++----------
> drivers/pci/setup-cardbus.c | 2 +-
> drivers/pci/setup-res.c | 37 ++++++++++++++++
> include/linux/ioport.h | 2 +-
> include/linux/pci.h | 8 ++--
> kernel/resource.c | 2 +-
> 13 files changed, 94 insertions(+), 56 deletions(-)
Applied to pci/resource for v7.2, thanks!
Powerpc folks, the arch/powerpc changes here are minor (just adding
const), but heads up in case you see any issue.