[PATCH v3 0/8] PCI: Solve two bridge window sizing issues

From: Ilpo Järvinen
Date: Tue May 07 2024 - 06:25:55 EST


Hi all,

Here's a series that contains two fixes to PCI bridge window sizing
algorithm. Together, they should enable remove & rescan cycle to work
for a PCI bus that has PCI devices with optional resources and/or
disparity in BAR sizes.

For the second fix, I chose to expose find_resource_space() from
kernel/resource.c because it should increase accuracy of the cannot-fit
decision (currently that function is called find_resource()). In order
to do that sensibly, a few improvements seemed in order to make its
interface and name of the function sane before exposing it. Thus, the
few extra patches on resource side.

v3:
- Removed "slot" wording
- Renamed find_empty_resource_slot() -> find_resource_space()
- find_resource_space() returns bool instead of int
- Added patch to convert literal 20 related to bridge win minimum
alignment to __ffs(SZ_1M)
- Fixed kerneldoc missing "struct"
- Tweaked prints (one dbg -> info, added new dbg one for success case)
- Changelog tweaks
- Take account largest >> 1 (in alignment calc)
- Adjust to minor changes made into calculate_memsize()
- Take logs from more recent kernel to get rid of reg 0xXX

v2:
- Add "typedef" to kerneldoc to get correct formatting
- Use RESOURCE_SIZE_MAX instead of literal
- Remove unnecessary checks for io{port/mem}_resource
- Apply a few style tweaks from Andy

Ilpo Järvinen (8):
PCI: Fix resource double counting on remove & rescan
resource: Rename find_resource() to find_resource_space()
resource: Document find_resource_space() and resource_constraint
resource: Use typedef for alignf callback
resource: Handle simple alignment inside __find_resource_space()
resource: Export find_resource_space()
PCI: Make minimum bridge window alignment reference more obvious
PCI: Relax bridge window tail sizing rules

drivers/pci/bus.c | 10 +----
drivers/pci/setup-bus.c | 91 +++++++++++++++++++++++++++++++++++++----
include/linux/ioport.h | 44 ++++++++++++++++++--
include/linux/pci.h | 5 +--
kernel/resource.c | 68 ++++++++++++++----------------
5 files changed, 157 insertions(+), 61 deletions(-)

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2.39.2