[patch 00/32] genirq/msi, PCI/MSI: Spring cleaning - Part 2

Thomas Gleixner
2021-11-27T01:31:52Z

This is the third part of [PCI]MSI refactoring which aims to provide the
ability of expanding MSI-X vectors after enabling MSI-X.

The first two parts of this work can be found here:

https://lore.kernel.org/r/20211126222700.862407977@linutronix.de
https://lore.kernel.org/r/20211126224100.303046749@linutronix.de

This third part has the following important changes:

1) Add locking to protect the MSI descriptor storage

Right now the MSI descriptor storage (linked list) is not protected
by anything under the assumption that the list is installed before
use and destroyed after use. As this is about to change there has to
be protection

2) A new set of iterators which allow filtering on the state of the
descriptors namely whether a descriptor is associated to a Linux
interrupt or not.

This cleans up a lot of use cases which have to do this filtering
manually.

3) A new set of MSI descriptor allocation functions which make the usage
sites simpler and confine the storage handling to the core code.

Trivial MSI descriptors (non PCI) are now allocated by the core code
automatically when the underlying irq domain requests that.

4) Rework of sysfs handling to prepare for dynamic extension of MSI-X

The current mechanism which creates the directory and the attributes
for all MSI descriptors in one go is obviously not suitable for
dynamic extension. The rework splits the directory creation out and
lets the MSI interrupt allocation create the per descriptor
attributes.

5) Conversion of the MSI descriptor storage to xarray

The linked list based storage is suboptimal even without dynamic
expansion as it requires full list walks to get to a specific
descriptor. With dynamic expansion this gets even more
convoluted. Xarray is way more suitable and simplifies the
final goal of dynamic expansion of the MSI-X space.

The series is based on:

git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git msi-v1-part-2

and also available from git:

git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git msi-v1-part-3

For the curious who can't wait for the next part to arrive the full series
is available via:

git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git msi-v1-part-4

Thanks,

tglx
---
.clang-format | 1
arch/powerpc/platforms/4xx/hsta_msi.c | 7
arch/powerpc/platforms/cell/axon_msi.c | 7
arch/powerpc/platforms/pasemi/msi.c | 9
arch/powerpc/sysdev/fsl_msi.c | 8
arch/powerpc/sysdev/mpic_u3msi.c | 9
arch/s390/pci/pci_irq.c | 6
arch/x86/pci/xen.c | 14
drivers/base/core.c | 3
drivers/base/platform-msi.c | 110 -----
drivers/bus/fsl-mc/fsl-mc-msi.c | 61 --
drivers/ntb/msi.c | 19
drivers/pci/controller/pci-hyperv.c | 15
drivers/pci/msi/irqdomain.c | 11
drivers/pci/msi/legacy.c | 20
drivers/pci/msi/msi.c | 255 +++++------
drivers/pci/xen-pcifront.c | 2
drivers/soc/ti/ti_sci_inta_msi.c | 77 +--
include/linux/device.h | 4
include/linux/msi.h | 135 +++++-
include/linux/soc/ti/ti_sci_inta_msi.h | 1
kernel/irq/msi.c | 719 ++++++++++++++++++++++-----------
22 files changed, 841 insertions(+), 652 deletions(-)