When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.

Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Fixes: d180e0a1be6c ("Drivers: hv: Create debugfs file with hyper-v balloon usage information")
Cc: stable <stable@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20230202140918.2289522-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull networking updates from Paolo Abeni:
 "Core:

   - Allow live renaming when an interface is up

   - Add retpoline wrappers for tc, improving considerably the
     performances of complex queue discipline configurations

   - Add inet drop monitor support

   - A few GRO performance improvements

   - Add infrastructure for atomic dev stats, addressing long standing
     data races

   - De-duplicate common code between OVS and conntrack offloading
     infrastructure

   - A bunch of UBSAN_BOUNDS/FORTIFY_SOURCE improvements

   - Netfilter: introduce packet parser for tunneled packets

   - Replace IPVS timer-based estimators with kthreads to scale up the
     workload with the number of available CPUs

   - Add the helper support for connection-tracking OVS offload

  BPF:

   - Support for user defined BPF objects: the use case is to allocate
     own objects, build own object hierarchies and use the building
     blocks to build own data structures flexibly, for example, linked
     lists in BPF

   - Make cgroup local storage available to non-cgroup attached BPF
     programs

   - Avoid unnecessary deadlock detection and failures wrt BPF task
     storage helpers

   - A relevant bunch of BPF verifier fixes and improvements

   - Veristat tool improvements to support custom filtering, sorting,
     and replay of results

   - Add LLVM disassembler as default library for dumping JITed code

   - Lots of new BPF documentation for various BPF maps

   - Add bpf_rcu_read_{,un}lock() support for sleepable programs

   - Add RCU grace period chaining to BPF to wait for the completion of
     access from both sleepable and non-sleepable BPF programs

   - Add support storing struct task_struct objects as kptrs in maps

   - Improve helper UAPI by explicitly defining BPF_FUNC_xxx integer
     values

   - Add libbpf *_opts API-variants for bpf_*_get_fd_by_id() functions

  Protocols:

   - TCP: implement Protective Load Balancing across switch links

   - TCP: allow dynamically disabling TCP-MD5 static key, reverting back
     to fast[er]-path

   - UDP: Introduce optional per-netns hash lookup table

   - IPv6: simplify and cleanup sockets disposal

   - Netlink: support different type policies for each generic netlink
     operation

   - MPTCP: add MSG_FASTOPEN and FastOpen listener side support

   - MPTCP: add netlink notification support for listener sockets events

   - SCTP: add VRF support, allowing sctp sockets binding to VRF devices

   - Add bridging MAC Authentication Bypass (MAB) support

   - Extensions for Ethernet VPN bridging implementation to better
     support multicast scenarios

   - More work for Wi-Fi 7 support, comprising conversion of all the
     existing drivers to internal TX queue usage

   - IPSec: introduce a new offload type (packet offload) allowing
     complete header processing and crypto offloading

   - IPSec: extended ack support for more descriptive XFRM error
     reporting

   - RXRPC: increase SACK table size and move processing into a
     per-local endpoint kernel thread, reducing considerably the
     required locking

   - IEEE 802154: synchronous send frame and extended filtering support,
     initial support for scanning available 15.4 networks

   - Tun: bump the link speed from 10Mbps to 10Gbps

   - Tun/VirtioNet: implement UDP segmentation offload support

  Driver API:

   - PHY/SFP: improve power level switching between standard level 1 and
     the higher power levels

   - New API for netdev <-> devlink_port linkage

   - PTP: convert existing drivers to new frequency adjustment
     implementation

   - DSA: add support for rx offloading

   - Autoload DSA tagging driver when dynamically changing protocol

   - Add new PCP and APPTRUST attributes to Data Center Bridging

   - Add configuration support for 800Gbps link speed

   - Add devlink port function attribute to enable/disable RoCE and
     migratable

   - Extend devlink-rate to support strict prioriry and weighted fair
     queuing

   - Add devlink support to directly reading from region memory

   - New device tree helper to fetch MAC address from nvmem

   - New big TCP helper to simplify temporary header stripping

  New hardware / drivers:

   - Ethernet:
      - Marvel Octeon CNF95N and CN10KB Ethernet Switches
      - Marvel Prestera AC5X Ethernet Switch
      - WangXun 10 Gigabit NIC
      - Motorcomm yt8521 Gigabit Ethernet
      - Microchip ksz9563 Gigabit Ethernet Switch
      - Microsoft Azure Network Adapter
      - Linux Automation 10Base-T1L adapter

   - PHY:
      - Aquantia AQR112 and AQR412
      - Motorcomm YT8531S

   - PTP:
      - Orolia ART-CARD

   - WiFi:
      - MediaTek Wi-Fi 7 (802.11be) devices
      - RealTek rtw8821cu, rtw8822bu, rtw8822cu and rtw8723du USB
        devices

   - Bluetooth:
      - Broadcom BCM4377/4378/4387 Bluetooth chipsets
      - Realtek RTL8852BE and RTL8723DS
      - Cypress.CYW4373A0 WiFi + Bluetooth combo device

  Drivers:

   - CAN:
      - gs_usb: bus error reporting support
      - kvaser_usb: listen only and bus error reporting support

   - Ethernet NICs:
      - Intel (100G):
         - extend action skbedit to RX queue mapping
         - implement devlink-rate support
         - support direct read from memory
      - nVidia/Mellanox (mlx5):
         - SW steering improvements, increasing rules update rate
         - Support for enhanced events compression
         - extend H/W offload packet manipulation capabilities
         - implement IPSec packet offload mode
      - nVidia/Mellanox (mlx4):
         - better big TCP support
      - Netronome Ethernet NICs (nfp):
         - IPsec offload support
         - add support for multicast filter
      - Broadcom:
         - RSS and PTP support improvements
      - AMD/SolarFlare:
         - netlink extened ack improvements
         - add basic flower matches to offload, and related stats
      - Virtual NICs:
         - ibmvnic: introduce affinity hint support
      - small / embedded:
         - FreeScale fec: add initial XDP support
         - Marvel mv643xx_eth: support MII/GMII/RGMII modes for Kirkwood
         - TI am65-cpsw: add suspend/resume support
         - Mediatek MT7986: add RX wireless wthernet dispatch support
         - Realtek 8169: enable GRO software interrupt coalescing per
           default

   - Ethernet high-speed switches:
      - Microchip (sparx5):
         - add support for Sparx5 TC/flower H/W offload via VCAP
      - Mellanox mlxsw:
         - add 802.1X and MAC Authentication Bypass offload support
         - add ip6gre support

   - Embedded Ethernet switches:
      - Mediatek (mtk_eth_soc):
         - improve PCS implementation, add DSA untag support
         - enable flow offload support
      - Renesas:
         - add rswitch R-Car Gen4 gPTP support
      - Microchip (lan966x):
         - add full XDP support
         - add TC H/W offload via VCAP
         - enable PTP on bridge interfaces
      - Microchip (ksz8):
         - add MTU support for KSZ8 series

   - Qualcomm 802.11ax WiFi (ath11k):
      - support configuring channel dwell time during scan

   - MediaTek WiFi (mt76):
      - enable Wireless Ethernet Dispatch (WED) offload support
      - add ack signal support
      - enable coredump support
      - remain_on_channel support

   - Intel WiFi (iwlwifi):
      - enable Wi-Fi 7 Extremely High Throughput (EHT) PHY capabilities
      - 320 MHz channels support

   - RealTek WiFi (rtw89):
      - new dynamic header firmware format support
      - wake-over-WLAN support"

* tag 'net-next-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2002 commits)
  ipvs: fix type warning in do_div() on 32 bit
  net: lan966x: Remove a useless test in lan966x_ptp_add_trap()
  net: ipa: add IPA v4.7 support
  dt-bindings: net: qcom,ipa: Add SM6350 compatible
  bnxt: Use generic HBH removal helper in tx path
  IPv6/GRO: generic helper to remove temporary HBH/jumbo header in driver
  selftests: forwarding: Add bridge MDB test
  selftests: forwarding: Rename bridge_mdb test
  bridge: mcast: Support replacement of MDB port group entries
  bridge: mcast: Allow user space to specify MDB entry routing protocol
  bridge: mcast: Allow user space to add (*, G) with a source list and filter mode
  bridge: mcast: Add support for (*, G) with a source list and filter mode
  bridge: mcast: Avoid arming group timer when (S, G) corresponds to a source
  bridge: mcast: Add a flag for user installed source entries
  bridge: mcast: Expose __br_multicast_del_group_src()
  bridge: mcast: Expose br_multicast_new_group_src()
  bridge: mcast: Add a centralized error path
  bridge: mcast: Place netlink policy before validation functions
  bridge: mcast: Split (*, G) and (S, G) addition into different functions
  bridge: mcast: Do not derive entry type from its filter mode
  ...

Pull ACPI and PNP updates from Rafael Wysocki:
 "These include new code (for instance, support for the FFH address
  space type and support for new firmware data structures in ACPICA),
  some new quirks (mostly related to backlight handling and I2C
  enumeration), a number of fixes and a fair amount of cleanups all
  over.

  Specifics:

   - Update the ACPICA code in the kernel to the 20221020 upstream
     version and fix a couple of issues in it:
      - Make acpi_ex_load_op() match upstream implementation (Rafael
        Wysocki)
      - Add support for loong_arch-specific APICs in MADT (Huacai Chen)
      - Add support for fixed PCIe wake event (Huacai Chen)
      - Add EBDA pointer sanity checks (Vit Kabele)
      - Avoid accessing VGA memory when EBDA < 1KiB (Vit Kabele)
      - Add CCEL table support to both compiler/disassembler (Kuppuswamy
        Sathyanarayanan)
      - Add a couple of new UUIDs to the known UUID list (Bob Moore)
      - Add support for FFH Opregion special context data (Sudeep
        Holla)
      - Improve warning message for "invalid ACPI name" (Bob Moore)
      - Add support for CXL 3.0 structures (CXIMS & RDPAS) in the CEDT
        table (Alison Schofield)
      - Prepare IORT support for revision E.e (Robin Murphy)
      - Finish support for the CDAT table (Bob Moore)
      - Fix error code path in acpi_ds_call_control_method() (Rafael
        Wysocki)
      - Fix use-after-free in acpi_ut_copy_ipackage_to_ipackage() (Li
        Zetao)
      - Update the version of the ACPICA code in the kernel (Bob Moore)

   - Use ZERO_PAGE(0) instead of empty_zero_page in the ACPI device
     enumeration code (Giulio Benetti)

   - Change the return type of the ACPI driver remove callback to void
     and update its users accordingly (Dawei Li)

   - Add general support for FFH address space type and implement the
     low- level part of it for ARM64 (Sudeep Holla)

   - Fix stale comments in the ACPI tables parsing code and make it
     print more messages related to MADT (Hanjun Guo, Huacai Chen)

   - Replace invocations of generic library functions with more kernel-
     specific counterparts in the ACPI sysfs interface (Christophe
     JAILLET, Xu Panda)

   - Print full name paths of ACPI power resource objects during
     enumeration (Kane Chen)

   - Eliminate a compiler warning regarding a missing function prototype
     in the ACPI power management code (Sudeep Holla)

   - Fix and clean up the ACPI processor driver (Rafael Wysocki, Li
     Zhong, Colin Ian King, Sudeep Holla)

   - Add quirk for the HP Pavilion Gaming 15-cx0041ur to the ACPI EC
     driver (Mia Kanashi)

   - Add some mew ACPI backlight handling quirks and update some
     existing ones (Hans de Goede)

   - Make the ACPI backlight driver prefer the native backlight control
     over vendor backlight control when possible (Hans de Goede)

   - Drop unsetting ACPI APEI driver data on remove (Uwe Kleine-König)

   - Use xchg_release() instead of cmpxchg() for updating new GHES cache
     slots (Ard Biesheuvel)

   - Clean up the ACPI APEI code (Sudeep Holla, Christophe JAILLET, Jay
     Lu)

   - Add new I2C device enumeration quirks for Medion Lifetab S10346 and
     Lenovo Yoga Tab 3 Pro (YT3-X90F) (Hans de Goede)

   - Make the ACPI battery driver notify user space about adding new
     battery hooks and removing the existing ones (Armin Wolf)

   - Modify the pfr_update and pfr_telemetry drivers to use ACPI_FREE()
     for freeing acpi_object structures to help diagnostics (Wang
     ShaoBo)

   - Make the ACPI fan driver use sysfs_emit_at() in its sysfs interface
     code (ye xingchen)

   - Fix the _FIF package extraction failure handling in the ACPI fan
     driver (Hanjun Guo)

   - Fix the PCC mailbox handling error code path (Huisong Li)

   - Avoid using PCC Opregions if there is no platform interrupt
     allocated for this purpose (Huisong Li)

   - Use sysfs_emit() instead of scnprintf() in the ACPI PAD driver and
     CPPC library (ye xingchen)

   - Fix some kernel-doc issues in the ACPI GSI processing code
     (Xiongfeng Wang)

   - Fix name memory leak in pnp_alloc_dev() (Yang Yingliang)

   - Do not disable PNP devices on suspend when they cannot be
     re-enabled on resume (Hans de Goede)

   - Clean up the ACPI thermal driver a bit (Rafael Wysocki)"

* tag 'acpi-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (67 commits)
  ACPI: x86: Add skip i2c clients quirk for Medion Lifetab S10346
  ACPI: APEI: EINJ: Refactor available_error_type_show()
  ACPI: APEI: EINJ: Fix formatting errors
  ACPI: processor: perflib: Adjust acpi_processor_notify_smm() return value
  ACPI: processor: perflib: Rearrange acpi_processor_notify_smm()
  ACPI: processor: perflib: Rearrange unregistration routine
  ACPI: processor: perflib: Drop redundant parentheses
  ACPI: processor: perflib: Adjust white space
  ACPI: processor: idle: Drop unnecessary statements and parens
  ACPI: thermal: Adjust critical.flags.valid check
  ACPI: fan: Convert to use sysfs_emit_at() API
  ACPICA: Fix use-after-free in acpi_ut_copy_ipackage_to_ipackage()
  ACPI: battery: Call power_supply_changed() when adding hooks
  ACPI: use sysfs_emit() instead of scnprintf()
  ACPI: x86: Add skip i2c clients quirk for Lenovo Yoga Tab 3 Pro (YT3-X90F)
  ACPI: APEI: Remove a useless include
  PNP: Do not disable devices on suspend when they cannot be re-enabled on resume
  ACPI: processor: Silence missing prototype warnings
  ACPI: processor_idle: Silence missing prototype warnings
  ACPI: PM: Silence missing prototype warning
  ...

Pull irq updates from Thomas Gleixner:
 "Updates for the interrupt core and driver subsystem:

  The bulk is the rework of the MSI subsystem to support per device MSI
  interrupt domains. This solves conceptual problems of the current
  PCI/MSI design which are in the way of providing support for
  PCI/MSI[-X] and the upcoming PCI/IMS mechanism on the same device.

  IMS (Interrupt Message Store] is a new specification which allows
  device manufactures to provide implementation defined storage for MSI
  messages (as opposed to PCI/MSI and PCI/MSI-X that has a specified
  message store which is uniform accross all devices). The PCI/MSI[-X]
  uniformity allowed us to get away with "global" PCI/MSI domains.

  IMS not only allows to overcome the size limitations of the MSI-X
  table, but also gives the device manufacturer the freedom to store the
  message in arbitrary places, even in host memory which is shared with
  the device.

  There have been several attempts to glue this into the current MSI
  code, but after lengthy discussions it turned out that there is a
  fundamental design problem in the current PCI/MSI-X implementation.
  This needs some historical background.

  When PCI/MSI[-X] support was added around 2003, interrupt management
  was completely different from what we have today in the actively
  developed architectures. Interrupt management was completely
  architecture specific and while there were attempts to create common
  infrastructure the commonalities were rudimentary and just providing
  shared data structures and interfaces so that drivers could be written
  in an architecture agnostic way.

  The initial PCI/MSI[-X] support obviously plugged into this model
  which resulted in some basic shared infrastructure in the PCI core
  code for setting up MSI descriptors, which are a pure software
  construct for holding data relevant for a particular MSI interrupt,
  but the actual association to Linux interrupts was completely
  architecture specific. This model is still supported today to keep
  museum architectures and notorious stragglers alive.

  In 2013 Intel tried to add support for hot-pluggable IO/APICs to the
  kernel, which was creating yet another architecture specific mechanism
  and resulted in an unholy mess on top of the existing horrors of x86
  interrupt handling. The x86 interrupt management code was already an
  incomprehensible maze of indirections between the CPU vector
  management, interrupt remapping and the actual IO/APIC and PCI/MSI[-X]
  implementation.

  At roughly the same time ARM struggled with the ever growing SoC
  specific extensions which were glued on top of the architected GIC
  interrupt controller.

  This resulted in a fundamental redesign of interrupt management and
  provided the today prevailing concept of hierarchical interrupt
  domains. This allowed to disentangle the interactions between x86
  vector domain and interrupt remapping and also allowed ARM to handle
  the zoo of SoC specific interrupt components in a sane way.

  The concept of hierarchical interrupt domains aims to encapsulate the
  functionality of particular IP blocks which are involved in interrupt
  delivery so that they become extensible and pluggable. The X86
  encapsulation looks like this:

                                            |--- device 1
     [Vector]---[Remapping]---[PCI/MSI]--|...
                                            |--- device N

  where the remapping domain is an optional component and in case that
  it is not available the PCI/MSI[-X] domains have the vector domain as
  their parent. This reduced the required interaction between the
  domains pretty much to the initialization phase where it is obviously
  required to establish the proper parent relation ship in the
  components of the hierarchy.

  While in most cases the model is strictly representing the chain of IP
  blocks and abstracting them so they can be plugged together to form a
  hierarchy, the design stopped short on PCI/MSI[-X]. Looking at the
  hardware it's clear that the actual PCI/MSI[-X] interrupt controller
  is not a global entity, but strict a per PCI device entity.

  Here we took a short cut on the hierarchical model and went for the
  easy solution of providing "global" PCI/MSI domains which was possible
  because the PCI/MSI[-X] handling is uniform across the devices. This
  also allowed to keep the existing PCI/MSI[-X] infrastructure mostly
  unchanged which in turn made it simple to keep the existing
  architecture specific management alive.

  A similar problem was created in the ARM world with support for IP
  block specific message storage. Instead of going all the way to stack
  a IP block specific domain on top of the generic MSI domain this ended
  in a construct which provides a "global" platform MSI domain which
  allows overriding the irq_write_msi_msg() callback per allocation.

  In course of the lengthy discussions we identified other abuse of the
  MSI infrastructure in wireless drivers, NTB etc. where support for
  implementation specific message storage was just mindlessly glued into
  the existing infrastructure. Some of this just works by chance on
  particular platforms but will fail in hard to diagnose ways when the
  driver is used on platforms where the underlying MSI interrupt
  management code does not expect the creative abuse.

  Another shortcoming of today's PCI/MSI-X support is the inability to
  allocate or free individual vectors after the initial enablement of
  MSI-X. This results in an works by chance implementation of VFIO (PCI
  pass-through) where interrupts on the host side are not set up upfront
  to avoid resource exhaustion. They are expanded at run-time when the
  guest actually tries to use them. The way how this is implemented is
  that the host disables MSI-X and then re-enables it with a larger
  number of vectors again. That works by chance because most device
  drivers set up all interrupts before the device actually will utilize
  them. But that's not universally true because some drivers allocate a
  large enough number of vectors but do not utilize them until it's
  actually required, e.g. for acceleration support. But at that point
  other interrupts of the device might be in active use and the MSI-X
  disable/enable dance can just result in losing interrupts and
  therefore hard to diagnose subtle problems.

  Last but not least the "global" PCI/MSI-X domain approach prevents to
  utilize PCI/MSI[-X] and PCI/IMS on the same device due to the fact
  that IMS is not longer providing a uniform storage and configuration
  model.

  The solution to this is to implement the missing step and switch from
  global PCI/MSI domains to per device PCI/MSI domains. The resulting
  hierarchy then looks like this:

                              |--- [PCI/MSI] device 1
     [Vector]---[Remapping]---|...
                              |--- [PCI/MSI] device N

  which in turn allows to provide support for multiple domains per
  device:

                              |--- [PCI/MSI] device 1
                              |--- [PCI/IMS] device 1
     [Vector]---[Remapping]---|...
                              |--- [PCI/MSI] device N
                              |--- [PCI/IMS] device N

  This work converts the MSI and PCI/MSI core and the x86 interrupt
  domains to the new model, provides new interfaces for post-enable
  allocation/free of MSI-X interrupts and the base framework for
  PCI/IMS. PCI/IMS has been verified with the work in progress IDXD
  driver.

  There is work in progress to convert ARM over which will replace the
  platform MSI train-wreck. The cleanup of VFIO, NTB and other creative
  "solutions" are in the works as well.

  Drivers:

   - Updates for the LoongArch interrupt chip drivers

   - Support for MTK CIRQv2

   - The usual small fixes and updates all over the place"

* tag 'irq-core-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (134 commits)
  irqchip/ti-sci-inta: Fix kernel doc
  irqchip/gic-v2m: Mark a few functions __init
  irqchip/gic-v2m: Include arm-gic-common.h
  irqchip/irq-mvebu-icu: Fix works by chance pointer assignment
  iommu/amd: Enable PCI/IMS
  iommu/vt-d: Enable PCI/IMS
  x86/apic/msi: Enable PCI/IMS
  PCI/MSI: Provide pci_ims_alloc/free_irq()
  PCI/MSI: Provide IMS (Interrupt Message Store) support
  genirq/msi: Provide constants for PCI/IMS support
  x86/apic/msi: Enable MSI_FLAG_PCI_MSIX_ALLOC_DYN
  PCI/MSI: Provide post-enable dynamic allocation interfaces for MSI-X
  PCI/MSI: Provide prepare_desc() MSI domain op
  PCI/MSI: Split MSI-X descriptor setup
  genirq/msi: Provide MSI_FLAG_MSIX_ALLOC_DYN
  genirq/msi: Provide msi_domain_alloc_irq_at()
  genirq/msi: Provide msi_domain_ops:: Prepare_desc()
  genirq/msi: Provide msi_desc:: Msi_data
  genirq/msi: Provide struct msi_map
  x86/apic/msi: Remove arch_create_remap_msi_irq_domain()
  ...

Merge ACPI changes related to device enumeration, device object
managenet, operation region handling, table parsing and sysfs
interface:

 - Use ZERO_PAGE(0) instead of empty_zero_page in the ACPI device
   enumeration code (Giulio Benetti).

 - Change the return type of the ACPI driver remove callback to void and
   update its users accordingly (Dawei Li).

 - Add general support for FFH address space type and implement the low-
   level part of it for ARM64 (Sudeep Holla).

 - Fix stale comments in the ACPI tables parsing code and make it print
   more messages related to MADT (Hanjun Guo, Huacai Chen).

 - Replace invocations of generic library functions with more kernel-
   specific counterparts in the ACPI sysfs interface (Christophe JAILLET,
   Xu Panda).

* acpi-scan:
  ACPI: scan: substitute empty_zero_page with helper ZERO_PAGE(0)

* acpi-bus:
  ACPI: FFH: Silence missing prototype warnings
  ACPI: make remove callback of ACPI driver void
  ACPI: bus: Fix the _OSC capability check for FFH OpRegion
  arm64: Add architecture specific ACPI FFH Opregion callbacks
  ACPI: Implement a generic FFH Opregion handler

* acpi-tables:
  ACPI: tables: Fix the stale comments for acpi_locate_initial_tables()
  ACPI: tables: Print CORE_PIC information when MADT is parsed

* acpi-sysfs:
  ACPI: sysfs: use sysfs_emit() to instead of scnprintf()
  ACPI: sysfs: Use kstrtobool() instead of strtobool()

tools/lib/bpf/ringbuf.c
  927cbb478adf ("libbpf: Handle size overflow for ringbuf mmap")
  b486d19a0ab0 ("libbpf: checkpatch: Fixed code alignments in ringbuf.c")
https://lore.kernel.org/all/20221121122707.44d1446a@canb.auug.org.au/

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Currently Hyper-V guests are among the most relevant users of the panic
infrastructure, like panic notifiers, kmsg dumpers, etc. The reasons rely
both in cleaning-up procedures (closing hypervisor <-> guest connection,
disabling some paravirtualized timer) as well as to data collection
(sending panic information to the hypervisor) and framebuffer management.

The thing is: some notifiers are related to others, ordering matters, some
functionalities are duplicated and there are lots of conditionals behind
sending panic information to the hypervisor. As part of an effort to
clean-up the panic notifiers mechanism and better document things, we
hereby address some of the issues/complexities of Hyper-V panic handling
through the following changes:

(a) We have die and panic notifiers on vmbus_drv.c and both have goals of
sending panic information to the hypervisor, though the panic notifier is
also responsible for a cleaning-up procedure.

This commit clears the code by splitting the panic notifier in two, one
for closing the vmbus connection whereas the other is only for sending
panic info to hypervisor. With that, it was possible to merge the die and
panic notifiers in a single/well-documented function, and clear some
conditional complexities on sending such information to the hypervisor.

(b) There is a Hyper-V framebuffer panic notifier, which relies in doing
a vmbus operation that demands a valid connection. So, we must order this
notifier with the panic notifier from vmbus_drv.c, to guarantee that the
framebuffer code executes before the vmbus connection is unloaded.

Also, this commit removes a useless header.

Although there is code rework and re-ordering, we expect that this change
has no functional regressions but instead optimize the path and increase
panic reliability on Hyper-V. This was tested on Hyper-V with success.

Cc: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Tianyu Lan <Tianyu.Lan@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Fabio A M Martins <fabiomirmar@gmail.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220819221731.480795-11-gpiccoli@igalia.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

The Hyper-V framebuffer code registers a panic notifier in order
to try updating its fbdev if the kernel crashed. The notifier
callback is straightforward, but it calls the vmbus_sendpacket()
routine eventually, and such function takes a spinlock for the
ring buffer operations.

Panic path runs in atomic context, with local interrupts and
preemption disabled, and all secondary CPUs shutdown. That said,
taking a spinlock might cause a lockup if a secondary CPU was
disabled with such lock taken. Fix it here by checking if the
ring buffer spinlock is busy on Hyper-V framebuffer panic notifier;
if so, bail-out avoiding the potential lockup scenario.

Cc: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Tianyu Lan <Tianyu.Lan@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Tested-by: Fabio A M Martins <fabiomirmar@gmail.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220819221731.480795-10-gpiccoli@igalia.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

Newer versions of Hyper-V allow reporting unused guest pages in chunks
smaller than 2 Mbytes.  Using smaller chunks allows reporting more
unused guest pages, but with increased overhead in the finding the
small chunks.  To make this tradeoff configurable, use the existing
page_reporting_order module parameter to control the reporting order.
Drop and refine checks that restricted the minimun page reporting order
to 2Mbytes size pages. Add appropriate checks to make sure the
underlying Hyper-V versions support cold discard hints of any order
(and not just starting from 9)

Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1664517699-1085-3-git-send-email-shradhagupta@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

For bus-based driver, device removal is implemented as:
1 device_remove()->
2   bus->remove()->
3     driver->remove()

Driver core needs no inform from callee(bus driver) about the
result of remove callback. In that case, commit fc7a6209d571
("bus: Make remove callback return void") forces bus_type::remove
be void-returned.

Now we have the situation that both 1 & 2 of calling chain are
void-returned, so it does not make much sense for 3(driver->remove)
to return non-void to its caller.

So the basic idea behind this change is making remove() callback of
any bus-based driver to be void-returned.

This change, for itself, is for device drivers based on acpi-bus.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Lee Jones <lee@kernel.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dawei Li <set_pte_at@outlook.com>
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>  # for drivers/platform/surface/*
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>