the reason is to avoid a delay caused by the synchronize_rcu() call in
kern_umount() when the mqueue mount is freed.

the code:

    #define _GNU_SOURCE
    #include <sched.h>
    #include <error.h>
    #include <errno.h>
    #include <stdlib.h>

    int main()
    {
        int i;

        for (i = 0; i < 1000; i++)
            if (unshare(CLONE_NEWIPC) < 0)
                error(EXIT_FAILURE, errno, "unshare");
    }

goes from

	Command being timed: "./ipc-namespace"
	User time (seconds): 0.00
	System time (seconds): 0.06
	Percent of CPU this job got: 0%
	Elapsed (wall clock) time (h:mm:ss or m:ss): 0:08.05

to

	Command being timed: "./ipc-namespace"
	User time (seconds): 0.00
	System time (seconds): 0.02
	Percent of CPU this job got: 96%
	Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.03
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Link: http://lkml.kernel.org/r/20200225145419.527994-1-gscrivan@redhat.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Sparse reports a warning at freeque()

warning: context imbalance in freeque() - unexpected unlock

The root cause is the missing annotation at freeque()

Add the missing __releases(RCU) annotation
Add the missing __releases(&msq->q_perm) annotation
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Lu Shuaibing <shuaibinglu@126.com>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Link: http://lkml.kernel.org/r/20200403160505.2832-2-jbi.octave@gmail.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

'Idle page tracking' users can pass random pfn that might be mapped to an
offline page.  To avoid accessing such pages, this commit modifies the
'page_idle_get_page()' to use 'pfn_to_online_page()' instead of
'pfn_valid()' and 'pfn_to_page()' combination, so that the pfn mapped to
an offline page can be skipped.
Reported-by: David Hildenbrand <david@redhat.com>
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Link: http://lkml.kernel.org/r/20200605092502.18018-2-sjpark@amazon.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull char/misc driver updates from Greg KH:
 "Here is the large set of char/misc driver patches for 5.8-rc1

  Included in here are:

   - habanalabs driver updates, loads

   - mhi bus driver updates

   - extcon driver updates

   - clk driver updates (approved by the clock maintainer)

   - firmware driver updates

   - fpga driver updates

   - gnss driver updates

   - coresight driver updates

   - interconnect driver updates

   - parport driver updates (it's still alive!)

   - nvmem driver updates

   - soundwire driver updates

   - visorbus driver updates

   - w1 driver updates

   - various misc driver updates

  In short, loads of different driver subsystem updates along with the
  drivers as well.

  All have been in linux-next for a while with no reported issues"

* tag 'char-misc-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (233 commits)
  habanalabs: correctly cast u64 to void*
  habanalabs: initialize variable to default value
  extcon: arizona: Fix runtime PM imbalance on error
  extcon: max14577: Add proper dt-compatible strings
  extcon: adc-jack: Fix an error handling path in 'adc_jack_probe()'
  extcon: remove redundant assignment to variable idx
  w1: omap-hdq: print dev_err if irq flags are not cleared
  w1: omap-hdq: fix interrupt handling which did show spurious timeouts
  w1: omap-hdq: fix return value to be -1 if there is a timeout
  w1: omap-hdq: cleanup to add missing newline for some dev_dbg
  /dev/mem: Revoke mappings when a driver claims the region
  misc: xilinx-sdfec: convert get_user_pages() --> pin_user_pages()
  misc: xilinx-sdfec: cleanup return value in xsdfec_table_write()
  misc: xilinx-sdfec: improve get_user_pages_fast() error handling
  nvmem: qfprom: remove incorrect write support
  habanalabs: handle MMU cache invalidation timeout
  habanalabs: don't allow hard reset with open processes
  habanalabs: GAUDI does not support soft-reset
  habanalabs: add print for soft reset due to event
  habanalabs: improve MMU cache invalidation code
  ...

Pull driver core updates from Greg KH:
 "Here is the set of driver core patches for 5.8-rc1.

  Not all that huge this release, just a number of small fixes and
  updates:

   - software node fixes

   - kobject now sends KOBJ_REMOVE when it is removed from sysfs, not
     when it is removed from memory (which could come much later)

   - device link additions and fixes based on testing on more devices

   - firmware core cleanups

   - other minor changes, full details in the shortlog

  All have been in linux-next for a while with no reported issues"

* tag 'driver-core-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (23 commits)
  driver core: Update device link status correctly for SYNC_STATE_ONLY links
  firmware_loader: change enum fw_opt to u32
  software node: implement software_node_unregister()
  kobject: send KOBJ_REMOVE uevent when the object is removed from sysfs
  driver core: Remove unnecessary is_fwnode_dev variable in device_add()
  drivers property: When no children in primary, try secondary
  driver core: platform: Fix spelling errors in platform.c
  driver core: Remove check in driver_deferred_probe_force_trigger()
  of: platform: Batch fwnode parsing when adding all top level devices
  driver core: fw_devlink: Add support for batching fwnode parsing
  driver core: Look for waiting consumers only for a fwnode's primary device
  driver core: Move code to the right part of the file
  Revert "Revert "driver core: Set fw_devlink to "permissive" behavior by default""
  drivers: base: Fix NULL pointer exception in __platform_driver_probe() if a driver developer is foolish
  firmware_loader: move fw_fallback_config to a private kernel symbol namespace
  driver core: Add missing '\n' in log messages
  driver/base/soc: Use kobj_to_dev() API
  Add documentation on meaning of -EPROBE_DEFER
  driver core: platform: remove redundant assignment to variable ret
  debugfs: Use the correct style for SPDX License Identifier
  ...

Pull staging/IIO driver updates from Greg KH:
 "Here is the large set of staging and IIO driver changes for 5.8-rc1

  Nothing major, but a lot of new IIO drivers are included in here,
  along with other core iio cleanups and changes.

  On the staging driver front, again, nothing noticable. No new
  deletions or additions, just a ton of tiny cleanups all over the tree
  done by a lot of different people. Most coding style, but many actual
  real fixes and cleanups that are nice to see.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'staging-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (618 commits)
  staging: rtl8723bs: Use common packet header constants
  staging: sm750fb: Add names to proc_setBLANK args
  staging: most: usb: init return value in default path of switch/case expression
  staging: vchiq: Get rid of VCHIQ_SERVICE_OPENEND callback reason
  staging: vchiq: move vchiq_release_message() into vchiq
  staging: vchi: Get rid of C++ guards
  staging: vchi: Get rid of not implemented function declarations
  staging: vchi: Get rid of vchiq_status_to_vchi()
  staging: vchi: Get rid of vchi_service_set_option()
  staging: vchi: Merge vchi_msg_queue() into vchi_queue_kernel_message()
  staging: vchiq: Move copy callback handling into vchiq
  staging: vchi: Get rid of vchi_queue_user_message()
  staging: vchi: Get rid of vchi_service_destroy()
  staging: most: usb: use function sysfs_streq
  staging: most: usb: add missing put_device calls
  staging: most: usb: use correct error codes
  staging: most: usb: replace code to calculate array index
  staging: most: usb: don't use error path to exit function on success
  staging: most: usb: move allocation of URB out of critical section
  staging: most: usb: return 0 instead of variable
  ...

Pull tty/serial driver updates from Greg KH:
 "Here is the tty and serial driver updates for 5.8-rc1

  Nothing huge at all, just a lot of little serial driver fixes, updates
  for new devices and features, and other small things. Full details are
  in the shortlog.

  All of these have been in linux-next with no issues for a while"

* tag 'tty-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (67 commits)
  tty: serial: qcom_geni_serial: Add 51.2MHz frequency support
  tty: serial: imx: clear Ageing Timer Interrupt in handler
  serial: 8250_fintek: Add F81966 Support
  sc16is7xx: Add flag to activate IrDA mode
  dt-bindings: sc16is7xx: Add flag to activate IrDA mode
  serial: 8250: Support rs485 bus termination GPIO
  serial: 8520_port: Fix function param documentation
  dt-bindings: serial: Add binding for rs485 bus termination GPIO
  vt: keyboard: avoid signed integer overflow in k_ascii
  serial: 8250: Enable 16550A variants by default on non-x86
  tty: hvc_console, fix crashes on parallel open/close
  serial: imx: Initialize lock for non-registered console
  sc16is7xx: Read the LSR register for basic device presence check
  sc16is7xx: Allow sharing the IRQ line
  sc16is7xx: Use threaded IRQ
  sc16is7xx: Always use falling edge IRQ
  tty: n_gsm: Fix bogus i++ in gsm_data_kick
  tty: n_gsm: Remove unnecessary test in gsm_print_packet()
  serial: stm32: add no_console_suspend support
  tty: serial: fsl_lpuart: Use __maybe_unused instead of #if CONFIG_PM_SLEEP
  ...

Pull USB/PHY driver updates from Greg KH:
 "Here are the large set of USB and PHY driver updates for 5.8-rc1.

  Nothing huge, just lots of little things:

   - USB gadget fixes and additions all over the place

   - new PHY drivers

   - PHY driver fixes and updates

   - XHCI driver updates

   - musb driver updates

   - more USB-serial driver ids added

   - various USB quirks added

   - thunderbolt minor updates and fixes

   - typec updates and additions

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'usb-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (245 commits)
  usb: dwc3: meson-g12a: fix USB2 PHY initialization on G12A and A1 SoCs
  usb: dwc3: meson-g12a: fix error path when fetching the reset line fails
  Revert "dt-bindings: usb: qcom,dwc3: Convert USB DWC3 bindings"
  Revert "dt-bindings: usb: qcom,dwc3: Add compatible for SC7180"
  Revert "dt-bindings: usb: qcom,dwc3: Introduce interconnect properties for Qualcomm DWC3 driver"
  USB: serial: ch341: fix lockup of devices with limited prescaler
  USB: serial: ch341: add basis for quirk detection
  CDC-ACM: heed quirk also in error handling
  USB: serial: option: add Telit LE910C1-EUX compositions
  usb: musb: Fix runtime PM imbalance on error
  usb: musb: jz4740: Prevent lockup when CONFIG_SMP is set
  usb: musb: mediatek: add reset FADDR to zero in reset interrupt handle
  usb: musb: use true for 'use_dma'
  usb: musb: start session in resume for host port
  usb: musb: return -ESHUTDOWN in urb when three-strikes error happened
  USB: serial: qcserial: add DW5816e QDL support
  thunderbolt: Add trivial .shutdown
  usb: dwc3: keystone: Turn on USB3 PHY before controller
  dt-bindings: usb: ti,keystone-dwc3.yaml: Add USB3.0 PHY property
  dt-bindings: usb: convert keystone-usb.txt to YAML
  ...

Pull arch/sh updates from Rich Felker:
 "Fix for arch/sh build regression with newer binutils, removal of SH5,
  fixes for module exports, and misc cleanup"

* tag 'sh-for-5.8' of git://git.libc.org/linux-sh:
  sh: remove sh5 support
  sh: add missing EXPORT_SYMBOL() for __delay
  sh: Convert ins[bwl]/outs[bwl] macros to inline functions
  sh: Convert iounmap() macros to inline functions
  sh: Add missing DECLARE_EXPORT() for __ashiftrt_r4_xx
  sh: configs: Cleanup old Kconfig IO scheduler options
  arch/sh: vmlinux.scr
  sh: Replace CONFIG_MTD_M25P80 with CONFIG_MTD_SPI_NOR in sh7757lcr_defconfig
  sh: sh4a: Bring back tmu3_device early device

Pull Kconfig updates from Masahiro Yamada:

 - allow only 'config', 'comment', 'if' statements inside 'choice' since
   the other statements are not sensible inside 'choice' and should be
   grammatical error

 - support LMC_KEEP env variable for 'make local{yes,mod}config' to
   preserve some CONFIG options

 - deprecate 'make kvmconfig' and 'make xenconfig' in favor of
   'make kvm_guest.config' and 'make xen.config'

 - code cleanups

* tag 'kconfig-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kconfig: announce removal of 'kvmconfig' and 'xenconfig' shorthands
  streamline_config.pl: add LMC_KEEP to preserve some kconfigs
  kconfig: allow only 'config', 'comment', and 'if' inside 'choice'
  kconfig: tests: remove randconfig test for choice in choice
  kconfig: do not assign a variable in the return statement
  kconfig: do not use OR-assignment for zero-cleared structure

Pull Kbuild updates from Masahiro Yamada:

 - fix warnings in 'make clean' for ARCH=um, hexagon, h8300, unicore32

 - ensure to rebuild all objects when the compiler is upgraded

 - exclude system headers from dependency tracking and fixdep processing

 - fix potential bit-size mismatch between the kernel and BPF user-mode
   helper

 - add the new syntax 'userprogs' to build user-space programs for the
   target architecture (the same arch as the kernel)

 - compile user-space sample code under samples/ for the target arch
   instead of the host arch

 - make headers_install fail if a CONFIG option is leaked to user-space

 - sanitize the output format of scripts/checkstack.pl

 - handle ARM 'push' instruction in scripts/checkstack.pl

 - error out before modpost if a module name conflict is found

 - error out when multiple directories are passed to M= because this
   feature is broken for a long time

 - add CONFIG_DEBUG_INFO_COMPRESSED to support compressed debug info

 - a lot of cleanups of modpost

 - dump vmlinux symbols out into vmlinux.symvers, and reuse it in the
   second pass of modpost

 - do not run the second pass of modpost if nothing in modules is
   updated

 - install modules.builtin(.modinfo) by 'make install' as well as by
   'make modules_install' because it is useful even when
   CONFIG_MODULES=n

 - add new command line variables, GZIP, BZIP2, LZOP, LZMA, LZ4, and XZ
   to allow users to use alternatives such as pigz, pbzip2, etc.

* tag 'kbuild-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (96 commits)
  kbuild: add variables for compression tools
  Makefile: install modules.builtin even if CONFIG_MODULES=n
  mksysmap: Fix the mismatch of '.L' symbols in System.map
  kbuild: doc: rename LDFLAGS to KBUILD_LDFLAGS
  modpost: change elf_info->size to size_t
  modpost: remove is_vmlinux() helper
  modpost: strip .o from modname before calling new_module()
  modpost: set have_vmlinux in new_module()
  modpost: remove mod->skip struct member
  modpost: add mod->is_vmlinux struct member
  modpost: remove is_vmlinux() call in check_for_{gpl_usage,unused}()
  modpost: remove mod->is_dot_o struct member
  modpost: move -d option in scripts/Makefile.modpost
  modpost: remove -s option
  modpost: remove get_next_text() and make {grab,release_}file static
  modpost: use read_text_file() and get_line() for reading text files
  modpost: avoid false-positive file open error
  modpost: fix potential mmap'ed file overrun in get_src_version()
  modpost: add read_text_file() and get_line() helpers
  modpost: do not call get_modinfo() for vmlinux(.o)
  ...

Pull dma-mapping helpers from Christoph Hellwig:
 "These were in a separate stable branch so that various media and drm
  trees could pull the in for bug fixes, but looking at linux-next that
  hasn't actually happened yet. Still sending the APIs to you in the
  hope that these bug fixes get picked up for 5.8 in one way or another.

  Summary:

   - add DMA mapping helpers for struct sg_table (Marek Szyprowski)"

* tag 'dma-mapping-5.8-2' of git://git.infradead.org/users/hch/dma-mapping:
  iommu: add generic helper for mapping sgtable objects
  scatterlist: add generic wrappers for iterating over sgtable objects
  dma-mapping: add generic helpers for mapping sgtable objects

Pull dma-mapping updates from Christoph Hellwig:

 - enhance the dma pool to allow atomic allocation on x86 with AMD SEV
   (David Rientjes)

 - two small cleanups (Jason Yan and Peter Collingbourne)

* tag 'dma-mapping-5.8' of git://git.infradead.org/users/hch/dma-mapping:
  dma-contiguous: fix comment for dma_release_from_contiguous
  dma-pool: scale the default DMA coherent pool size with memory capacity
  x86/mm: unencrypted non-blocking DMA allocations use coherent pools
  dma-pool: add pool sizes to debugfs
  dma-direct: atomic allocations must come from atomic coherent pools
  dma-pool: dynamically expanding atomic pools
  dma-pool: add additional coherent pools to map to gfp mask
  dma-remap: separate DMA atomic pools from direct remap code
  dma-debug: make __dma_entry_alloc_check_leak() static

Pull dmi update from Jean Delvare.

* 'dmi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
  firmware/dmi: Report DMI Bios & EC firmware release

Pull PCI updates from Bjorn Helgaas:
 "Enumeration:

   - Program MPS for RCiEP devices (Ashok Raj)

   - Fix pci_register_host_bridge() device_register() error handling
     (Rob Herring)

   - Fix pci_host_bridge struct device release/free handling (Rob
     Herring)

  Resource management:

   - Allow resizing BARs for devices on root bus (Ard Biesheuvel)

  Power management:

   - Reduce Thunderbolt resume time by working around devices that don't
     support DLL Link Active reporting (Mika Westerberg)

   - Work around a Pericom USB controller OHCI/EHCI PME# defect
     (Kai-Heng Feng)

  Virtualization:

   - Add ACS quirk for Intel Root Complex Integrated Endpoints (Ashok
     Raj)

   - Avoid FLR for AMD Starship USB 3.0 (Kevin Buettner)

   - Avoid FLR for AMD Matisse HD Audio & USB 3.0 (Marcos Scriven)

  Error handling:

   - Use only _OSC (not HEST FIRMWARE_FIRST) to determine AER ownership
     (Alexandru Gagniuc, Kuppuswamy Sathyanarayanan)

   - Reduce verbosity by logging only ACPI_NOTIFY_DISCONNECT_RECOVER
     events (Kuppuswamy Sathyanarayanan)

   - Don't enable AER by default in Kconfig (Bjorn Helgaas)

  Peer-to-peer DMA:

   - Add AMD Zen Raven and Renoir Root Ports to whitelist (Alex Deucher)

  ASPM:

   - Allow ASPM on links to PCIe-to-PCI/PCI-X Bridges (Kai-Heng Feng)

  Endpoint framework:

   - Fix DMA channel release in test (Kunihiko Hayashi)

   - Add page size as argument to pci_epc_mem_init() (Lad Prabhakar)

   - Add support to handle multiple base for mapping outbound memory
     (Lad Prabhakar)

  Generic host bridge driver:

   - Support building as module (Rob Herring)

   - Eliminate pci_host_common_probe wrappers (Rob Herring)

  Amlogic Meson PCIe controller driver:

   - Don't use FAST_LINK_MODE to set up link (Marc Zyngier)

  Broadcom STB PCIe controller driver:

   - Disable ASPM L0s if 'aspm-no-l0s' in DT (Jim Quinlan)

   - Fix clk_put() error (Jim Quinlan)

   - Fix window register offset (Jim Quinlan)

   - Assert fundamental reset on initialization (Nicolas Saenz Julienne)

   - Add notify xHCI reset property (Nicolas Saenz Julienne)

   - Add init routine for Raspberry Pi 4 VL805 USB controller (Nicolas
     Saenz Julienne)

   - Sync with Raspberry Pi 4 firmware for VL805 initialization (Nicolas
     Saenz Julienne)

  Cadence PCIe controller driver:

   - Remove "cdns,max-outbound-regions" DT property (replaced by
     "ranges") (Kishon Vijay Abraham I)

   - Read 32-bit (not 16-bit) Vendor ID/Device ID property from DT
     (Kishon Vijay Abraham I)

  Marvell Aardvark PCIe controller driver:

   - Improve link training (Marek Behún)

   - Add PHY support (Marek Behún)

   - Add "phys", "max-link-speed", "reset-gpios" to dt-binding (Marek
     Behún)

   - Train link immediately after enabling training to work around
     detection issues with some cards (Pali Rohár)

   - Issue PERST via GPIO to work around detection issues (Pali Rohár)

   - Don't blindly enable ASPM L0s (Pali Rohár)

   - Replace custom macros by standard linux/pci_regs.h macros (Pali
     Rohár)

  Microsoft Hyper-V host bridge driver:

   - Fix probe failure path to release resource (Wei Hu)

   - Retry PCI bus D0 entry on invalid device state for kdump (Wei Hu)

  Renesas R-Car PCIe controller driver:

   - Fix incorrect programming of OB windows (Andrew Murray)

   - Add suspend/resume (Kazufumi Ikeda)

   - Rename pcie-rcar.c to pcie-rcar-host.c (Lad Prabhakar)

   - Add endpoint controller driver (Lad Prabhakar)

   - Fix PCIEPAMR mask calculation (Lad Prabhakar)

   - Add r8a77961 to DT binding (Yoshihiro Shimoda)

  Socionext UniPhier Pro5 controller driver:

   - Add endpoint controller driver (Kunihiko Hayashi)

  Synopsys DesignWare PCIe controller driver:

   - Program outbound ATU upper limit register (Alan Mikhak)

   - Fix inner MSI IRQ domain registration (Marc Zyngier)

  Miscellaneous:

   - Check for platform_get_irq() failure consistently (negative return
     means failure) (Aman Sharma)

   - Fix several runtime PM get/put imbalances (Dinghao Liu)

   - Use flexible-array and struct_size() helpers for code cleanup
     (Gustavo A. R. Silva)

   - Update & fix issues in bridge emulation of PCIe registers (Jon
     Derrick)

   - Add macros for bridge window names (PCI_BRIDGE_IO_WINDOW, etc)
     (Krzysztof Wilczyński)

   - Work around Intel PCH MROMs that have invalid BARs (Xiaochun Lee)"

* tag 'pci-v5.8-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (100 commits)
  PCI: uniphier: Add Socionext UniPhier Pro5 PCIe endpoint controller driver
  PCI: Add ACS quirk for Intel Root Complex Integrated Endpoints
  PCI/DPC: Print IRQ number used by port
  PCI/AER: Use "aer" variable for capability offset
  PCI/AER: Remove redundant dev->aer_cap checks
  PCI/AER: Remove redundant pci_is_pcie() checks
  PCI/AER: Remove HEST/FIRMWARE_FIRST parsing for AER ownership
  PCI: tegra: Fix runtime PM imbalance on error
  PCI: vmd: Filter resource type bits from shadow register
  PCI: tegra194: Fix runtime PM imbalance on error
  dt-bindings: PCI: Add UniPhier PCIe endpoint controller description
  PCI: hv: Use struct_size() helper
  PCI: Rename _DSM constants to align with spec
  PCI: Avoid FLR for AMD Starship USB 3.0
  PCI: Avoid FLR for AMD Matisse HD Audio & USB 3.0
  x86/PCI: Drop unused xen_register_pirq() gsi_override parameter
  PCI: dwc: Use private data pointer of "struct irq_domain" to get pcie_port
  PCI: amlogic: meson: Don't use FAST_LINK_MODE to set up link
  PCI: dwc: Fix inner MSI IRQ domain registration
  PCI: dwc: pci-dra7xx: Use devm_platform_ioremap_resource_byname()
  ...

Fixes coccicheck warning:

  fs/hpfs/buffer.c:56:2-3: Unneeded semicolon
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Signed-off-by: Mikulas Patocka <mikulas@twibright.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull workqueue updates from Tejun Heo:
 "Mostly cleanups and other trivial changes.

  The only interesting change is Sebastian's rcuwait conversion for RT"

* 'for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: use BUILD_BUG_ON() for compile time test instead of WARN_ON()
  workqueue: fix a piece of comment about reserved bits for work flags
  workqueue: remove useless unlock() and lock() in series
  workqueue: void unneeded requeuing the pwq in rescuer thread
  workqueue: Convert the pool::lock and wq_mayday_lock to raw_spinlock_t
  workqueue: Use rcuwait for wq_manager_wait
  workqueue: Remove unnecessary kfree() call in rcu_free_wq()
  workqueue: Fix an use after free in init_rescuer()
  workqueue: Use IS_ERR and PTR_ERR instead of PTR_ERR_OR_ZERO.

Pull cgroup updates from Tejun Heo:
 "Just two patches: one to add system-level cpu.stat to the root cgroup
  for convenience and a trivial comment update"

* 'for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: add cpu.stat file to root cgroup
  cgroup: Remove stale comments

Pull integrity updates from Mimi Zohar:
 "The main changes are extending the TPM 2.0 PCR banks with bank
  specific file hashes, calculating the "boot_aggregate" based on other
  TPM PCR banks, using the default IMA hash algorithm, instead of SHA1,
  as the basis for the cache hash table key, and preventing the mprotect
  syscall to circumvent an IMA mmap appraise policy rule.

   - In preparation for extending TPM 2.0 PCR banks with bank specific
     digests, commit 0b6cf6b9 ("tpm: pass an array of
     tpm_extend_digest structures to tpm_pcr_extend()") modified
     tpm_pcr_extend(). The original SHA1 file digests were
     padded/truncated, before being extended into the other TPM PCR
     banks. This pull request calculates and extends the TPM PCR banks
     with bank specific file hashes completing the above change.

   - The "boot_aggregate", the first IMA measurement list record, is the
     "trusted boot" link between the pre-boot environment and the
     running OS. With TPM 2.0, the "boot_aggregate" record is not
     limited to being based on the SHA1 TPM PCR bank, but can be
     calculated based on any enabled bank, assuming the hash algorithm
     is also enabled in the kernel.

  Other changes include the following and five other bug fixes/code
  clean up:

   - supporting both a SHA1 and a larger "boot_aggregate" digest in a
     custom template format containing both the the SHA1 ('d') and
     larger digests ('d-ng') fields.

   - Initial hash table key fix, but additional changes would be good"

* tag 'integrity-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: Directly free *entry in ima_alloc_init_template() if digests is NULL
  ima: Call ima_calc_boot_aggregate() in ima_eventdigest_init()
  ima: Directly assign the ima_default_policy pointer to ima_rules
  ima: verify mprotect change is consistent with mmap policy
  evm: Fix possible memory leak in evm_calc_hmac_or_hash()
  ima: Set again build_ima_appraise variable
  ima: Remove redundant policy rule set in add_rules()
  ima: Fix ima digest hash table key calculation
  ima: Use ima_hash_algo for collision detection in the measurement list
  ima: Calculate and extend PCR with digests in ima_template_entry
  ima: Allocate and initialize tfm for each PCR bank
  ima: Switch to dynamically allocated buffer for template digests
  ima: Store template digest directly in ima_template_entry
  ima: Evaluate error in init_ima()
  ima: Switch to ima_hash_algo for boot aggregate

Allow user to use alternative implementations of compression tools,
such as pigz, pbzip2, pxz. For example, multi-threaded tools to
speed up the build:
$ make GZIP=pigz BZIP2=pbzip2

Variables _GZIP, _BZIP2, _LZOP are used internally because original env
vars are reserved by the tools. The use of GZIP in gzip tool is obsolete
since 2015. However, alternative implementations (e.g., pigz) still rely
on it. BZIP2, BZIP, LZOP vars are not obsolescent.

The credit goes to @grsecurity.

As a sidenote, for multi-threaded lzma, xz compression one can use:
$ export XZ_OPT="--threads=0"
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Many applications check for available kernel features via:

  - /proc/modules (loaded modules, present if CONFIG_MODULES=y)
  - $(MODLIB)/modules.builtin (builtin modules)

They fail to detect features if the kernel was built with CONFIG_MODULES=n
and modules.builtin isn't installed.

Therefore, add the target "_builtin_inst_" and make "install" and
"modules_install" depend on it.

Tests results:

  - make install: kernel image is copied as before, modules.builtin copied
  - make modules_install: (CONFIG_MODULES=n) nothing is copied, exit 1
Signed-off-by: Jonas Zeiger <jonas.zeiger@talpidae.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

When System.map was generated, the kernel used mksysmap to
filter the kernel symbols, but all the symbols with the
second letter 'L' in the kernel were filtered out, not just
the symbols starting with 'dot + L'.

For example:
ashimida@ubuntu:~/linux$ cat System.map |grep ' .L'
ashimida@ubuntu:~/linux$ nm -n vmlinux |grep ' .L'
ffff0000088028e0 t bLength_show
......
ffff0000092e0408 b PLLP_OUTC_lock
ffff0000092e0410 b PLLP_OUTA_lock

The original intent should be to filter out all local symbols
starting with '.L', so the dot should be escaped.

Fixes: 00902e98 ("mksysmap: Add h8300 local symbol pattern")
Signed-off-by: ashimida <ashimida@linux.alibaba.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Commit d503ac53 ("kbuild: rename LDFLAGS to KBUILD_LDFLAGS") missed
to update the documentation.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Align with the mmap / munmap APIs.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Now that is_vmlinux() is called only in new_module(), we can inline
the function call.

modname is the basename with '.o' is stripped. No need to compare it
with 'vmlinux.o'.

vmlinux is always located at the current working directory. No need
to strip the directory path.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

new_module() conditionally strips the .o because the modname has .o
suffix when it is called from read_symbols(), but no .o when it is
called from read_dump().

It is clearer to strip .o in read_symbols().

I also used flexible-array for mod->name.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Set have_vmlinux flag in a single place.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The meaning of 'skip' is obscure since it does not explain
"what to skip".

mod->skip is set when it is vmlinux or the module info came from
a dump file.

So, mod->skip is equivalent to (mod->is_vmlinux || mod->from_dump).

For the check in write_namespace_deps_files(), mod->is_vmlinux is
unneeded because the -d option is not passed in the first pass of
modpost.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

is_vmlinux() is called in several places to check whether the current
module is vmlinux or not.

It is faster and clearer to check mod->is_vmlinux flag.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

check_exports() is never called for vmlinux because mod->skip is set
for vmlinux.

Hence, check_for_gpl_usage() and check_for_unused() are not called
for vmlinux, either. is_vmlinux() is always false here.

Remove the is_vmlinux() calls, and hard-code the ".ko" suffix.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Previously, there were two cases where mod->is_dot_o is unset:

[1] the executable 'vmlinux' in the second pass of modpost
[2] modules loaded by read_dump()

I think [1] was intended usage to distinguish 'vmlinux.o' and 'vmlinux'.
Now that modpost does not parse the executable 'vmlinux', this case
does not happen.

[2] is obscure, maybe a bug. Module.symver stores module paths without
extension. So, none of modules loaded by read_dump() has the .o suffix,
and new_module() unsets ->is_dot_o. Anyway, it is not a big deal because
handle_symbol() is not called for the case.

To sum up, all the parsed ELF files are .o files.

mod->is_dot_o is unneeded.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Collect options for modules into a single place.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The -s option was added by commit 8d8d8289 ("kbuild: do not do
section mismatch checks on vmlinux in 2nd pass").

Now that the second pass does not parse vmlinux, this option is
unneeded.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

get_next_line() is no longer used. Remove.

grab_file() and release_file() are only used in modpost.c. Make them
static.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

grab_file() mmaps a file, but it is not so efficient here because
get_next_line() copies every line to the temporary buffer anyway.

read_text_file() and get_line() are simpler. get_line() exploits the
library function strchr().

Going forward, the missing *.symvers or *.cmd is a fatal error.
This should not happen because scripts/Makefile.modpost guards the
-i option files with $(wildcard $(input-symdump)).
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

One problem of grab_file() is that it cannot distinguish the following
two cases:

 - It cannot read the file (the file does not exist, or read permission
   is not set)

 - It can read the file, but the file size is zero

This is because grab_file() calls mmap(), which requires the mapped
length is greater than 0. Hence, grab_file() fails for both cases.

If an empty header file were included for checksum calculation, the
following warning would be printed:

  WARNING: modpost: could not open ...: Invalid argument

An empty file is a valid source file, so it should not fail.

Use read_text_file() instead. It can read a zero-length file.
Then, parse_file() will succeed with doing nothing.

Going forward, the first case (it cannot read the file) is a fatal
error. If the source file from which an object was compiled is missing,
something went wrong.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

I do not know how reliably this function works, but it looks dangerous
to me.

    strchr(sources, '\n');

... continues searching until it finds '\n' or it reaches the '\0'
terminator. In other words, 'sources' should be a null-terminated
string.

However, grab_file() just mmaps a file, so 'sources' is not terminated
with null byte. If the file does not contain '\n' at all, strchr() will
go beyond the mmap'ed memory.

Use read_text_file(), which loads the file content into a malloc'ed
buffer, appending null byte.

Here we are interested only in the first line of *.mod files. Use
get_line() helper to get the first line.

This also makes missing *.mod file a fatal error.

Commit 4be40e22 ("kbuild: do not emit src version warning for
non-modules") ignored missing *.mod files.

I do not fully understand what that commit addressed, but commit
91341d4b ("kbuild: introduce new option to enhance section mismatch
analysis") introduced partial section checks by using modpost. built-in.o
was parsed by modpost. Even modules had a problem because *.mod files
were created after the modpost check.

Commit b7dca6dd ("kbuild: create *.mod with full directory path and
remove MODVERDIR") stopped doing that. Now that modpost is only invoked
after the directory descend, *.mod files should always exist at the
modpost stage.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

modpost uses grab_file() to open a file, but it is not suitable for
a text file because the mmap'ed file is not terminated by null byte.
Actually, I see some issues for the use of grab_file().

The new helper, read_text_file() loads the whole file content into a
malloc'ed buffer, and appends a null byte. Then, get_line() reads
each line.

To handle text files, I intend to replace as follows:

  grab_file()    -> read_text_file()
  get_new_line() -> get_line()
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The three calls of get_modinfo() ("license", "import_ns", "version")
always return NULL for vmlinux(.o) because the built-in module info is
prefixed with __MODULE_INFO_PREFIX.

It is harmless to call get_modinfo(), but there is no point to search
for what apparently does not exist.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

As far as I understood, this code gets rid of '$Revision$' or '$Revision:'
of CVS, RCS or whatever in MODULE_VERSION() tags.

Remove the primeval code.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>