The following Qualcomm WCN399x Bluetooth controllers support the
Microsoft vendor extension and they are using 0xFD70 for VsMsftOpCode.
-WCN3990
-WCN3991
-WCN3998

< HCI Command: ogf 0x3f, ocf 0x0170, plen 1
  00
> HCI Event: 0x0e plen 18
  01 70 FD 00 00 1F 00 00 00 00 00 00 00 04 4D 53 46 54

The following test step was performed.
- Boot the device with WCN3991 and verify INFO print in dmesg.
Signed-off-by: Miao-chen Chou <mcchou@chromium.org>
Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Reviewed-by: Archie Pusaka <apusaka@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Just like MGMT_OP_START_DISCOVERY, we should reject
MGMT_OP_START_SERVICE_DISCOVERY with MGMT_STATUS_BUSY when we are paused
for suspend.
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

we should send hci reset command before bt turn off, which can reset bt
firmware status.
Signed-off-by: Tim Jiang <tjiang@codeaurora.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Add a missing SUSPEND_SCAN_ENABLE in passive scan, remove the separate
function for configuring le scan during suspend and update the request
complete function to clear both enable and disable tasks.

Fixes: dce0a4be ("Bluetooth: Set missing suspend task bits")
Reviewed-by: Alain Michaud <alainm@chromium.org>
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

In hci_uart_write_work, there is a loop/goto checking the value of
HCI_UART_TX_WAKEUP. If HCI_UART_TX_WAKEUP is set again, it keeps trying
hci_uart_dequeue; otherwise, it clears HCI_UART_SENDING and returns.

In hci_uart_tx_wakeup, if HCI_UART_SENDING is already set, it sets
HCI_UART_TX_WAKEUP, skips schedule_work and assumes the running/pending
hci_uart_write_work worker will do hci_uart_dequeue properly.

However, if the HCI_UART_SENDING check in hci_uart_tx_wakeup is done after
the loop breaks, but before HCI_UART_SENDING is cleared in
hci_uart_write_work, the schedule_work is skipped incorrectly.

Fix this race by changing the order of HCI_UART_SENDING and
HCI_UART_TX_WAKEUP modification.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Fixes: 82f5169b ("Bluetooth: hci_uart: add serdev driver support library")
Signed-off-by: Claire Chang <tientzu@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Add support to read FW build version from debugfs node.
This info can be read from
/sys/kernel/debug/bluetooth/hci0/firmware_info
Signed-off-by: Venkata Lakshmi Narayana Gubba <gubbaven@codeaurora.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

When alt mode 6 is not available, fallback to the kernel <= 5.7 behavior
of always using alt mode 1.

Prior to kernel 5.8, btusb would always use alt mode 1 for WBS (Wide
Band Speech aka mSBC aka transparent SCO).  In commit baac6276
("Bluetooth: btusb: handle mSBC audio over USB Endpoints") this
was changed to use alt mode 6, which is the recommended mode in the
Bluetooth spec (Specifications of the Bluetooth System, v5.0, Vol 4.B
§2.2.1).  However, many if not most BT USB adapters do not support alt
mode 6.  In fact, I have been unable to find any which do.

In kernel 5.8, this was changed to use alt mode 6, and if not available,
use alt mode 0.  But mode 0 has a zero byte max packet length and can
not possibly work.  It is just there as a zero-bandwidth dummy mode to
work around a USB flaw that would prevent device enumeration if
insufficient bandwidth were available for the lowest isoc mode
supported.

In effect, WBS was broken for all USB-BT adapters that do not support
alt 6, which appears to nearly all of them.

Then in commit 461f95f0 ("Bluetooth: btusb: USB alternate setting 1 for
WBS") the 5.7 behavior was restored, but only for Realtek adapters.

I've tested a Broadcom BRCM20702A and CSR 8510 adapter, both work with
the 5.7 behavior and do not with the 5.8.

So get rid of the Realtek specific flag and use the 5.7 behavior for all
adapters as a fallback when alt 6 is not available.  This was the
kernel's behavior prior to 5.8 and I can find no adapters for which it
is not correct.  And even if there is an adapter for which this does not
work, the current behavior would be to fall back to alt 0, which can not
possibly work either, and so is no better.
Signed-off-by: Trent Piepho <tpiepho@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Some resource should be released in the error handling path of the probe
function, as already done in the remove function.

The remove function was fixed in commit 5052de8d ("soc: qcom: smd:
Transition client drivers from smd to rpmsg")

Fixes: 1511cc75 ("Bluetooth: Introduce Qualcomm WCNSS SMD based HCI driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Pull staging / IIO driver updates from Greg KH:
 "Here is the big staging and IIO driver pull request for 5.11-rc1

  Lots of different things in here:

   - loads of driver updates

   - so many coding style cleanups

   - new IIO drivers

   - Android ION code is finally removed from the tree

   - wimax drivers are moved to staging on their way out of the kernel

  Nothing really exciting, just the constant grind of kernel development :)

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

* tag 'staging-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (341 commits)
  staging: olpc_dcon: Do not call platform_device_unregister() in dcon_probe()
  staging: most: Fix spelling mistake "tranceiver" -> "transceiver"
  staging: qlge: remove duplicate word in comment
  staging: comedi: mf6x4: Fix AI end-of-conversion detection
  staging: greybus: Add TODO item about modernizing the pwm code
  pinctrl: ralink: add a pinctrl driver for the rt2880 family
  dt-bindings: pinctrl: rt2880: add binding document
  staging: rtl8723bs: remove ELEMENT_ID enum
  staging: rtl8723bs: remove unused macros
  staging: rtl8723bs: replace EID_EXTCapability
  staging: rtl8723bs: replace EID_BSSIntolerantChlReport
  staging: rtl8723bs: replace EID_BSSCoexistence
  staging: rtl8723bs: replace _MME_IE_
  staging: rtl8723bs: replace _WAPI_IE_
  staging: rtl8723bs: replace _EXT_SUPPORTEDRATES_IE_
  staging: rtl8723bs: replace _ERPINFO_IE_
  staging: rtl8723bs: replace _CHLGETXT_IE_
  staging: rtl8723bs: replace _COUNTRY_IE_
  staging: rtl8723bs: replace _IBSS_PARA_IE_
  staging: rtl8723bs: replace _TIM_IE_
  ...

Pull char / misc driver updates from Greg KH:
 "Here is the big char/misc driver update for 5.11-rc1.

  Continuing the tradition of previous -rc1 pulls, there seems to be
  more and more tiny driver subsystems flowing through this tree.

  Lots of different things, all of which have been in linux-next for a
  while with no reported issues:

   - extcon driver updates

   - habannalab driver updates

   - mei driver updates

   - uio driver updates

   - binder fixes and features added

   - soundwire driver updates

   - mhi bus driver updates

   - phy driver updates

   - coresight driver updates

   - fpga driver updates

   - speakup driver updates

   - slimbus driver updates

   - various small char and misc driver updates"

* tag 'char-misc-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (305 commits)
  extcon: max77693: Fix modalias string
  extcon: fsa9480: Support TI TSU6111 variant
  extcon: fsa9480: Rewrite bindings in YAML and extend
  dt-bindings: extcon: add binding for TUSB320
  extcon: Add driver for TI TUSB320
  slimbus: qcom: fix potential NULL dereference in qcom_slim_prg_slew()
  siox: Make remove callback return void
  siox: Use bus_type functions for probe, remove and shutdown
  spmi: Add driver shutdown support
  spmi: fix some coding style issues at the spmi core
  spmi: get rid of a warning when built with W=1
  uio: uio_hv_generic: use devm_kzalloc() for private data alloc
  uio: uio_fsl_elbc_gpcm: use device-managed allocators
  uio: uio_aec: use devm_kzalloc() for uio_info object
  uio: uio_cif: use devm_kzalloc() for uio_info object
  uio: uio_netx: use devm_kzalloc() for or uio_info object
  uio: uio_mf624: use devm_kzalloc() for uio_info object
  uio: uio_sercos3: use device-managed functions for simple allocs
  uio: uio_dmem_genirq: finalize conversion of probe to devm_ handlers
  uio: uio_dmem_genirq: convert simple allocations to device-managed
  ...

Merge tag 'driver-core-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the big driver core updates for 5.11-rc1

  This time there was a lot of different work happening here for some
  reason:

   - redo of the fwnode link logic, speeding it up greatly

   - auxiliary bus added (this was a tag that will be pulled in from
     other trees/maintainers this merge window as well, as driver
     subsystems started to rely on it)

   - platform driver core cleanups on the way to fixing some long-time
     api updates in future releases

   - minor fixes and tweaks.

  All have been in linux-next with no (finally) reported issues. Testing
  there did helped in shaking issues out a lot :)"

* tag 'driver-core-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (39 commits)
  driver core: platform: don't oops in platform_shutdown() on unbound devices
  ACPI: Use fwnode_init() to set up fwnode
  misc: pvpanic: Replace OF headers by mod_devicetable.h
  misc: pvpanic: Combine ACPI and platform drivers
  usb: host: sl811: Switch to use platform_get_mem_or_io()
  vfio: platform: Switch to use platform_get_mem_or_io()
  driver core: platform: Introduce platform_get_mem_or_io()
  dyndbg: fix use before null check
  soc: fix comment for freeing soc_dev_attr
  driver core: platform: use bus_type functions
  driver core: platform: change logic implementing platform_driver_probe
  driver core: platform: reorder functions
  driver core: make driver_probe_device() static
  driver core: Fix a couple of typos
  driver core: Reorder devices on successful probe
  driver core: Delete pointless parameter in fwnode_operations.add_links
  driver core: Refactor fw_devlink feature
  efi: Update implementation of add_links() to create fwnode links
  of: property: Update implementation of add_links() to create fwnode links
  driver core: Use device's fwnode to check if it is waiting for suppliers
  ...

Pull tty / serial updates from Greg KH:
 "Here is the "large" set of tty and serial patches for 5.11-rc1.

  Nothing major at all, some cleanups and some driver removals, always a
  nice sign:

   - build warning cleanups

   - vt locking and logic unwinding and cleanups

   - tiny serial driver fixes and updates

   - removal of the synclink serial driver as it's no longer needed

   - removal of dead termiox code

  All of this has been in linux-next for a while with no reported issues"

* tag 'tty-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (89 commits)
  serial: 8250_pci: Drop bogus __refdata annotation
  tty: serial: meson: enable console as module
  serial: 8250_omap: Avoid FIFO corruption caused by MDR1 access
  serial: imx: Move imx_uart_probe_dt() content into probe()
  serial: imx: Remove unneeded of_device_get_match_data() NULL check
  tty: Fix whitespace inconsistencies in vt_io_ioctl
  serial_core: Check for port state when tty is in error state
  dt-bindings: serial: Update DT binding docs to support SiFive FU740 SoC
  tty: use const parameters in port-flag accessors
  tty: use assign_bit() in port-flag accessors
  earlycon: drop semicolon from earlycon macro
  tty: Remove dead termiox code
  tty/serial/imx: Enable TXEN bit in imx_poll_init().
  tty : serial: jsm: Fixed file by adding spacing
  tty: serial: uartlite: Support probe deferral
  earlycon: simplify earlycon-table implementation
  tty: serial: bcm63xx: lower driver dependencies
  serial: mxs-auart: Remove unneeded platform_device_id
  serial: 8250-mtk: Fix reference leak in mtk8250_probe
  serial: imx: Remove unused .id_table support
  ...

Pull USB / Thunderbolt updates from Greg KH:
 "Here is the big USB and thunderbolt pull request for 5.11-rc1.

  Nothing major in here, just the grind of constant development to
  support new hardware and fix old issues:

   - thunderbolt updates for new USB4 hardware

   - cdns3 major driver updates

   - lots of typec updates and additions as more hardware is available

   - usb serial driver updates and fixes

   - other tiny USB driver updates

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

* tag 'usb-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (172 commits)
  usb: phy: convert comma to semicolon
  usb: ucsi: convert comma to semicolon
  usb: typec: tcpm: convert comma to semicolon
  usb: typec: tcpm: Update vbus_vsafe0v on init
  usb: typec: tcpci: Enable bleed discharge when auto discharge is enabled
  usb: typec: Add class for plug alt mode device
  USB: typec: tcpci: Add Bleed discharge to POWER_CONTROL definition
  USB: typec: tcpm: Add a 30ms room for tPSSourceOn in PR_SWAP
  USB: typec: tcpm: Fix PR_SWAP error handling
  USB: typec: tcpm: Hard Reset after not receiving a Request
  USB: gadget: f_fs: remove likely/unlikely
  usb: gadget: f_fs: Re-use SS descriptors for SuperSpeedPlus
  USB: gadget: f_midi: setup SuperSpeed Plus descriptors
  USB: gadget: f_acm: add support for SuperSpeed Plus
  USB: gadget: f_rndis: fix bitrate for SuperSpeed and above
  usb: typec: intel_pmc_mux: Configure cable generation value for USB4
  MAINTAINERS: Add myself as a reviewer for CADENCE USB3 DRD IP DRIVER
  usb: chipidea: ci_hdrc_imx: Use of_device_get_match_data()
  usb: chipidea: usbmisc_imx: Use of_device_get_match_data()
  usb: cdns3: fix NULL pointer dereference on no platform data
  ...

Pull sound updates from Takashi Iwai:
 "Lots of changes (slightly more code increase than usual) at this time,
  while most of code changes are ASoC driver-specific.

  Here are some highlights:

  Core:

   - The new auxiliary bus implementation for Intel DSP, which will be
     used by other drivers as well

   - Lots of ASoC core cleanups and refactoring

   - UBSAN and KCSAN fixes in rawmidi, sequencer and a few others

   - Compress-offload API enhancement for the pause during draining

  HD- and USB-audio:

   - Enhancements of the USB-audio implicit feedback support, including
     better full-duplex operations

   - Continued CA0132 improvements and fixes

   - A few new quirk entries, HDMI audio fixes

  ASoC:

   - Support for boot time selection of Intel DSP firmware, which should
     help distros/users testing new stuff more easily; the kconfig was
     moved to boot time option, too

   - Some basic DPCM support in audio graph card

   - Removal of old pre-DT Freescale drivers

   - Support for Allwinner H6 I2S, Analog Devices ADAU1372, Intel
     Alderlake-S, GMediatek MT8192, NXP i.MX HDMI and XCVR, Realtek
     RT715, Qualcomm SM8250 and simple GPIO based muxes"

* tag 'sound-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (445 commits)
  ALSA: pcm: oss: Fix potential out-of-bounds shift
  ALSA: usb-audio: Fix potential out-of-bounds shift
  ALSA: hda/ca0132 - Add ZxR surround DAC setup.
  ALSA: hda/ca0132 - Add 8051 PLL write helper functions.
  ALSA: hda/hdmi: packet buffer index must be set before reading value
  ASoC: SOF: imx: update kernel-doc description
  ASoC: mediatek: mt8183: delete some unreachable code
  ASoC: mediatek: mt8183: add PM ops to machine drivers
  ASoC: topology: Fix wrong size check
  ASoC: topology: Add missing size check
  ASoC: SOF: Intel: hda: fix the condition passed to sof_dev_dbg_or_err
  ASoC: SOF: modify the SOF_DBG flags
  ASoC: SOF: Intel: hda: remove duplicated status dump
  ASoC: rt1015p: delay 300ms after SDB pulling high for calibration
  ASoC: rt1015p: move SDB control from trigger to DAPM
  ASoC: wm_adsp: remove "ctl" from list on error in wm_adsp_create_control()
  ALSA: usb-audio: Fix control 'access overflow' errors from chmap
  ALSA: hda/hdmi: always print pin NIDs as hexadecimal
  ALSA: hda/realtek - Add supported for more Lenovo ALC285 Headset Button
  ALSA: hda/ca0132 - Remove now unnecessary DSP setup functions.
  ...

Pull networking updates from Jakub Kicinski:
 "Core:

   - support "prefer busy polling" NAPI operation mode, where we defer
     softirq for some time expecting applications to periodically busy
     poll

   - AF_XDP: improve efficiency by more batching and hindering the
     adjacency cache prefetcher

   - af_packet: make packet_fanout.arr size configurable up to 64K

   - tcp: optimize TCP zero copy receive in presence of partial or
     unaligned reads making zero copy a performance win for much smaller
     messages

   - XDP: add bulk APIs for returning / freeing frames

   - sched: support fragmenting IP packets as they come out of conntrack

   - net: allow virtual netdevs to forward UDP L4 and fraglist GSO skbs

  BPF:

   - BPF switch from crude rlimit-based to memcg-based memory accounting

   - BPF type format information for kernel modules and related tracing
     enhancements

   - BPF implement task local storage for BPF LSM

   - allow the FENTRY/FEXIT/RAW_TP tracing programs to use
     bpf_sk_storage

  Protocols:

   - mptcp: improve multiple xmit streams support, memory accounting and
     many smaller improvements

   - TLS: support CHACHA20-POLY1305 cipher

   - seg6: add support for SRv6 End.DT4/DT6 behavior

   - sctp: Implement RFC 6951: UDP Encapsulation of SCTP

   - ppp_generic: add ability to bridge channels directly

   - bridge: Connectivity Fault Management (CFM) support as is defined
     in IEEE 802.1Q section 12.14.

  Drivers:

   - mlx5: make use of the new auxiliary bus to organize the driver
     internals

   - mlx5: more accurate port TX timestamping support

   - mlxsw:
      - improve the efficiency of offloaded next hop updates by using
        the new nexthop object API
      - support blackhole nexthops
      - support IEEE 802.1ad (Q-in-Q) bridging

   - rtw88: major bluetooth co-existance improvements

   - iwlwifi: support new 6 GHz frequency band

   - ath11k: Fast Initial Link Setup (FILS)

   - mt7915: dual band concurrent (DBDC) support

   - net: ipa: add basic support for IPA v4.5

  Refactor:

   - a few pieces of in_interrupt() cleanup work from Sebastian Andrzej
     Siewior

   - phy: add support for shared interrupts; get rid of multiple driver
     APIs and have the drivers write a full IRQ handler, slight growth
     of driver code should be compensated by the simpler API which also
     allows shared IRQs

   - add common code for handling netdev per-cpu counters

   - move TX packet re-allocation from Ethernet switch tag drivers to a
     central place

   - improve efficiency and rename nla_strlcpy

   - number of W=1 warning cleanups as we now catch those in a patchwork
     build bot

  Old code removal:

   - wan: delete the DLCI / SDLA drivers

   - wimax: move to staging

   - wifi: remove old WDS wifi bridging support"

* tag 'net-next-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1922 commits)
  net: hns3: fix expression that is currently always true
  net: fix proc_fs init handling in af_packet and tls
  nfc: pn533: convert comma to semicolon
  af_vsock: Assign the vsock transport considering the vsock address flags
  af_vsock: Set VMADDR_FLAG_TO_HOST flag on the receive path
  vsock_addr: Check for supported flag values
  vm_sockets: Add VMADDR_FLAG_TO_HOST vsock flag
  vm_sockets: Add flags field in the vsock address data structure
  net: Disable NETIF_F_HW_TLS_TX when HW_CSUM is disabled
  tcp: Add logic to check for SYN w/ data in tcp_simple_retransmit
  net: mscc: ocelot: install MAC addresses in .ndo_set_rx_mode from process context
  nfc: s3fwrn5: Release the nfc firmware
  net: vxget: clean up sparse warnings
  mlxsw: spectrum_router: Use eXtended mezzanine to offload IPv4 router
  mlxsw: spectrum: Set KVH XLT cache mode for Spectrum2/3
  mlxsw: spectrum_router_xm: Introduce basic XM cache flushing
  mlxsw: reg: Add Router LPM Cache Enable Register
  mlxsw: reg: Add Router LPM Cache ML Delete Register
  mlxsw: spectrum_router_xm: Implement L-value tracking for M-index
  mlxsw: reg: Add XM Router M Table Register
  ...

Merge misc updates from Andrew Morton:

 - a few random little subsystems

 - almost all of the MM patches which are staged ahead of linux-next
   material. I'll trickle to post-linux-next work in as the dependents
   get merged up.

Subsystems affected by this patch series: kthread, kbuild, ide, ntfs,
ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache,
gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation,
kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc,
uaccess, zram, and cleanups).

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (200 commits)
  mm: cleanup kstrto*() usage
  mm: fix fall-through warnings for Clang
  mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at
  mm: shmem: convert shmem_enabled_show to use sysfs_emit_at
  mm:backing-dev: use sysfs_emit in macro defining functions
  mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening
  mm: use sysfs_emit for struct kobject * uses
  mm: fix kernel-doc markups
  zram: break the strict dependency from lzo
  zram: add stat to gather incompressible pages since zram set up
  zram: support page writeback
  mm/process_vm_access: remove redundant initialization of iov_r
  mm/zsmalloc.c: rework the list_add code in insert_zspage()
  mm/zswap: move to use crypto_acomp API for hardware acceleration
  mm/zswap: fix passing zero to 'PTR_ERR' warning
  mm/zswap: make struct kernel_param_ops definitions const
  userfaultfd/selftests: hint the test runner on required privilege
  userfaultfd/selftests: fix retval check for userfaultfd_open()
  userfaultfd/selftests: always dump something in modes
  userfaultfd: selftests: make __{s,u}64 format specifiers portable
  ...

Range checks can folded into proper conversion function.  kstrto*() exist
for all arithmetic types.

Link: https://lkml.kernel.org/r/20201122123759.GC92364@localhost.localdomainSigned-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In preparation to enable -Wimplicit-fallthrough for Clang, fix a couple of
warnings by explicitly adding a break statement instead of just letting
the code fall through to the next, and by adding a fallthrough
pseudo-keyword in places where the code is intended to fall through.

Link: https://github.com/KSPP/linux/issues/115
Link: https://lkml.kernel.org/r/f5756988b8842a3f10008fbc5b0a654f828920a9.1605896059.git.gustavoars@kernel.orgSigned-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Convert the unbounded uses of sprintf to sysfs_emit.

A few conversions may now not end in a newline if the output buffer is
overflowed.

Link: https://lkml.kernel.org/r/0c90a90f466167f8c37de4b737553cf49c4a277f.1605376435.git.joe@perches.comSigned-off-by: Joe Perches <joe@perches.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Update the function to use sysfs_emit_at while neatening the uses of
sprintf and overwriting the last space char with a newline to avoid
possible output buffer overflow.

Miscellanea:

 - in shmem_enabled_show, the removal of the indirected use of fmt
   allows __printf verification

Link: https://lkml.kernel.org/r/b612a93825e5ea330cb68d2e8b516e9687a06cc6.1605376435.git.joe@perches.comSigned-off-by: Joe Perches <joe@perches.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The cocci script used in commit bdacbb8d04f ("mm: Use sysfs_emit for
struct kobject * uses") does not convert the name##_show macro because the
macro uses concatenation via ##.

Convert it by hand.

Link: https://lkml.kernel.org/r/45ec6cfc177d743f9c0ebaf35e43969dce43af42.1605376435.git.joe@perches.comSigned-off-by: Joe Perches <joe@perches.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Convert the only use of sprintf with struct kobject * that the cocci
script could not convert.

Miscellanea:

 - Neaten the uses of a constant string with sysfs_emit to use a const
   char * to reduce overall object size

Link: https://lkml.kernel.org/r/7df6be66bbd68e1a0bca9d35aca1341dbf94d2a7.1605376435.git.joe@perches.comSigned-off-by: Joe Perches <joe@perches.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "mm: Convert sysfs sprintf family to sysfs_emit", v2.

Use the new sysfs_emit family and not the sprintf family.

This patch (of 5):

Use the sysfs_emit function instead of the sprintf family.

Done with cocci script as in commit 3c6bff3c ("RDMA: Convert sysfs
kobject * show functions to use sysfs_emit()")

Link: https://lkml.kernel.org/r/cover.1605376435.git.joe@perches.com
Link: https://lkml.kernel.org/r/9c249215bad6df616ba0410ad980042694970c1b.1605376435.git.joe@perches.comSigned-off-by: Joe Perches <joe@perches.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Kernel-doc markups should use this format:
        identifier - description

Fix some issues on mm files:

1) The definition for get_user_pages_locked() doesn't follow it.  Also,
   it expects a short descrpition at the header, followed by a long one,
   after the parameters.  Fix it.

2) Kernel-doc requires that a kernel-doc markup to be immediately below
   the function prototype, as otherwise it will rename it.  So, move
   get_pfnblock_flags_mask() description to the right place.

3) Make invalidate_mapping_pagevec() to also follow the expected
   kernel-doc format.

While here, fix a few minor English syntax issues, as suggested
by Matthew:
	will used -> will be used
	similar with -> similar to

Link: https://lkml.kernel.org/r/80e85dddc92d333bc2159ee8a2294921612e8745.1605521731.git.mchehab+huawei@kernel.orgSigned-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Suggested-by: Mattew Wilcox <willy@infradead.org>	[English fixes]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

From the beginning, the zram block device always enabled CRYPTO_LZO,
since lzo-rle is hardcoded as the fallback compression algorithm.  As a
consequence, on systems where another compression algorithm is chosen
(e.g.  CRYPTO_ZSTD), the lzo kernel module becomes unused, while still
having to be built/loaded.

This patch removes the hardcoded lzo-rle dependency and allows the user
to select the default compression algorithm for zram at build time.  The
previous behaviour is kept, as the default algorithm is still lzo-rle.

Link: https://lkml.kernel.org/r/20201207121245.50529-1-rsalvaterra@gmail.comSigned-off-by: Rui Salvaterra <rsalvaterra@gmail.com>
Suggested-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Suggested-by: Minchan Kim <minchan@kernel.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently, zram supports the stat via /sys/block/zram/mm_stat to represent
how many of incompressible pages are stored at the moment but it couldn't
show how many times incompressible pages were wrote down since zram set
up.  It's also good indication to see how zram is effective in the system.

Link: https://lkml.kernel.org/r/20201130201907.1284910-1-minchan@kernel.orgSigned-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There is demand to writeback specific process pages to backing store
instead of all idles pages in the system due to storage wear out concerns
and to launching latency of apps which are most of the time idle but are
critical for resume latency.

This patch extends the writeback knob to support a specific page
writeback.

Link: https://lkml.kernel.org/r/20201020190506.3758660-1-minchan@kernel.orgSigned-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The pointer iov_r is being initialized with a value that is never read and
it is being updated later with a new value.  The initialization is
redundant and can be removed.

Link: https://lkml.kernel.org/r/20201102120614.694917-1-colin.king@canonical.comSigned-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Rework the list_add code to make it more readable and simple.

Link: https://lkml.kernel.org/r/20201015130107.65195-1-linmiaohe@huawei.comSigned-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Right now, all new ZIP drivers are adapted to crypto_acomp APIs rather
than legacy crypto_comp APIs.  Tradiontal ZIP drivers like lz4,lzo etc
have been also wrapped into acomp via scomp backend.  But zswap.c is still
using the old APIs.  That means zswap won't be able to work on any new ZIP
drivers in kernel.

This patch moves to use cryto_acomp APIs to fix the disconnected bridge
between new ZIP drivers and zswap.  It is probably the first real user to
use acomp but perhaps not a good example to demonstrate how multiple acomp
requests can be executed in parallel in one acomp instance.  frontswap is
doing page load and store page by page synchronously.  swap_writepage()
depends on the completion of frontswap_store() to decide if it should call
__swap_writepage() to swap to disk.

However this patch creates multiple acomp instances, so multiple threads
running on multiple different cpus can actually do (de)compression
parallelly, leveraging the power of multiple ZIP hardware queues.  This is
also consistent with frontswap's page management model.

The old zswap code uses atomic context and avoids the race conditions
while shared resources like zswap_dstmem are accessed.  Here since acomp
can sleep, per-cpu mutex is used to replace preemption-disable.

While it is possible to make mm/page_io.c and mm/frontswap.c support async
(de)compression in some way, the entire design requires careful thinking
and performance evaluation.  For the first step, the base with fixed
connection between ZIP drivers and zswap should be built.

Link: https://lkml.kernel.org/r/20201107065332.26992-1-song.bao.hua@hisilicon.comSigned-off-by: Barry Song <song.bao.hua@hisilicon.com>
Acked-by: Vitaly Wool <vitalywool@gmail.com>
Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David S. Miller <davem@davemloft.net>
Cc: Mahipal Challa <mahipalreddy2006@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Zhou Wang <wangzhou1@hisilicon.com>
Cc: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix smatch warning:

  mm/zswap.c:425 zswap_cpu_comp_prepare() warn: passing zero to 'PTR_ERR'

crypto_alloc_comp() never return NULL, use IS_ERR instead of
IS_ERR_OR_NULL to fix this.

Link: https://lkml.kernel.org/r/20201031055615.28080-1-yuehaibing@huawei.com
Fixes: f1c54846 ("zswap: dynamic pool creation")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

These should be const, so make it so.

Link: https://lkml.kernel.org/r/1791535ee0b00f4a5c68cc4a8adada06593ad8f1.1601770305.git.joe@perches.comSigned-off-by: Joe Perches <joe@perches.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: "Maciej S. Szmigiero" <mail@maciej.szmigiero.name>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Now userfaultfd test program requires either root or ptrace privilege due
to the signal/event tests.  When UFFDIO_API failed, hint the test runner
about this fact verbosely.

Link: https://lkml.kernel.org/r/20201208024709.7701-4-peterx@redhat.comSigned-off-by: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

userfaultfd_open() returns 1 for errors rather than negatives.  Fix it on
all the callers so when UFFDIO_API failed the test will bail out.

Link: https://lkml.kernel.org/r/20201208024709.7701-3-peterx@redhat.comSigned-off-by: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "userfaultfd: selftests: Small fixes".

Some very trivial fixes that I kept locally to userfaultfd selftest
program.

This patch (of 3):

BOUNCE_POLL is a special bit that if cleared it means "READ" instead.
Dump that too otherwise we'll see tests with empty modes.

Link: https://lkml.kernel.org/r/20201208024709.7701-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20201208024709.7701-2-peterx@redhat.comSigned-off-by: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

On certain platforms (powerpcle is the one on which I ran into this),
"%Ld" and "%Lu" are unsuitable for printing __s64 and __u64, respectively,
resulting in build warnings.  Cast to {u,}int64_t, and use the PRI{d,u}64
macros defined in inttypes.h to print them.  This ought to be portable to
all platforms.

Splitting this off into a separate macro lets us remove some lines, and
get rid of some (I would argue) stylistically odd cases where we joined
printf() and exit() into a single statement with a ,.

Finally, this also fixes a "missing braces around initializer" warning
when we initialize prms in wp_range().

[axelrasmussen@google.com: v2]
  Link: https://lkml.kernel.org/r/20201203180244.1811601-1-axelrasmussen@google.com

Link: https://lkml.kernel.org/r/20201202211542.1121189-1-axelrasmussen@google.comSigned-off-by: Axel Rasmussen <axelrasmussen@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Joe Perches <joe@perches.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Alan Gilbert <dgilbert@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

With this change, when the knob is set to 0, it allows unprivileged users
to call userfaultfd, like when it is set to 1, but with the restriction
that page faults from only user-mode can be handled.  In this mode, an
unprivileged user (without SYS_CAP_PTRACE capability) must pass
UFFD_USER_MODE_ONLY to userfaultd or the API will fail with EPERM.

This enables administrators to reduce the likelihood that an attacker with
access to userfaultfd can delay faulting kernel code to widen timing
windows for other exploits.

The default value of this knob is changed to 0.  This is required for
correct functioning of pipe mutex.  However, this will fail postcopy live
migration, which will be unnoticeable to the VM guests.  To avoid this,
set 'vm.userfault = 1' in /sys/sysctl.conf.

The main reason this change is desirable as in the short term is that the
Android userland will behave as with the sysctl set to zero.  So without
this commit, any Linux binary using userfaultfd to manage its memory would
behave differently if run within the Android userland.  For more details,
refer to Andrea's reply [1].

[1] https://lore.kernel.org/lkml/20200904033438.GI9411@redhat.com/

Link: https://lkml.kernel.org/r/20201120030411.2690816-3-lokeshgidra@google.comSigned-off-by: Lokesh Gidra <lokeshgidra@google.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Daniel Colascione <dancol@dancol.org>
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: <calin@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Nitin Gupta <nigupta@nvidia.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Daniel Colascione <dancol@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "Control over userfaultfd kernel-fault handling", v6.

This patch series is split from [1].  The other series enables SELinux
support for userfaultfd file descriptors so that its creation and movement
can be controlled.

It has been demonstrated on various occasions that suspending kernel code
execution for an arbitrary amount of time at any access to userspace
memory (copy_from_user()/copy_to_user()/...) can be exploited to change
the intended behavior of the kernel.  For instance, handling page faults
in kernel-mode using userfaultfd has been exploited in [2, 3].  Likewise,
FUSE, which is similar to userfaultfd in this respect, has been exploited
in [4, 5] for similar outcome.

This small patch series adds a new flag to userfaultfd(2) that allows
callers to give up the ability to handle kernel-mode faults with the
resulting UFFD file object.  It then adds a 'user-mode only' option to the
unprivileged_userfaultfd sysctl knob to require unprivileged callers to
use this new flag.

The purpose of this new interface is to decrease the chance of an
unprivileged userfaultfd user taking advantage of userfaultfd to enhance
security vulnerabilities by lengthening the race window in kernel code.

[1] https://lore.kernel.org/lkml/20200211225547.235083-1-dancol@google.com/
[2] https://duasynt.com/blog/linux-kernel-heap-spray
[3] https://duasynt.com/blog/cve-2016-6187-heap-off-by-one-exploit
[4] https://googleprojectzero.blogspot.com/2016/06/exploiting-recursion-in-linux-kernel_20.html
[5] https://bugs.chromium.org/p/project-zero/issues/detail?id=808

This patch (of 2):

userfaultfd handles page faults from both user and kernel code.  Add a new
UFFD_USER_MODE_ONLY flag for userfaultfd(2) that makes the resulting
userfaultfd object refuse to handle faults from kernel mode, treating
these faults as if SIGBUS were always raised, causing the kernel code to
fail with EFAULT.

A future patch adds a knob allowing administrators to give some processes
the ability to create userfaultfd file objects only if they pass
UFFD_USER_MODE_ONLY, reducing the likelihood that these processes will
exploit userfaultfd's ability to delay kernel page faults to open timing
windows for future exploits.

Link: https://lkml.kernel.org/r/20201120030411.2690816-1-lokeshgidra@google.com
Link: https://lkml.kernel.org/r/20201120030411.2690816-2-lokeshgidra@google.comSigned-off-by: Daniel Colascione <dancol@google.com>
Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <calin@google.com>
Cc: Daniel Colascione <dancol@dancol.org>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nitin Gupta <nigupta@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Shaohua Li <shli@fb.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

CONFIG_PAGE_POISONING_ZERO uses the zero pattern instead of 0xAA.  It was
introduced by commit 1414c7f4 ("mm/page_poisoning.c: allow for zero
poisoning"), noting that using zeroes retains the benefit of sanitizing
content of freed pages, with the benefit of not having to zero them again
on alloc, and the downside of making some forms of corruption (stray
writes of NULLs) harder to detect than with the 0xAA pattern.  Together
with CONFIG_PAGE_POISONING_NO_SANITY it made possible to sanitize the
contents on free without checking it back on alloc.

These days we have the init_on_free() option to achieve sanitization with
zeroes and to save clearing on alloc (and without checking on alloc).
Arguably if someone does choose to check the poison for corruption on
alloc, the savings of not clearing the page are secondary, and it makes
sense to always use the 0xAA poison pattern.  Thus, remove the
CONFIG_PAGE_POISONING_ZERO option for being redundant.

Link: https://lkml.kernel.org/r/20201113104033.22907-6-vbabka@suse.czSigned-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Laura Abbott <labbott@kernel.org>
Cc: Mateusz Nosek <mateusznosek0@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

CONFIG_PAGE_POISONING_NO_SANITY skips the check on page alloc whether the
poison pattern was corrupted, suggesting a use-after-free.  The motivation
to introduce it in commit 8823b1db ("mm/page_poison.c: enable
PAGE_POISONING as a separate option") was to simply sanitize freed pages,
optimally together with CONFIG_PAGE_POISONING_ZERO.

These days we have an init_on_free=1 boot option, which makes this use
case of page poisoning redundant.  For sanitizing, writing zeroes is
sufficient, there is pretty much no benefit from writing the 0xAA poison
pattern to freed pages, without checking it back on alloc.  Thus, remove
this option and suggest init_on_free instead in the main config's help.

Link: https://lkml.kernel.org/r/20201113104033.22907-5-vbabka@suse.czSigned-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Laura Abbott <labbott@kernel.org>
Cc: Mateusz Nosek <mateusznosek0@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>