Explicitly exempt ZONE_DEVICE pages from kvm_is_reserved_pfn() and
instead manually handle ZONE_DEVICE on a case-by-case basis.  For things
like page refcounts, KVM needs to treat ZONE_DEVICE pages like normal
pages, e.g. put pages grabbed via gup().  But for flows such as setting
A/D bits or shifting refcounts for transparent huge pages, KVM needs to
to avoid processing ZONE_DEVICE pages as the flows in question lack the
underlying machinery for proper handling of ZONE_DEVICE pages.

This fixes a hang reported by Adam Borowski[*] in dev_pagemap_cleanup()
when running a KVM guest backed with /dev/dax memory, as KVM straight up
doesn't put any references to ZONE_DEVICE pages acquired by gup().

Note, Dan Williams proposed an alternative solution of doing put_page()
on ZONE_DEVICE pages immediately after gup() in order to simplify the
auditing needed to ensure is_zone_device_page() is called if and only if
the backing device is pinned (via gup()).  But that approach would break
kvm_vcpu_{un}map() as KVM requires the page to be pinned from map() 'til
unmap() when accessing guest memory, unlike KVM's secondary MMU, which
coordinates with mmu_notifier invalidations to avoid creating stale
page references, i.e. doesn't rely on pages being pinned.

[*] http://lkml.kernel.org/r/20190919115547.GA17963@angband.plReported-by: Adam Borowski <kilobyte@angband.pl>
Analyzed-by: David Hildenbrand <david@redhat.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: stable@vger.kernel.org
Fixes: 3565fce3 ("mm, x86: get_user_pages() for dax mappings")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Streamline the PID.PIR check and change its call sites to use
the newly added helper.
Suggested-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

When vCPU enters block phase, pi_pre_block() inserts vCPU to a per pCPU
linked list of all vCPUs that are blocked on this pCPU. Afterwards, it
changes PID.NV to POSTED_INTR_WAKEUP_VECTOR which its handler
(wakeup_handler()) is responsible to kick (unblock) any vCPU on that
linked list that now has pending posted interrupts.

While vCPU is blocked (in kvm_vcpu_block()), it may be preempted which
will cause vmx_vcpu_pi_put() to set PID.SN.  If later the vCPU will be
scheduled to run on a different pCPU, vmx_vcpu_pi_load() will clear
PID.SN but will also *overwrite PID.NDST to this different pCPU*.
Instead of keeping it with original pCPU which vCPU had entered block
phase on.

This results in an issue because when a posted interrupt is delivered, as
the wakeup_handler() will be executed and fail to find blocked vCPU on
its per pCPU linked list of all vCPUs that are blocked on this pCPU.
Which is due to the vCPU being placed on a *different* per pCPU
linked list i.e. the original pCPU in which it entered block phase.

The regression is introduced by commit c112b5f5 ("KVM: x86:
Recompute PID.ON when clearing PID.SN"). Therefore, partially revert
it and reintroduce the condition in vmx_vcpu_pi_load() responsible for
avoiding changing PID.NDST when loading a blocked vCPU.

Fixes: c112b5f5 ("KVM: x86: Recompute PID.ON when clearing PID.SN")
Tested-by: Nathan Ni <nathan.ni@oracle.com>
Co-developed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Commit 17e433b5 ("KVM: Fix leak vCPU's VMCS value into other pCPU")
introduced vmx_dy_apicv_has_pending_interrupt() in order to determine
if a vCPU have a pending posted interrupt. This routine is used by
kvm_vcpu_on_spin() when searching for a a new runnable vCPU to schedule
on pCPU instead of a vCPU doing busy loop.

vmx_dy_apicv_has_pending_interrupt() determines if a
vCPU has a pending posted interrupt solely based on PID.ON. However,
when a vCPU is preempted, vmx_vcpu_pi_put() sets PID.SN which cause
raised posted interrupts to only set bit in PID.PIR without setting
PID.ON (and without sending notification vector), as depicted in VT-d
manual section 5.2.3 "Interrupt-Posting Hardware Operation".

Therefore, checking PID.ON is insufficient to determine if a vCPU has
pending posted interrupts and instead we should also check if there is
some bit set on PID.PIR if PID.SN=1.

Fixes: 17e433b5 ("KVM: Fix leak vCPU's VMCS value into other pCPU")
Reviewed-by: Jagannathan Raman <jag.raman@oracle.com>
Co-developed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The Outstanding Notification (ON) bit is part of the Posted Interrupt
Descriptor (PID) as opposed to the Posted Interrupts Register (PIR).
The latter is a bitmap for pending vectors.
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The three MSR lists(msrs_to_save[], emulated_msrs[] and
msr_based_features[]) are global arrays of kvm.ko, which are
adjusted (copy supported MSRs forward to override the unsupported MSRs)
when insmod kvm-{intel,amd}.ko, but it doesn't reset these three arrays
to their initial value when rmmod kvm-{intel,amd}.ko. Thus, at the next
installation, kvm-{intel,amd}.ko will do operations on the modified
arrays with some MSRs lost and some MSRs duplicated.

So define three constant arrays to hold the initial MSR lists and
initialize msrs_to_save[], emulated_msrs[] and msr_based_features[]
based on the constant arrays.

Cc: stable@vger.kernel.org
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
[Remove now useless conditionals. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Reported by syzkaller:

   =============================
   WARNING: suspicious RCU usage
   -----------------------------
   ./include/linux/kvm_host.h:536 suspicious rcu_dereference_check() usage!

   other info that might help us debug this:

   rcu_scheduler_active = 2, debug_locks = 1
   no locks held by repro_11/12688.

   stack backtrace:
   Call Trace:
    dump_stack+0x7d/0xc5
    lockdep_rcu_suspicious+0x123/0x170
    kvm_dev_ioctl+0x9a9/0x1260 [kvm]
    do_vfs_ioctl+0x1a1/0xfb0
    ksys_ioctl+0x6d/0x80
    __x64_sys_ioctl+0x73/0xb0
    do_syscall_64+0x108/0xaa0
    entry_SYSCALL_64_after_hwframe+0x49/0xbe

Commit a97b0e77 (kvm: call kvm_arch_destroy_vm if vm creation fails)
sets users_count to 1 before kvm_arch_init_vm(), however, if kvm_arch_init_vm()
fails, we need to decrease this count.  By moving it earlier, we can push
the decrease to out_err_no_arch_destroy_vm without introducing yet another
error label.

syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=15209b84e00000

Reported-by: syzbot+75475908cd0910f141ee@syzkaller.appspotmail.com
Fixes: a97b0e77 ("kvm: call kvm_arch_destroy_vm if vm creation fails")
Cc: Jim Mattson <jmattson@google.com>
Analyzed-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Reported by syzkaller:

    kasan: CONFIG_KASAN_INLINE enabled
    kasan: GPF could be caused by NULL-ptr deref or user memory access
    general protection fault: 0000 [#1] PREEMPT SMP KASAN
    CPU: 0 PID: 14727 Comm: syz-executor.3 Not tainted 5.4.0-rc4+ #0
    RIP: 0010:kvm_coalesced_mmio_init+0x5d/0x110 arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c:121
    Call Trace:
     kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3446 [inline]
     kvm_dev_ioctl+0x781/0x1490 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3494
     vfs_ioctl fs/ioctl.c:46 [inline]
     file_ioctl fs/ioctl.c:509 [inline]
     do_vfs_ioctl+0x196/0x1150 fs/ioctl.c:696
     ksys_ioctl+0x62/0x90 fs/ioctl.c:713
     __do_sys_ioctl fs/ioctl.c:720 [inline]
     __se_sys_ioctl fs/ioctl.c:718 [inline]
     __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:718
     do_syscall_64+0xca/0x5d0 arch/x86/entry/common.c:290
     entry_SYSCALL_64_after_hwframe+0x49/0xbe

Commit 9121923c ("kvm: Allocate memslots and buses before calling kvm_arch_init_vm")
moves memslots and buses allocations around, however, if kvm->srcu/irq_srcu fails
initialization, NULL will be returned instead of error code, NULL will not be intercepted
in kvm_dev_ioctl_create_vm() and be dereferenced by kvm_coalesced_mmio_init(), this patch
fixes it.

Moving the initialization is required anyway to avoid an incorrect synchronize_srcu that
was also reported by syzkaller:

 wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136
 __synchronize_srcu+0x197/0x250 kernel/rcu/srcutree.c:921
 synchronize_srcu_expedited kernel/rcu/srcutree.c:946 [inline]
 synchronize_srcu+0x239/0x3e8 kernel/rcu/srcutree.c:997
 kvm_page_track_unregister_notifier+0xe7/0x130 arch/x86/kvm/page_track.c:212
 kvm_mmu_uninit_vm+0x1e/0x30 arch/x86/kvm/mmu.c:5828
 kvm_arch_destroy_vm+0x4a2/0x5f0 arch/x86/kvm/x86.c:9579
 kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:702 [inline]

so do it.

Reported-by: syzbot+89a8060879fa0bd2db4f@syzkaller.appspotmail.com
Reported-by: syzbot+e27e7027eb2b80e44225@syzkaller.appspotmail.com
Fixes: 9121923c ("kvm: Allocate memslots and buses before calling kvm_arch_init_vm")
Cc: Jim Mattson <jmattson@google.com>
Cc: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Pull ARM SoC fixes from Olof Johansson:
 "A set of fixes that have trickled in over the last couple of weeks:

   - MAINTAINER update for Cavium/Marvell ThunderX2

   - stm32 tweaks to pinmux for Joystick/Camera, and RAM allocation for
     CAN interfaces

   - i.MX fixes for voltage regulator GPIO mappings, fixes voltage
     scaling issues

   - More i.MX fixes for various issues on i.MX eval boards: interrupt
     storm due to u-boot leaving pins in new states, fixing power button
     config, a couple of compatible-string corrections.

   - Powerdown and Suspend/Resume fixes for Allwinner A83-based tablets

   - A few documentation tweaks and a fix of a memory leak in the reset
     subsystem"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
  MAINTAINERS: update Cavium ThunderX2 maintainers
  ARM: dts: stm32: change joystick pinctrl definition on stm32mp157c-ev1
  ARM: dts: stm32: remove OV5640 pinctrl definition on stm32mp157c-ev1
  ARM: dts: stm32: Fix CAN RAM mapping on stm32mp157c
  ARM: dts: stm32: relax qspi pins slew-rate for stm32mp157
  arm64: dts: zii-ultra: fix ARM regulator GPIO handle
  ARM: sunxi: Fix CPU powerdown on A83T
  ARM: dts: sun8i-a83t-tbs-a711: Fix WiFi resume from suspend
  arm64: dts: imx8mn: fix compatible string for sdma
  arm64: dts: imx8mm: fix compatible string for sdma
  reset: fix reset_control_ops kerneldoc comment
  ARM: dts: imx6-logicpd: Re-enable SNVS power key
  soc: imx: gpc: fix initialiser format
  ARM: dts: imx6qdl-sabreauto: Fix storm of accelerometer interrupts
  arm64: dts: ls1028a: fix a compatible issue
  reset: fix reset_control_get_exclusive kerneldoc comment
  reset: fix reset_control_lookup kerneldoc comment
  reset: fix of_reset_control_get_count kerneldoc comment
  reset: fix of_reset_simple_xlate kerneldoc comment
  reset: Fix memory leak in reset_control_array_put()

Pull IIO fixes and staging driver from Greg KH:
 "Here is a mix of a number of IIO driver fixes for 5.4-rc7, and a whole
  new staging driver.

  The IIO fixes resolve some reported issues, all are tiny.

  The staging driver addition is the vboxsf filesystem, which is the
  VirtualBox guest shared folder code. Hans has been trying to get
  filesystem reviewers to review the code for many months now, and
  Christoph finally said to just merge it in staging now as it is
  stand-alone and the filesystem people can review it easier over time
  that way.

  I know it's late for this big of an addition, but it is stand-alone.

  The code has been in linux-next for a while, long enough to pick up a
  few tiny fixes for it already so people are looking at it.

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

* tag 'staging-5.4-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: Fix error return code in vboxsf_fill_super()
  staging: vboxsf: fix dereference of pointer dentry before it is null checked
  staging: vboxsf: Remove unused including <linux/version.h>
  staging: Add VirtualBox guest shared folder (vboxsf) support
  iio: adc: stm32-adc: fix stopping dma
  iio: imu: inv_mpu6050: fix no data on MPU6050
  iio: srf04: fix wrong limitation in distance measuring
  iio: imu: adis16480: make sure provided frequency is positive

Pull char/misc driver fixes from Greg KH:
 "Here are a number of late-arrival driver fixes for issues reported for
  some char/misc drivers for 5.4-rc7

  These all come from the different subsystem/driver maintainers as
  things that they had reports for and wanted to see fixed.

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

* tag 'char-misc-5.4-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  intel_th: pci: Add Jasper Lake PCH support
  intel_th: pci: Add Comet Lake PCH support
  intel_th: msu: Fix possible memory leak in mode_store()
  intel_th: msu: Fix overflow in shift of an unsigned int
  intel_th: msu: Fix missing allocation failure check on a kstrndup
  intel_th: msu: Fix an uninitialized mutex
  intel_th: gth: Fix the window switching sequence
  soundwire: slave: fix scanf format
  soundwire: intel: fix intel_register_dai PDI offsets and numbers
  interconnect: Add locking in icc_set_tag()
  interconnect: qcom: Fix icc_onecell_data allocation
  soundwire: depend on ACPI || OF
  soundwire: depend on ACPI
  thunderbolt: Drop unnecessary read when writing LC command in Ice Lake
  thunderbolt: Fix lockdep circular locking depedency warning
  thunderbolt: Read DP IN adapter first two dwords in one go

Pull configfs regression fix from Christoph Hellwig:
 "Fix a regression from this merge window in the configfs symlink
  handling (Honggang Li)"

* tag 'configfs-for-5.4-2' of git://git.infradead.org/users/hch/configfs:
  configfs: calculate the depth of parent item

Pull x86 fixes from Thomas Gleixner:
 "A small set of fixes for x86:

   - Make the tsc=reliable/nowatchdog command line parameter work again.
     It was broken with the introduction of the early TSC clocksource.

   - Prevent the evaluation of exception stacks before they are set up.
     This causes a crash in dumpstack because the stack walk termination
     gets screwed up.

   - Prevent a NULL pointer dereference in the rescource control file
     system.

   - Avoid bogus warnings about APIC id mismatch related to the LDR
     which can happen when the LDR is not in use and therefore not
     initialized. Only evaluate that when the APIC is in logical
     destination mode"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tsc: Respect tsc command line paraemeter for clocksource_tsc_early
  x86/dumpstack/64: Don't evaluate exception stacks before setup
  x86/apic/32: Avoid bogus LDR warnings
  x86/resctrl: Prevent NULL pointer dereference when reading mondata

Pull timer fixes from Thomas Gleixner:
 "A small set of fixes for timekeepoing and clocksource drivers:

   - VDSO data was updated conditional on the availability of a VDSO
     capable clocksource. This causes the VDSO functions which do not
     depend on a VDSO capable clocksource to operate on stale data.
     Always update unconditionally.

   - Prevent a double free in the mediatek driver

   - Use the proper helper in the sh_mtu2 driver so it won't attempt to
     initialize non-existing interrupts"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping/vsyscall: Update VDSO data unconditionally
  clocksource/drivers/sh_mtu2: Do not loop using platform_get_irq_by_name()
  clocksource/drivers/mediatek: Fix error handling

Pull scheduler fixes from Thomas Gleixner:
 "Two fixes for scheduler regressions:

   - Plug a subtle race condition which was introduced with the rework
     of the next task selection functionality. The change of task
     properties became unprotected which can be observed inconsistently
     causing state corruption.

   - A trivial compile fix for CONFIG_CGROUPS=n"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix pick_next_task() vs 'change' pattern race
  sched/core: Fix compilation error when cgroup not selected

Pull perf tooling fixes from Thomas Gleixner:

 - Fix the time sorting algorithm which was broken due to truncation of
   big numbers

 - Fix the python script generator fail caused by a broken tracepoint
   array iterator

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf tools: Fix time sorting
  perf tools: Remove unused trace_find_next_event()
  perf scripting engines: Iterate on tep event arrays directly

Pull irq fixlet from Thomas Gleixner:
 "A trivial fix for a kernel doc regression where an argument change was
  not reflected in the documentation"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irq/irqdomain: Update __irq_domain_alloc_fwnode() function documentation

Pull stacktrace fix from Thomas Gleixner:
 "A small fix for a stacktrace regression.

  Saving a stacktrace for a foreign task skipped an extra entry which
  makes e.g. the output of /proc/$PID/stack incomplete"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  stacktrace: Don't skip first entry on noncurrent tasks

Pull cifs fix from Steve French:
 "Small fix for an smb3 reconnect bug (also marked for stable)"

* tag '5.4-rc7-smb3-fix' of git://git.samba.org/sfrench/cifs-2.6:
  SMB3: Fix persistent handles reconnect

config option GENERIC_IO was removed but still selected by lib/kconfig
This patch finish the cleaning.

Fixes: 9de8da47 ("kconfig: kill off GENERIC_IO option")
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull pin control fixes from Linus Walleij:

 - Fix glitch risks in the Intel GPIO

 - Fix the Intel Cherryview valid irq mask calculation.

 - Allocate the Intel Cherryview irqchip dynamically.

 - Fix the valid mask init sequency on the ST STMFX driver.

* tag 'pinctrl-v5.4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  pinctrl: stmfx: fix valid_mask init sequence
  pinctrl: cherryview: Allocate IRQ chip dynamic
  pinctrl: cherryview: Fix irq_valid_mask calculation
  pinctrl: intel: Avoid potential glitches if pin is in GPIO mode

Pull btrfs fixes from David Sterba:
 "A few regressions and fixes for stable.

  Regressions:

   - fix a race leading to metadata space leak after task received a
     signal

   - un-deprecate 2 ioctls, marked as deprecated by mistake

  Fixes:

   - fix limit check for number of devices during chunk allocation

   - fix a race due to double evaluation of i_size_read inside max()
     macro, can cause a crash

   - remove wrong device id check in tree-checker"

* tag 'for-5.4-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: un-deprecate ioctls START_SYNC and WAIT_SYNC
  btrfs: save i_size to avoid double evaluation of i_size_read in compress_file_range
  Btrfs: fix race leading to metadata space leak after task received signal
  btrfs: tree-checker: Fix wrong check on max devid
  btrfs: Consider system chunk array size for new SYSTEM chunks

Pull watchdog fixes from Wim Van Sebroeck:

 - cpwd: fix build regression

 - pm8916_wdt: fix pretimeout registration flow

 - meson: Fix the wrong value of left time

 - imx_sc_wdt: Pretimeout should follow SCU firmware format

 - bd70528: Add MODULE_ALIAS to allow module auto loading

* tag 'linux-watchdog-5.4-rc7' of git://www.linux-watchdog.org/linux-watchdog:
  watchdog: bd70528: Add MODULE_ALIAS to allow module auto loading
  watchdog: imx_sc_wdt: Pretimeout should follow SCU firmware format
  watchdog: meson: Fix the wrong value of left time
  watchdog: pm8916_wdt: fix pretimeout registration flow
  watchdog: cpwd: fix build regression

Pull networking fixes from David Miller:

 1) BPF sample build fixes from Björn Töpel

 2) Fix powerpc bpf tail call implementation, from Eric Dumazet.

 3) DCCP leaks jiffies on the wire, fix also from Eric Dumazet.

 4) Fix crash in ebtables when using dnat target, from Florian Westphal.

 5) Fix port disable handling whne removing bcm_sf2 driver, from Florian
    Fainelli.

 6) Fix kTLS sk_msg trim on fallback to copy mode, from Jakub Kicinski.

 7) Various KCSAN fixes all over the networking, from Eric Dumazet.

 8) Memory leaks in mlx5 driver, from Alex Vesker.

 9) SMC interface refcounting fix, from Ursula Braun.

10) TSO descriptor handling fixes in stmmac driver, from Jose Abreu.

11) Add a TX lock to synchonize the kTLS TX path properly with crypto
    operations. From Jakub Kicinski.

12) Sock refcount during shutdown fix in vsock/virtio code, from Stefano
    Garzarella.

13) Infinite loop in Intel ice driver, from Colin Ian King.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (108 commits)
  ixgbe: need_wakeup flag might not be set for Tx
  i40e: need_wakeup flag might not be set for Tx
  igb/igc: use ktime accessors for skb->tstamp
  i40e: Fix for ethtool -m issue on X722 NIC
  iavf: initialize ITRN registers with correct values
  ice: fix potential infinite loop because loop counter being too small
  qede: fix NULL pointer deref in __qede_remove()
  net: fix data-race in neigh_event_send()
  vsock/virtio: fix sock refcnt holding during the shutdown
  net: ethernet: octeon_mgmt: Account for second possible VLAN header
  mac80211: fix station inactive_time shortly after boot
  net/fq_impl: Switch to kvmalloc() for memory allocation
  mac80211: fix ieee80211_txq_setup_flows() failure path
  ipv4: Fix table id reference in fib_sync_down_addr
  ipv6: fixes rt6_probe() and fib6_nh->last_probe init
  net: hns: Fix the stray netpoll locks causing deadlock in NAPI path
  net: usb: qmi_wwan: add support for DW5821e with eSIM support
  CDC-NCM: handle incomplete transfer of MTU
  nfc: netlink: fix double device reference drop
  NFC: st21nfca: fix double free
  ...

Pull block fixes from Jens Axboe:

 - Two NVMe device removal crash fixes, and a compat fixup for for an
   ioctl that was introduced in this release (Anton, Charles, Max - via
   Keith)

 - Missing error path mutex unlock for drbd (Dan)

 - cgroup writeback fixup on dead memcg (Tejun)

 - blkcg online stats print fix (Tejun)

* tag 'for-linus-2019-11-08' of git://git.kernel.dk/linux-block:
  cgroup,writeback: don't switch wbs immediately on dead wbs if the memcg is dead
  block: drbd: remove a stray unlock in __drbd_send_protocol()
  blkcg: make blkcg_print_stat() print stats only for online blkgs
  nvme: change nvme_passthru_cmd64 to explicitly mark rsvd
  nvme-multipath: fix crash in nvme_mpath_clear_ctrl_paths
  nvme-rdma: fix a segmentation fault during module unload

Jeff Kirsher says:

====================
Intel Wired LAN Driver Fixes 2019-11-08

This series contains fixes to igb, igc, ixgbe, i40e, iavf and ice
drivers.

Colin Ian King fixes a potentially wrap-around counter in a for-loop.

Nick fixes the default ITR values for the iavf driver to 50 usecs
interval.

Arkadiusz fixes 'ethtool -m' for X722 devices where the correct value
cannot be obtained from the firmware, so add X722 to the check to ensure
the wrong value is not returned.

Jake fixes igb and igc drivers in their implementation of launch time
support by declaring skb->tstamp value as ktime_t instead of s64.

Magnus fixes ixgbe and i40e where the need_wakeup flag for transmit may
not be set for AF_XDP sockets that are only used to send packets.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The need_wakeup flag for Tx might not be set for AF_XDP sockets that
are only used to send packets. This happens if there is at least one
outstanding packet that has not been completed by the hardware and we
get that corresponding completion (which will not generate an
interrupt since interrupts are disabled in the napi poll loop) between
the time we stopped processing the Tx completions and interrupts are
enabled again. In this case, the need_wakeup flag will have been
cleared at the end of the Tx completion processing as we believe we
will get an interrupt from the outstanding completion at a later point
in time. But if this completion interrupt occurs before interrupts
are enable, we lose it and should at that point really have set the
need_wakeup flag since there are no more outstanding completions that
can generate an interrupt to continue the processing. When this
happens, user space will see a Tx queue need_wakeup of 0 and skip
issuing a syscall, which means will never get into the Tx processing
again and we have a deadlock.

This patch introduces a quick fix for this issue by just setting the
need_wakeup flag for Tx to 1 all the time. I am working on a proper
fix for this that will toggle the flag appropriately, but it is more
challenging than I anticipated and I am afraid that this patch will
not be completed before the merge window closes, therefore this easier
fix for now. This fix has a negative performance impact in the range
of 0% to 4%. Towards the higher end of the scale if you have driver
and application on the same core and issue a lot of packets, and
towards no negative impact if you use two cores, lower transmission
speeds and/or a workload that also receives packets.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

The need_wakeup flag for Tx might not be set for AF_XDP sockets that
are only used to send packets. This happens if there is at least one
outstanding packet that has not been completed by the hardware and we
get that corresponding completion (which will not generate an
interrupt since interrupts are disabled in the napi poll loop) between
the time we stopped processing the Tx completions and interrupts are
enabled again. In this case, the need_wakeup flag will have been
cleared at the end of the Tx completion processing as we believe we
will get an interrupt from the outstanding completion at a later point
in time. But if this completion interrupt occurs before interrupts
are enable, we lose it and should at that point really have set the
need_wakeup flag since there are no more outstanding completions that
can generate an interrupt to continue the processing. When this
happens, user space will see a Tx queue need_wakeup of 0 and skip
issuing a syscall, which means will never get into the Tx processing
again and we have a deadlock.

This patch introduces a quick fix for this issue by just setting the
need_wakeup flag for Tx to 1 all the time. I am working on a proper
fix for this that will toggle the flag appropriately, but it is more
challenging than I anticipated and I am afraid that this patch will
not be completed before the merge window closes, therefore this easier
fix for now. This fix has a negative performance impact in the range
of 0% to 4%. Towards the higher end of the scale if you have driver
and application on the same core and issue a lot of packets, and
towards no negative impact if you use two cores, lower transmission
speeds and/or a workload that also receives packets.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

When implementing launch time support in the igb and igc drivers, the
skb->tstamp value is assumed to be a s64, but it's declared as a ktime_t
value.

Although ktime_t is typedef'd to s64 it wasn't always, and the kernel
provides accessors for ktime_t values.

Use the ktime_to_timespec64 and ktime_set accessors instead of directly
assuming that the variable is always an s64.

This improves portability if the code is ever moved to another kernel
version, or if the definition of ktime_t ever changes again in the
future.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

This patch contains fix for a problem with command:
'ethtool -m <dev>'
which breaks functionality of:
'ethtool <dev>'
when called on X722 NIC

Disallowed update of link phy_types on X722 NIC
Currently correct value cannot be obtained from FW
Previously wrong value returned by FW was used and was
a root cause for incorrect output of 'ethtool <dev>' command
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Since commit 92418fb1 ("i40e/i40evf: Use usec value instead of reg
value for ITR defines") the driver tracks the interrupt throttling
intervals in single usec units, although the actual ITRN registers are
programmed in 2 usec units. Most register programming flows in the driver
correctly handle the conversion, although it is currently not applied when
the registers are initialized to their default values. Most of the time
this doesn't present a problem since the default values are usually
immediately overwritten through the standard adaptive throttling mechanism,
or updated manually by the user, but if adaptive throttling is disabled and
the interval values are left alone then the incorrect value will persist.

Since the intended default interval of 50 usecs (vs. 100 usecs as
programmed) performs better for most traffic workloads, this can lead to
performance regressions.

This patch adds the correct conversion when writing the initial values to
the ITRN registers.
Signed-off-by: Nicholas Nunley <nicholas.d.nunley@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Currently the for-loop counter i is a u8 however it is being checked
against a maximum value hw->num_tx_sched_layers which is a u16. Hence
there is a potential wrap-around of counter i back to zero if
hw->num_tx_sched_layers is greater than 255.  Fix this by making i
a u16.

Addresses-Coverity: ("Infinite loop")
Fixes: b36c598c ("ice: Updates to Tx scheduler code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

While rebooting the system with SR-IOV vfs enabled leads
to below crash due to recurrence of __qede_remove() on the VF
devices (first from .shutdown() flow of the VF itself and
another from PF's .shutdown() flow executing pci_disable_sriov())

This patch adds a safeguard in __qede_remove() flow to fix this,
so that driver doesn't attempt to remove "already removed" devices.

[  194.360134] BUG: unable to handle kernel NULL pointer dereference at 00000000000008dc
[  194.360227] IP: [<ffffffffc03553c4>] __qede_remove+0x24/0x130 [qede]
[  194.360304] PGD 0
[  194.360325] Oops: 0000 [#1] SMP
[  194.360360] Modules linked in: tcp_lp fuse tun bridge stp llc devlink bonding ip_set nfnetlink ib_isert iscsi_target_mod ib_srpt target_core_mod ib_srp scsi_transport_srp scsi_tgt ib_ipoib ib_umad rpcrdma sunrpc rdma_ucm ib_uverbs ib_iser rdma_cm iw_cm ib_cm libiscsi scsi_transport_iscsi dell_smbios iTCO_wdt iTCO_vendor_support dell_wmi_descriptor dcdbas vfat fat pcc_cpufreq skx_edac intel_powerclamp coretemp intel_rapl iosf_mbi kvm_intel kvm irqbypass crc32_pclmul ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd qedr ib_core pcspkr ses enclosure joydev ipmi_ssif sg i2c_i801 lpc_ich mei_me mei wmi ipmi_si ipmi_devintf ipmi_msghandler tpm_crb acpi_pad acpi_power_meter xfs libcrc32c sd_mod crc_t10dif crct10dif_generic crct10dif_pclmul crct10dif_common crc32c_intel mgag200
[  194.361044]  qede i2c_algo_bit drm_kms_helper qed syscopyarea sysfillrect nvme sysimgblt fb_sys_fops ttm nvme_core mpt3sas crc8 ptp drm pps_core ahci raid_class scsi_transport_sas libahci libata drm_panel_orientation_quirks nfit libnvdimm dm_mirror dm_region_hash dm_log dm_mod [last unloaded: ip_tables]
[  194.361297] CPU: 51 PID: 7996 Comm: reboot Kdump: loaded Not tainted 3.10.0-1062.el7.x86_64 #1
[  194.361359] Hardware name: Dell Inc. PowerEdge MX840c/0740HW, BIOS 2.4.6 10/15/2019
[  194.361412] task: ffff9cea9b360000 ti: ffff9ceabebdc000 task.ti: ffff9ceabebdc000
[  194.361463] RIP: 0010:[<ffffffffc03553c4>]  [<ffffffffc03553c4>] __qede_remove+0x24/0x130 [qede]
[  194.361534] RSP: 0018:ffff9ceabebdfac0  EFLAGS: 00010282
[  194.361570] RAX: 0000000000000000 RBX: ffff9cd013846098 RCX: 0000000000000000
[  194.361621] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9cd013846098
[  194.361668] RBP: ffff9ceabebdfae8 R08: 0000000000000000 R09: 0000000000000000
[  194.361715] R10: 00000000bfe14201 R11: ffff9ceabfe141e0 R12: 0000000000000000
[  194.361762] R13: ffff9cd013846098 R14: 0000000000000000 R15: ffff9ceab5e48000
[  194.361810] FS:  00007f799c02d880(0000) GS:ffff9ceacb0c0000(0000) knlGS:0000000000000000
[  194.361865] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  194.361903] CR2: 00000000000008dc CR3: 0000001bdac76000 CR4: 00000000007607e0
[  194.361953] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  194.362002] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  194.362051] PKRU: 55555554
[  194.362073] Call Trace:
[  194.362109]  [<ffffffffc0355500>] qede_remove+0x10/0x20 [qede]
[  194.362180]  [<ffffffffb97d0f3e>] pci_device_remove+0x3e/0xc0
[  194.362240]  [<ffffffffb98b3c52>] __device_release_driver+0x82/0xf0
[  194.362285]  [<ffffffffb98b3ce3>] device_release_driver+0x23/0x30
[  194.362343]  [<ffffffffb97c86d4>] pci_stop_bus_device+0x84/0xa0
[  194.362388]  [<ffffffffb97c87e2>] pci_stop_and_remove_bus_device+0x12/0x20
[  194.362450]  [<ffffffffb97f153f>] pci_iov_remove_virtfn+0xaf/0x160
[  194.362496]  [<ffffffffb97f1aec>] sriov_disable+0x3c/0xf0
[  194.362534]  [<ffffffffb97f1bc3>] pci_disable_sriov+0x23/0x30
[  194.362599]  [<ffffffffc02f83c3>] qed_sriov_disable+0x5e3/0x650 [qed]
[  194.362658]  [<ffffffffb9622df6>] ? kfree+0x106/0x140
[  194.362709]  [<ffffffffc02cc0c0>] ? qed_free_stream_mem+0x70/0x90 [qed]
[  194.362754]  [<ffffffffb9622df6>] ? kfree+0x106/0x140
[  194.362803]  [<ffffffffc02cd659>] qed_slowpath_stop+0x1a9/0x1d0 [qed]
[  194.362854]  [<ffffffffc035544e>] __qede_remove+0xae/0x130 [qede]
[  194.362904]  [<ffffffffc03554e0>] qede_shutdown+0x10/0x20 [qede]
[  194.362956]  [<ffffffffb97cf90a>] pci_device_shutdown+0x3a/0x60
[  194.363010]  [<ffffffffb98b180b>] device_shutdown+0xfb/0x1f0
[  194.363066]  [<ffffffffb94b66c6>] kernel_restart_prepare+0x36/0x40
[  194.363107]  [<ffffffffb94b66e2>] kernel_restart+0x12/0x60
[  194.363146]  [<ffffffffb94b6959>] SYSC_reboot+0x229/0x260
[  194.363196]  [<ffffffffb95f200d>] ? handle_mm_fault+0x39d/0x9b0
[  194.363253]  [<ffffffffb942b621>] ? __switch_to+0x151/0x580
[  194.363304]  [<ffffffffb9b7ec28>] ? __schedule+0x448/0x9c0
[  194.363343]  [<ffffffffb94b69fe>] SyS_reboot+0xe/0x10
[  194.363387]  [<ffffffffb9b8bede>] system_call_fastpath+0x25/0x2a
[  194.363430] Code: f9 e9 37 ff ff ff 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 4c 8d af 98 00 00 00 41 54 4c 89 ef 41 89 f4 53 e8 4c e4 55 f9 <80> b8 dc 08 00 00 01 48 89 c3 4c 8d b8 c0 08 00 00 4c 8b b0 c0
[  194.363712] RIP  [<ffffffffc03553c4>] __qede_remove+0x24/0x130 [qede]
[  194.363764]  RSP <ffff9ceabebdfac0>
[  194.363791] CR2: 00000000000008dc
Signed-off-by: Manish Chopra <manishc@marvell.com>
Signed-off-by: Ariel Elior <aelior@marvell.com>
Signed-off-by: Sudarsana Kalluru <skalluru@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

KCSAN reported the following data-race [1]

The fix will also prevent the compiler from optimizing out
the condition.

[1]

BUG: KCSAN: data-race in neigh_resolve_output / neigh_resolve_output

write to 0xffff8880a41dba78 of 8 bytes by interrupt on cpu 1:
 neigh_event_send include/net/neighbour.h:443 [inline]
 neigh_resolve_output+0x78/0x480 net/core/neighbour.c:1474
 neigh_output include/net/neighbour.h:511 [inline]
 ip_finish_output2+0x4af/0xe40 net/ipv4/ip_output.c:228
 __ip_finish_output net/ipv4/ip_output.c:308 [inline]
 __ip_finish_output+0x23a/0x490 net/ipv4/ip_output.c:290
 ip_finish_output+0x41/0x160 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip_output+0xdf/0x210 net/ipv4/ip_output.c:432
 dst_output include/net/dst.h:436 [inline]
 ip_local_out+0x74/0x90 net/ipv4/ip_output.c:125
 __ip_queue_xmit+0x3a8/0xa40 net/ipv4/ip_output.c:532
 ip_queue_xmit+0x45/0x60 include/net/ip.h:237
 __tcp_transmit_skb+0xe81/0x1d60 net/ipv4/tcp_output.c:1169
 tcp_transmit_skb net/ipv4/tcp_output.c:1185 [inline]
 __tcp_retransmit_skb+0x4bd/0x15f0 net/ipv4/tcp_output.c:2976
 tcp_retransmit_skb+0x36/0x1a0 net/ipv4/tcp_output.c:2999
 tcp_retransmit_timer+0x719/0x16d0 net/ipv4/tcp_timer.c:515
 tcp_write_timer_handler+0x42d/0x510 net/ipv4/tcp_timer.c:598
 tcp_write_timer+0xd1/0xf0 net/ipv4/tcp_timer.c:618

read to 0xffff8880a41dba78 of 8 bytes by interrupt on cpu 0:
 neigh_event_send include/net/neighbour.h:442 [inline]
 neigh_resolve_output+0x57/0x480 net/core/neighbour.c:1474
 neigh_output include/net/neighbour.h:511 [inline]
 ip_finish_output2+0x4af/0xe40 net/ipv4/ip_output.c:228
 __ip_finish_output net/ipv4/ip_output.c:308 [inline]
 __ip_finish_output+0x23a/0x490 net/ipv4/ip_output.c:290
 ip_finish_output+0x41/0x160 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip_output+0xdf/0x210 net/ipv4/ip_output.c:432
 dst_output include/net/dst.h:436 [inline]
 ip_local_out+0x74/0x90 net/ipv4/ip_output.c:125
 __ip_queue_xmit+0x3a8/0xa40 net/ipv4/ip_output.c:532
 ip_queue_xmit+0x45/0x60 include/net/ip.h:237
 __tcp_transmit_skb+0xe81/0x1d60 net/ipv4/tcp_output.c:1169
 tcp_transmit_skb net/ipv4/tcp_output.c:1185 [inline]
 __tcp_retransmit_skb+0x4bd/0x15f0 net/ipv4/tcp_output.c:2976
 tcp_retransmit_skb+0x36/0x1a0 net/ipv4/tcp_output.c:2999
 tcp_retransmit_timer+0x719/0x16d0 net/ipv4/tcp_timer.c:515
 tcp_write_timer_handler+0x42d/0x510 net/ipv4/tcp_timer.c:598

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'pwm/for-5.4-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm fix from Thierry Reding:
 "One more fix to keep a reference to the driver's module as long as
  there are users of the PWM exposed by the driver"

* tag 'pwm/for-5.4-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
  pwm: bcm-iproc: Prevent unloading the driver module while in use

Commit 67692435 ("sched: Rework pick_next_task() slow-path")
inadvertly introduced a race because it changed a previously
unexplored dependency between dropping the rq->lock and
sched_class::put_prev_task().

The comments about dropping rq->lock, in for example
newidle_balance(), only mentions the task being current and ->on_cpu
being set. But when we look at the 'change' pattern (in for example
sched_setnuma()):

	queued = task_on_rq_queued(p); /* p->on_rq == TASK_ON_RQ_QUEUED */
	running = task_current(rq, p); /* rq->curr == p */

	if (queued)
		dequeue_task(...);
	if (running)
		put_prev_task(...);

	/* change task properties */

	if (queued)
		enqueue_task(...);
	if (running)
		set_next_task(...);

It becomes obvious that if we do this after put_prev_task() has
already been called on @p, things go sideways. This is exactly what
the commit in question allows to happen when it does:

	prev->sched_class->put_prev_task(rq, prev, rf);
	if (!rq->nr_running)
		newidle_balance(rq, rf);

The newidle_balance() call will drop rq->lock after we've called
put_prev_task() and that allows the above 'change' pattern to
interleave and mess up the state.

Furthermore, it turns out we lost the RT-pull when we put the last DL
task.

Fix both problems by extracting the balancing from put_prev_task() and
doing a multi-class balance() pass before put_prev_task().

Fixes: 67692435 ("sched: Rework pick_next_task() slow-path")
Reported-by: Quentin Perret <qperret@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Quentin Perret <qperret@google.com>
Tested-by: Valentin Schneider <valentin.schneider@arm.com>

When cgroup is disabled the following compilation error was hit

	kernel/sched/core.c: In function ‘uclamp_update_active_tasks’:
	kernel/sched/core.c:1081:23: error: storage size of ‘it’ isn’t known
	  struct css_task_iter it;
			       ^~
	kernel/sched/core.c:1084:2: error: implicit declaration of function ‘css_task_iter_start’; did you mean ‘__sg_page_iter_start’? [-Werror=implicit-function-declaration]
	  css_task_iter_start(css, 0, &it);
	  ^~~~~~~~~~~~~~~~~~~
	  __sg_page_iter_start
	kernel/sched/core.c:1085:14: error: implicit declaration of function ‘css_task_iter_next’; did you mean ‘__sg_page_iter_next’? [-Werror=implicit-function-declaration]
	  while ((p = css_task_iter_next(&it))) {
		      ^~~~~~~~~~~~~~~~~~
		      __sg_page_iter_next
	kernel/sched/core.c:1091:2: error: implicit declaration of function ‘css_task_iter_end’; did you mean ‘get_task_cred’? [-Werror=implicit-function-declaration]
	  css_task_iter_end(&it);
	  ^~~~~~~~~~~~~~~~~
	  get_task_cred
	kernel/sched/core.c:1081:23: warning: unused variable ‘it’ [-Wunused-variable]
	  struct css_task_iter it;
			       ^~
	cc1: some warnings being treated as errors
	make[2]: *** [kernel/sched/core.o] Error 1

Fix by protetion uclamp_update_active_tasks() with
CONFIG_UCLAMP_TASK_GROUP

Fixes: babbe170 ("sched/uclamp: Update CPU's refcount on TG's clamp changes")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Patrick Bellasi <patrick.bellasi@matbug.net>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Ben Segall <bsegall@google.com>
Link: https://lkml.kernel.org/r/20191105112212.596-1-qais.yousef@arm.com

cgroup writeback tries to refresh the associated wb immediately if the
current wb is dead.  This is to avoid keeping issuing IOs on the stale
wb after memcg - blkcg association has changed (ie. when blkcg got
disabled / enabled higher up in the hierarchy).

Unfortunately, the logic gets triggered spuriously on inodes which are
associated with dead cgroups.  When the logic is triggered on dead
cgroups, the attempt fails only after doing quite a bit of work
allocating and initializing a new wb.

While c3aab9a0 ("mm/filemap.c: don't initiate writeback if mapping
has no dirty pages") alleviated the issue significantly as it now only
triggers when the inode has dirty pages.  However, the condition can
still be triggered before the inode is switched to a different cgroup
and the logic simply doesn't make sense.

Skip the immediate switching if the associated memcg is dying.

This is a simplified version of the following two patches:

 * https://lore.kernel.org/linux-mm/20190513183053.GA73423@dennisz-mbp/
 * http://lkml.kernel.org/r/156355839560.2063.5265687291430814589.stgit@buzz

Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Fixes: e8a7abf5 ("writeback: disassociate inodes from dying bdi_writebacks")
Acked-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull ceph fixes from Ilya Dryomov:
 "Some late-breaking dentry handling fixes from Al and Jeff, a patch to
  further restrict copy_file_range() to avoid potential data corruption
  from Luis and a fix for !CONFIG_CEPH_FSCACHE kernels.

  Everything but the fscache fix is marked for stable"

* tag 'ceph-for-5.4-rc7' of git://github.com/ceph/ceph-client:
  ceph: return -EINVAL if given fsc mount option on kernel w/o support
  ceph: don't allow copy_file_range when stripe_count != 1
  ceph: don't try to handle hashed dentries in non-O_CREAT atomic_open
  ceph: add missing check in d_revalidate snapdir handling
  ceph: fix RCU case handling in ceph_d_revalidate()
  ceph: fix use-after-free in __ceph_remove_cap()