R-Car D3 has only one SDHI controller.
Signed-off-by: NUlrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Differs from other Gen3 SoCs in that each controller only supports eight
channels.
Signed-off-by: NUlrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

ULCB-KF has a USB2.0 dual-role channel (CN13).
This adds dr_mode property for USB2.0 channel 0 (EHCI/OHCI and HS-USB)
as "otg".
Signed-off-by: NVladimir Barinov <vladimir.barinov@cogentembedded.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

This supports USB2 PHY channel #0 on ULCB Kingfisher board

The dedicated USB0_PWEN pin is used to control CN13 VBUS source from U43
power supply.
MAX3355 can also provide VBUS, hence it should be disabled via OTG_OFFVBUSn
node coming from gpio expander TCA9539.
Set MAX3355 enabled using OTG_EXTLPn node to be able to read OTG ID of
CN13.
Signed-off-by: NVladimir Barinov <vladimir.barinov@cogentembedded.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Enable the r8a7795 device nodes for IPMMU-DS0, IPMMU-DS1, IPMMU-MP,
IPMMU-VI0, IPMMU-VC0 and the shared IPMMU-MM device.
Signed-off-by: NMagnus Damm <damm+renesas@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>

Add IPMMU-DS0 to the Ethernet-AVB device node.

Based on work by Magnus Damm for the r8a7795.
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>

Hook up the FCPVI devices to allow use of VSPI with IPMMU-VC0.

Based on work for the r8a7795 by Magnus Damm.
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>

Hook up the FCPF devices to allow use of FDP1 with IPMMU-VI0.

Based on work by Magnus Damm for the r8a7795.
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>

Hook up r8a7796 Audio-DMAC nodes to the IPMMU-MP.

Based on work for the r8a7795 by Magnus Damm.
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>

Hook up r8a7796 DMAC nodes to the IPMMUs. In particular SYS-DMAC0
gets tied to IPMMU-DS0, and SYS-DMAC1 and SYS-DMAC2 get tied to IPMMU-DS1.
Signed-off-by: NMagnus Damm <damm+renesas@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>

Add r8a7796 IPMMU nodes and keep all disabled by default.
Signed-off-by: NMagnus Damm <damm+renesas@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>

Add initial support for the Renesas Salvator-XS (Salvator-X 2nd version)
development board equipped with an R-Car M3-W SiP.

Based on work for the Salvator-X and -XS boards with M3-W resp. H3 SiPs.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Enable the Watchdog Timer (WDT) controller on the Renesas Eagle
board equipped with an R-Car V3M (r8a77970) SoC.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Add a device node for the Watchdog Timer (WDT) controller on the
Renesas R-Car V3M (r8a77970) SoC.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Use newly added R-Car SDHI Gen3 fallback compat string
in the DT of the r8a7796 SoC.

This should have no run-time effect as the driver matches against
the per-SoC compat string before considering the fallback compat string.
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Use newly added R-Car SDHI Gen3 fallback compat string
in the DT of the r8a7795 SoC.

This should have no run-time effect as the driver matches against
the per-SoC compat string before considering the fallback compat string.
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

These boards are known to have eMMC issues with the default driver type.
Specify a working one.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Pull ARM fixes from Russell King:

 - LPAE fixes for kernel-readonly regions

 - Fix for get_user_pages_fast on LPAE systems

 - avoid tying decompressor to a particular platform if DEBUG_LL is
   enabled

 - BUG if we attempt to return to userspace but the to-be-restored PSR
   value keeps us in privileged mode (defeating an issue that ftracetest
   found)

* 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: BUG if jumping to usermode address in kernel mode
  ARM: 8722/1: mm: make STRICT_KERNEL_RWX effective for LPAE
  ARM: 8721/1: mm: dump: check hardware RO bit for LPAE
  ARM: make decompressor debug output user selectable
  ARM: fix get_user_pages_fast

Pull irq fixes from Thomas Glexiner:

 - unbreak the irq trigger type check for legacy platforms

 - a handful fixes for ARM GIC v3/4 interrupt controllers

 - a few trivial fixes all over the place

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq/matrix: Make - vs ?: Precedence explicit
  irqchip/imgpdc: Use resource_size function on resource object
  irqchip/qcom: Fix u32 comparison with value less than zero
  irqchip/exiu: Fix return value check in exiu_init()
  irqchip/gic-v3-its: Remove artificial dependency on PCI
  irqchip/gic-v4: Add forward definition of struct irq_domain_ops
  irqchip/gic-v3: pr_err() strings should end with newlines
  irqchip/s3c24xx: pr_err() strings should end with newlines
  irqchip/gic-v3: Fix ppi-partitions lookup
  irqchip/gic-v4: Clear IRQ_DISABLE_UNLAZY again if mapping fails
  genirq: Track whether the trigger type has been set

Pull misc x86 fixes from Ingo Molnar:
 - topology enumeration fixes
 - KASAN fix
 - two entry fixes (not yet the big series related to KASLR)
 - remove obsolete code
 - instruction decoder fix
 - better /dev/mem sanity checks, hopefully working better this time
 - pkeys fixes
 - two ACPI fixes
 - 5-level paging related fixes
 - UMIP fixes that should make application visible faults more debuggable
 - boot fix for weird virtualization environment

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  x86/decoder: Add new TEST instruction pattern
  x86/PCI: Remove unused HyperTransport interrupt support
  x86/umip: Fix insn_get_code_seg_params()'s return value
  x86/boot/KASLR: Remove unused variable
  x86/entry/64: Add missing irqflags tracing to native_load_gs_index()
  x86/mm/kasan: Don't use vmemmap_populate() to initialize shadow
  x86/entry/64: Fix entry_SYSCALL_64_after_hwframe() IRQ tracing
  x86/pkeys/selftests: Fix protection keys write() warning
  x86/pkeys/selftests: Rename 'si_pkey' to 'siginfo_pkey'
  x86/mpx/selftests: Fix up weird arrays
  x86/pkeys: Update documentation about availability
  x86/umip: Print a warning into the syslog if UMIP-protected instructions are used
  x86/smpboot: Fix __max_logical_packages estimate
  x86/topology: Avoid wasting 128k for package id array
  perf/x86/intel/uncore: Cache logical pkg id in uncore driver
  x86/acpi: Reduce code duplication in mp_override_legacy_irq()
  x86/acpi: Handle SCI interrupts above legacy space gracefully
  x86/boot: Fix boot failure when SMP MP-table is based at 0
  x86/mm: Limit mmap() of /dev/mem to valid physical addresses
  x86/selftests: Add test for mapping placement for 5-level paging
  ...

Pull scheduler fixes from Ingo Molnar:
 "Misc fixes: a documentation fix, a Sparse warning fix and a debugging
  fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/debug: Fix task state recording/printout
  sched/deadline: Don't use dubious signed bitfields
  sched/deadline: Fix the description of runtime accounting in the documentation

Pull perf fixes from Ingo Molnar:
 "Misc fixes: two PMU driver fixes and a memory leak fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix memory leak triggered by perf --namespace
  perf/x86/intel/uncore: Add event constraint for BDX PCU
  perf/x86/intel: Hide TSX events when RTM is not supported

Pull static key fix from Ingo Molnar:
 "Fix a boot warning related to bad init ordering of the static keys
  self-test"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  jump_label: Invoke jump_label_test() via early_initcall()

Pull objtool fixes from Ingo Molnar:
 "A handful of objtool fixes, most of them related to making the UAPI
  header-syncing warnings easier to read and easier to act upon"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tools/headers: Sync objtool UAPI header
  objtool: Fix cross-build
  objtool: Move kernel headers/code sync check to a script
  objtool: Move synced files to their original relative locations
  objtool: Make unreachable annotation inline asms explicitly volatile
  objtool: Add a comment for the unreachable annotation macros

Detect if we are returning to usermode via the normal kernel exit paths
but the saved PSR value indicates that we are in kernel mode.  This
could occur due to corrupted stack state, which has been observed with
"ftracetest".

This ensures that we catch the problem case before we get to user code.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

Pull timer updates from Thomas Gleixner:

 - The final conversion of timer wheel timers to timer_setup().

   A few manual conversions and a large coccinelle assisted sweep and
   the removal of the old initialization mechanisms and the related
   code.

 - Remove the now unused VSYSCALL update code

 - Fix permissions of /proc/timer_list. I still need to get rid of that
   file completely

 - Rename a misnomed clocksource function and remove a stale declaration

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
  m68k/macboing: Fix missed timer callback assignment
  treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts
  timer: Remove redundant __setup_timer*() macros
  timer: Pass function down to initialization routines
  timer: Remove unused data arguments from macros
  timer: Switch callback prototype to take struct timer_list * argument
  timer: Pass timer_list pointer to callbacks unconditionally
  Coccinelle: Remove setup_timer.cocci
  timer: Remove setup_*timer() interface
  timer: Remove init_timer() interface
  treewide: setup_timer() -> timer_setup() (2 field)
  treewide: setup_timer() -> timer_setup()
  treewide: init_timer() -> setup_timer()
  treewide: Switch DEFINE_TIMER callbacks to struct timer_list *
  s390: cmm: Convert timers to use timer_setup()
  lightnvm: Convert timers to use timer_setup()
  drivers/net: cris: Convert timers to use timer_setup()
  drm/vc4: Convert timers to use timer_setup()
  block/laptop_mode: Convert timers to use timer_setup()
  net/atm/mpc: Avoid open-coded assignment of timer callback function
  ...

Pull ARC updates from Vineet Gupta:

 - more changes for HS48 cores: supporting MMUv5, detecting new
   micro-arch gizmos

 - axs10x platform wiring up reset driver merged in this cycle

 - ARC perf driver optimizations

* tag 'arc-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: perf: avoid vmalloc backed mmap
  ARCv2: perf: optimize given that num counters <= 32
  ARCv2: perf: tweak overflow interrupt
  ARC: [plat-axs10x] DTS: Add reset controller node to manage ethernet reset
  ARCv2: boot log: updates for HS48: dual-issue, ECC, Loop Buffer
  ARCv2: Accomodate HS48 MMUv5 by relaxing MMU ver checking
  ARC: [plat-axs10x] auto-select AXS101 or AXS103 given the  ISA config

Pull more Kbuild updates from Masahiro Yamada:

 - use 'pwd' instead of '/bin/pwd' for portability

 - clean up Makefiles

 - fix ld-option for clang

 - fix malloc'ed data size in Kconfig

 - fix parallel building along with coccicheck

 - fix a minor issue of package building

 - prompt to use "rpm-pkg" instead of "rpm"

 - clean up *.i and *.lst patterns by "make clean"

* tag 'kbuild-v4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: drop $(extra-y) from real-objs-y
  kbuild: clean up *.i and *.lst patterns by make clean
  kbuild: rpm: prompt to use "rpm-pkg" if "rpm" target is used
  kbuild: pkg: use --transform option to prefix paths in tar
  coccinelle: fix parallel build with CHECK=scripts/coccicheck
  kconfig/symbol.c: use correct pointer type argument for sizeof
  kbuild: Set KBUILD_CFLAGS before incl. arch Makefile
  kbuild: remove all dummy assignments to obj-
  kbuild: create built-in.o automatically if parent directory wants it
  kbuild: /bin/pwd -> pwd

Pull AFS fixes from David Howells:

 - Make AFS file locking work again.

 - Don't write to a page that's being written out, but wait for it to
   complete.

 - Do d_drop() and d_add() in the right places.

 - Put keys on error paths.

 - Remove some redundant code.

* tag 'afs-fixes-20171124' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: remove redundant assignment of dvnode to itself
  afs: cell: Remove unnecessary code in afs_lookup_cell
  afs: Fix signal handling in some file ops
  afs: Fix some dentry handling in dir ops and missing key_puts
  afs: Make afs_write_begin() avoid writing to a page that's being stored
  afs: Fix file locking

Pull KVM updates from Radim Krčmář:
 "Trimmed second batch of KVM changes for Linux 4.15:

   - GICv4 Support for KVM/ARM

   - re-introduce support for CPUs without virtual NMI (cc stable) and
     allow testing of KVM without virtual NMI on available CPUs

   - fix long-standing performance issues with assigned devices on AMD
     (cc stable)"

* tag 'kvm-4.15-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (30 commits)
  kvm: vmx: Allow disabling virtual NMI support
  kvm: vmx: Reinstate support for CPUs without virtual NMI
  KVM: SVM: obey guest PAT
  KVM: arm/arm64: Don't queue VLPIs on INV/INVALL
  KVM: arm/arm64: Fix GICv4 ITS initialization issues
  KVM: arm/arm64: GICv4: Theory of operations
  KVM: arm/arm64: GICv4: Enable VLPI support
  KVM: arm/arm64: GICv4: Prevent userspace from changing doorbell affinity
  KVM: arm/arm64: GICv4: Prevent a VM using GICv4 from being saved
  KVM: arm/arm64: GICv4: Enable virtual cpuif if VLPIs can be delivered
  KVM: arm/arm64: GICv4: Hook vPE scheduling into vgic flush/sync
  KVM: arm/arm64: GICv4: Use the doorbell interrupt as an unblocking source
  KVM: arm/arm64: GICv4: Add doorbell interrupt handling
  KVM: arm/arm64: GICv4: Use pending_last as a scheduling hint
  KVM: arm/arm64: GICv4: Handle INVALL applied to a vPE
  KVM: arm/arm64: GICv4: Propagate property updates to VLPIs
  KVM: arm/arm64: GICv4: Handle MOVALL applied to a vPE
  KVM: arm/arm64: GICv4: Handle CLEAR applied to a VLPI
  KVM: arm/arm64: GICv4: Propagate affinity changes to the physical ITS
  KVM: arm/arm64: GICv4: Unmap VLPI when freeing an LPI
  ...

Pull powerpc fixes from Michael Ellerman:
 "A small batch of fixes, about 50% tagged for stable and the rest for
  recently merged code.

  There's one more fix for the >128T handling on hash. Once a process
  had requested a single mmap above 128T we would then always search
  above 128T. The correct behaviour is to consider the hint address in
  isolation for each mmap request.

  Then a couple of fixes for the IMC PMU, a missing EXPORT_SYMBOL in
  VAS, a fix for STRICT_KERNEL_RWX on 32-bit, and a fix to correctly
  identify P9 DD2.1 but in code that is currently not used by default.

  Thanks to: Aneesh Kumar K.V, Christophe Leroy, Madhavan Srinivasan,
  Sukadev Bhattiprolu"

* tag 'powerpc-4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64s: Fix Power9 DD2.1 logic in DT CPU features
  powerpc/perf: Fix IMC_MAX_PMU macro
  powerpc/perf: Fix pmu_count to count only nest imc pmus
  powerpc: Fix boot on BOOK3S_32 with CONFIG_STRICT_KERNEL_RWX
  powerpc/perf/imc: Use cpu_to_node() not topology_physical_package_id()
  powerpc/vas: Export chip_to_vas_id()
  powerpc/64s/slice: Use addr limit when computing slice mask

Pull SCSI target updates from Nicholas Bellinger:

 "This series is predominantly bug-fixes, with a few small improvements
  that have been outstanding over the last release cycle.

  As usual, the associated bug-fixes have CC' tags for stable.

  Also, things have been particularly quiet wrt new developments the
  last months, with most folks continuing to focus on stability atop 4.x
  stable kernels for their respective production configurations.

  Also at this point, the stable trees have been synced up with
  mainline. This will continue to be a priority, as production users
  tend to run exclusively atop stable kernels, a few releases behind
  mainline.

  The highlights include:

   - Fix PR PREEMPT_AND_ABORT null pointer dereference regression in
     v4.11+ (tangwenji)

   - Fix OOPs during removing TCMU device (Xiubo Li + Zhang Zhuoyu)

   - Add netlink command reply supported option for each device (Kenjiro
     Nakayama)

   - cxgbit: Abort the TCP connection in case of data out timeout (Varun
     Prakash)

   - Fix PR/ALUA file path truncation (David Disseldorp)

   - Fix double se_cmd completion during ->cmd_time_out (Mike Christie)

   - Fix QUEUE_FULL + SCSI task attribute handling in 4.1+ (Bryant Ly +
     nab)

   - Fix quiese during transport_write_pending_qf endless loop (nab)

   - Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK in 3.14+
     (Don White + nab)"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (35 commits)
  tcmu: Add a missing unlock on an error path
  tcmu: Fix some memory corruption
  iscsi-target: Fix non-immediate TMR reference leak
  iscsi-target: Make TASK_REASSIGN use proper se_cmd->cmd_kref
  target: Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK
  target: Fix quiese during transport_write_pending_qf endless loop
  target: Fix caw_sem leak in transport_generic_request_failure
  target: Fix QUEUE_FULL + SCSI task attribute handling
  iSCSI-target: Use common error handling code in iscsi_decode_text_input()
  target/iscsi: Detect conn_cmd_list corruption early
  target/iscsi: Fix a race condition in iscsit_add_reject_from_cmd()
  target/iscsi: Modify iscsit_do_crypto_hash_buf() prototype
  target/iscsi: Fix endianness in an error message
  target/iscsi: Use min() in iscsit_dump_data_payload() instead of open-coding it
  target/iscsi: Define OFFLOAD_BUF_SIZE once
  target: Inline transport_put_cmd()
  target: Suppress gcc 7 fallthrough warnings
  target: Move a declaration of a global variable into a header file
  tcmu: fix double se_cmd completion
  target: return SAM_STAT_TASK_SET_FULL for TCM_OUT_OF_RESOURCES
  ...

This fixes a missed function prototype callback from the timer conversions.
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20171123221902.GA75727@beast

The assignment of dvnode to itself is redundant and can be removed.
Cleans up warning detected by cppcheck:

fs/afs/dir.c:975: (warning) Redundant assignment of 'dvnode' to itself.

Fixes: d2ddc776 ("afs: Overhaul volume and server record caching and fileserver rotation")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Due to recent changes this piece of code is no longer needed.

Addresses-Coverity-ID: 1462033
Link: https://lkml.kernel.org/r/4923.1510957307@warthog.procyon.org.ukSigned-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

afs_mkdir(), afs_create(), afs_link() and afs_symlink() all need to drop
the target dentry if a signal causes the operation to be killed immediately
before we try to contact the server.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix some of dentry handling in AFS directory ops:

 (1) Do d_drop() on the new_dentry before assigning a new inode to it in
     afs_vnode_new_inode().  It's fine to do this before calling afs_iget()
     because the operation has taken place on the server.

 (2) Replace d_instantiate()/d_rehash() with d_add().

 (3) Don't d_drop() the new_dentry in afs_rename() on error.

Also fix afs_link() and afs_rename() to call key_put() on all error paths
where the key is taken.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Make afs_write_begin() wait for a page that's marked PG_writeback because:

 (1) We need to avoid interference with the data being stored so that the
     data on the server ends up in a defined state.

 (2) page->private is used to track the window of dirty data within a page,
     but it's also used by the storage code to track what's being written,
     being cleared by the completion notification.  Ownership can't be
     relinquished by the storage code until completion because it a store
     fails, the data must be remarked dirty.

Tracing shows something like the following (edited):

 x86_64-linux-gn-15940 [1] afs_page_dirty: vn=ffff8800bef33800 9c75 begin 0-125
    kworker/u8:3-114   [2] afs_page_dirty: vn=ffff8800bef33800 9c75 store+ 0-125
 x86_64-linux-gn-15940 [1] afs_page_dirty: vn=ffff8800bef33800 9c75 begin 0-2052
    kworker/u8:3-114   [2] afs_page_dirty: vn=ffff8800bef33800 9c75 clear 0-2052
    kworker/u8:3-114   [2] afs_page_dirty: vn=ffff8800bef33800 9c75 store 0-0
    kworker/u8:3-114   [2] afs_page_dirty: vn=ffff8800bef33800 9c75 WARN 0-0

The clear (completion) corresponding to the store+ (store continuation from
a previous page) happens between the second begin (afs_write_begin) and the
store corresponding to that.  This results in the second store not seeing
any data to write back, leading to the following warning:

WARNING: CPU: 2 PID: 114 at ../fs/afs/write.c:403 afs_write_back_from_locked_page+0x19d/0x76c [kafs]
Modules linked in: kafs(E)
CPU: 2 PID: 114 Comm: kworker/u8:3 Tainted: G            E   4.14.0-fscache+ #242
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
Workqueue: writeback wb_workfn (flush-afs-2)
task: ffff8800cad72600 task.stack: ffff8800cad44000
RIP: 0010:afs_write_back_from_locked_page+0x19d/0x76c [kafs]
RSP: 0018:ffff8800cad47aa0 EFLAGS: 00010246
RAX: 0000000000000001 RBX: ffff8800bef33a20 RCX: 0000000000000000
RDX: 000000000000000f RSI: ffffffff81c5d0e0 RDI: ffff8800cad72e78
RBP: ffff8800d31ea1e8 R08: ffff8800c1358000 R09: ffff8800ca00e400
R10: ffff8800cad47a38 R11: ffff8800c5d9e400 R12: 0000000000000000
R13: ffffea0002d9df00 R14: ffffffffa0023c1c R15: 0000000000007fdf
FS:  0000000000000000(0000) GS:ffff8800ca700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f85ac6c4000 CR3: 0000000001c10001 CR4: 00000000001606e0
Call Trace:
 ? clear_page_dirty_for_io+0x23a/0x267
 afs_writepages_region+0x1be/0x286 [kafs]
 afs_writepages+0x60/0x127 [kafs]
 do_writepages+0x36/0x70
 __writeback_single_inode+0x12f/0x635
 writeback_sb_inodes+0x2cc/0x452
 __writeback_inodes_wb+0x68/0x9f
 wb_writeback+0x208/0x470
 ? wb_workfn+0x22b/0x565
 wb_workfn+0x22b/0x565
 ? worker_thread+0x230/0x2ac
 process_one_work+0x2cc/0x517
 ? worker_thread+0x230/0x2ac
 worker_thread+0x1d4/0x2ac
 ? rescuer_thread+0x29b/0x29b
 kthread+0x15d/0x165
 ? kthread_create_on_node+0x3f/0x3f
 ? call_usermodehelper_exec_async+0x118/0x11f
 ret_from_fork+0x24/0x30
Signed-off-by: NDavid Howells <dhowells@redhat.com>