When reset is simulated MMU need to be brought into its initial state,
because that's what bootloaders/OS kernels assume. This is especially
important for MMUv3 because TLB state when the kernel is running is
significatly different from its reset state.

With this change it is possible to boot linux and get back to U-Boot
repeatedly.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

icountlevel SR value specifies lowest intlevel that does not do
instruction counting, so to disable instruction counting completely it
must be set to 0, not to 15.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

platform_restart implementatations do the same thing to reset CPU.
Don't duplicate that code, move it to a function and call it from
platform_restart.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Added defconfig, device tree and Xtensa variant header files for the
Cadence Configurable System Platform "xt_lnx" processor configuration.
Signed-off-by: Scott Telford <stelford@cadence.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Make default kernel load address 0xd0003000 for MMUv2 cores and
0x60003000 for noMMU cores. Don't initialize MMU inside vmlinux for
predefined MMUv2 cores (it's noop anyway).

This fixes the following defconfig build error:
  arch/xtensa/kernel/built-in.o: In function `fast_alloca':
  (.text+0x99a): dangerous relocation: j: cannot encode: _WindowUnderflow12
  arch/xtensa/kernel/built-in.o: In function `fast_alloca':
  (.text+0x99d): dangerous relocation: j: cannot encode: _WindowUnderflow8
  arch/xtensa/kernel/built-in.o: In function `fast_alloca':
  (.text+0x9a0): dangerous relocation: j: cannot encode: _WindowUnderflow4
  arch/xtensa/kernel/built-in.o: In function `window_overflow_restore_a0_fixup':
  (.text+0x23a3): dangerous relocation: j: cannot encode: (.DoubleExceptionVector.text+0x104)
  arch/xtensa/kernel/built-in.o: In function `window_overflow_restore_a0_fixup':
  (.text+0x23c1): dangerous relocation: j: cannot encode: (.DoubleExceptionVector.text+0x104)
  arch/xtensa/kernel/built-in.o: In function `window_overflow_restore_a0_fixup':
  (.text+0x23dd): dangerous relocation: j: cannot encode: (.DoubleExceptionVector.text+0x104)

With this change all xtensa defconfigs build correctly.
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Xtensa improvements for 4.8:

- add new kernel memory layouts for MMUv3 cores: with 256MB and 512MB
  KSEG size, starting at physical address other than 0;
- make kernel load address configurable;
- clean up kernel memory layout macros;
- drop sysmem early allocator and switch to memblock;
- enable kmemleak and memory reservation from the device tree;
- wire up new syscalls: userfaultfd, membarrier, mlock2, copy_file_range,
  preadv2 and pwritev2.

Wire up userfaultfd, membarrier, mlock2, copy_file_range, preadv2, pwritev2
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

This allows reserving regions of physical memory from the device tree.
See Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
for more details.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Memblock is the standard kernel boot-time memory tracker/allocator. Use
it instead of the custom sysmem allocator. This allows using kmemleak,
CMA and device tree memory reservation.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Now that the kernel load address and KSEG physical base address have
their own Kconfig symbols PLATFORM_DEFAULT_MEM seems redundant. It makes
little sense to use it in MMU configurations instead of KSEG_PADDR.
In noMMU configurations there's no explicit KSEG, so it's still useful
for the early cache initialization and definition of ARCH_PFN_OFFSET,
which affects mem_map size.

- limit it to noMMU; MMU variants have XCHAL_KSEG_PADDR and
  XCHAL_KSEG_SIZE;
- don't use it to define TASK_SIZE or MAX_LOW_PFN: first doesn't make
  any difference in noMMU, second is meaningless as there's no high
  memory;
- don't add default physical memory region: memory layout should come
  from the DT, bootloader tags, or memmap= command line parameter.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Make kernel load address explicit, independent of the selected MMU
configuration and configurable from Kconfig. Do not restrict it to the
first 512MB of the physical address space.

Cleanup kernel memory layout macros:

- rename VECBASE_RESET_VADDR to VECBASE_VADDR, XC_VADDR to VECTOR_VADDR;
- drop VIRTUAL_MEMORY_ADDRESS and LOAD_MEMORY_ADDRESS;
- introduce PHYS_OFFSET and use it in __va and __pa definitions;
- synchronize MMU/noMMU vectors, drop unused NMI vector;
- replace hardcoded vectors offset of 0x3000 with Kconfig symbol.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

MMUv3 is able to support low memory bigger than 128MB.
Implement 256MB and 512MB KSEG layouts:

- add Kconfig selector for KSEG layout;
- add KSEG base address, size and alignment definitions to
  arch/xtensa/include/asm/kmem_layout.h;
- use new definitions in TLB initialization;
- add build time memory map consistency checks.

See Documentation/xtensa/mmu.txt for the details of new memory layouts.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Create a header dedicated to memory layout definitions. Include it from
places where these definitions are needed.
Express vmalloc area address, VIRTUAL_MEMORY_ADDRESS and KERNELOFFSET
through KSEG address.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Make __ffs result type unsigned long to match generic asm
implementation. This fixes the following build warning:

  mm/nobootmem.c: In function '__free_pages_memory':
  include/linux/kernel.h:742:17: warning: comparison of distinct pointer
                                          types lacks a cast
    (void) (&_min1 == &_min2);  \
  		 ^
  mm/nobootmem.c:100:11: note: in expansion of macro 'min'
     order = min(MAX_ORDER - 1UL, __ffs(start));
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Pull ceph fix from Ilya Dryomov:
 "A fix for a long-standing bug in the incremental osdmap handling code
  that caused misdirected requests, tagged for stable"

  The tag is signed with a brand new key - Sage is on vacation and I
  didn't anticipate this"

* tag 'ceph-for-4.7-rc8' of git://github.com/ceph/ceph-client:
  libceph: apply new_state before new_up_client on incrementals

Pull networking fixes from David Miller:

 1) Fix memory leak in nftables, from Liping Zhang.

 2) Need to check result of vlan_insert_tag() in batman-adv otherwise we
    risk NULL skb derefs, from Sven Eckelmann.

 3) Check for dev_alloc_skb() failures in cfg80211, from Gregory
    Greenman.

 4) Handle properly when we have ppp_unregister_channel() happening in
    parallel with ppp_connect_channel(), from WANG Cong.

 5) Fix DCCP deadlock, from Eric Dumazet.

 6) Bail out properly in UDP if sk_filter() truncates the packet to be
    smaller than even the space that the protocol headers need.  From
    Michal Kubecek.

 7) Similarly for rose, dccp, and sctp, from Willem de Bruijn.

 8) Make TCP challenge ACKs less predictable, from Eric Dumazet.

 9) Fix infinite loop in bgmac_dma_tx_add() from Florian Fainelli.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (65 commits)
  packet: propagate sock_cmsg_send() error
  net/mlx5e: Fix del vxlan port command buffer memset
  packet: fix second argument of sock_tx_timestamp()
  net: switchdev: change ageing_time type to clock_t
  Update maintainer for EHEA driver.
  net/mlx4_en: Add resilience in low memory systems
  net/mlx4_en: Move filters cleanup to a proper location
  sctp: load transport header after sk_filter
  net/sched/sch_htb: clamp xstats tokens to fit into 32-bit int
  net: cavium: liquidio: Avoid dma_unmap_single on uninitialized ndata
  net: nb8800: Fix SKB leak in nb8800_receive()
  et131x: Fix logical vs bitwise check in et131x_tx_timeout()
  vlan: use a valid default mtu value for vlan over macsec
  net: bgmac: Fix infinite loop in bgmac_dma_tx_add()
  mlxsw: spectrum: Prevent invalid ingress buffer mapping
  mlxsw: spectrum: Prevent overwrite of DCB capability fields
  mlxsw: spectrum: Don't emit errors when PFC is disabled
  mlxsw: spectrum: Indicate support for autonegotiation
  mlxsw: spectrum: Force link training according to admin state
  r8152: add MODULE_VERSION
  ...

Pull overlayfs fixes from Miklos Szeredi:
 "This contains a fix for a potential crash/corruption issue and another
  where the suid/sgid bits weren't cleared on write"

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: verify upper dentry in ovl_remove_and_whiteout()
  ovl: Copy up underlying inode's ->i_mode to overlay inode
  ovl: handle ATTR_KILL*

Merge misc fixes from Andrew Morton:
 "Five fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  pps: do not crash when failed to register
  tools/vm/slabinfo: fix an unintentional printf
  testing/radix-tree: fix a macro expansion bug
  radix-tree: fix radix_tree_iter_retry() for tagged iterators.
  mm: memcontrol: fix cgroup creation failure after many small jobs

Pull intel kabylake drm fixes from Dave Airlie:
 "As mentioned Intel has gathered all the Kabylake fixes from -next,
  which we've enabled in 4.7 for the first time, these are pretty much
  limited in scope to only affects kabylake, which is hw that isn't
  shipping yet.  So I'm mostly okay with it going in now.

  If we don't land this, it might be a good idea to disable kabylake
  support in 4.7 before we ship"

* tag 'drm-fixes-for-v4.7-rc8-intel-kbl' of git://people.freedesktop.org/~airlied/linux: (28 commits)
  drm/i915/kbl: Introduce the first official DMC for Kabylake.
  drm/i915: Introduce Kabypoint PCH for Kabylake H/DT.
  drm/i915/gen9: implement WaConextSwitchWithConcurrentTLBInvalidate
  drm/i915/gen9: Add WaFbcHighMemBwCorruptionAvoidance
  drm/i195/fbc: Add WaFbcNukeOnHostModify
  drm/i915/gen9: Add WaFbcWakeMemOn
  drm/i915/gen9: Add WaFbcTurnOffFbcWatermark
  drm/i915/kbl: Add WaClearSlmSpaceAtContextSwitch
  drm/i915/gen9: Add WaEnableChickenDCPR
  drm/i915/kbl: Add WaDisableSbeCacheDispatchPortSharing
  drm/i915/kbl: Add WaDisableGafsUnitClkGating
  drm/i915/kbl: Add WaForGAMHang
  drm/i915: Add WaInsertDummyPushConstP for bxt and kbl
  drm/i915/kbl: Add WaDisableDynamicCreditSharing
  drm/i915/kbl: Add WaDisableGamClockGating
  drm/i915/gen9: Enable must set chicken bits in config0 reg
  drm/i915/kbl: Add WaDisableLSQCROPERFforOCL
  drm/i915/kbl: Add WaDisableSDEUnitClockGating
  drm/i915/kbl: Add WaDisableFenceDestinationToSLM for A0
  drm/i915/kbl: Add WaEnableGapsTsvCreditFix
  ...

Pull drm fixes from Dave Airlie:
 "Two i915 regression fixes.

  Intel have submitted some Kabylake fixes I'll send separately, since
  this is the first kernel with kabylake support and they don't go much
  outside that area I think they should be fine"

* tag 'drm-fixes-for-v4.7-rc8-intel' of git://people.freedesktop.org/~airlied/linux:
  drm/i915: add missing condition for committing planes on crtc
  drm/i915: Treat eDP as always connected, again

Pull m68k upddates from Geert Uytterhoeven:
 - assorted spelling fixes
 - defconfig updates

* tag 'm68k-for-v4.8-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
  m68k/defconfig: Update defconfigs for v4.7-rc2
  m68k: Assorted spelling fixes

Pull ARM SoC fixes from Olof Johansson:
 "A handful of fixes before final release:

  Marvell Armada:
   - One to fix a typo in the devicetree specifying memory ranges for
     the crypto engine
   - Two to deal with marking PCI and device-memory as strongly ordered
     to avoid hardware deadlocks, in particular when enabling above
     crypto driver.
   - Compile fix for PM

  Allwinner:
   - DT clock fixes to deal with u-boot-enabled framebuffer (simplefb).
   - Make R8 (C.H.I.P. SoC) inherit system compatibility from A13 to
     make clocks register proper.

  Tegra:
   - Fix SD card voltage setting on the Tegra3 Beaver dev board

  Misc:
   - Two maintainers updates for STM32 and STi platforms"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  ARM: tegra: beaver: Allow SD card voltage to be changed
  MAINTAINERS: update STi maintainer list
  MAINTAINERS: update STM32 maintainers list
  ARM: mvebu: compile pm code conditionally
  ARM: dts: sun7i: Fix pll3x2 and pll7x2 not having a parent clock
  ARM: dts: sunxi: Add pll3 to simplefb nodes clocks lists
  ARM: dts: armada-38x: fix MBUS_ID for crypto SRAM on Armada 385 Linksys
  ARM: mvebu: map PCI I/O regions strongly ordered
  ARM: mvebu: fix HW I/O coherency related deadlocks
  ARM: sunxi/dt: make the CHIP inherit from allwinner,sun5i-a13

Pull crypto fixes from Herbert Xu:
 "This fixes a sporadic build failure in the qat driver as well as a
  memory corruption bug in rsa-pkcs1pad"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: rsa-pkcs1pad - fix rsa-pkcs1pad request struct
  crypto: qat - make qat_asym_algs.o depend on asn1 headers

Pull key handling fixes from James Morris:
 "Quoting David Howells:

  Here are three miscellaneous fixes:

  (1) Fix a panic in some debugging code in PKCS#7.  This can only
      happen by explicitly inserting a #define DEBUG into the code.

  (2) Fix the calculation of the digest length in the PE file parser.
      This causes a failure where there should be a success.

  (3) Fix the case where an X.509 cert can be added as an asymmetric key
      to a trusted keyring with no trust restriction if no AKID is
      supplied.

  Bugs (1) and (2) aren't particularly problematic, but (3) allows a
  security check to be bypassed.  Happily, this is a recent regression
  and never made it into a released kernel"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  KEYS: Fix for erroneous trust of incorrectly signed X.509 certs
  pefile: Fix the failure of calculation for digest
  PKCS#7: Fix panic when referring to the empty AKID when DEBUG defined

Pull input fixes from Dmitry Torokhov:
 "A few more fixes for the input subsystem:

   - restore naming for tsc2005 touchscreens as some userspace match on it
   - fix out of bound access in legacy keyboard driver
   - fixup in RMI4 driver

  Everything is tagged for stable as well"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: tsc200x - report proper input_dev name
  tty/vt/keyboard: fix OOB access in do_compute_shiftstate()
  Input: synaptics-rmi4 - fix maximum size check for F12 control register 8

Pull libnvdimm fix from Dan Williams:
 "This contains a regression fix for a problem that was introduced in
  v4.7-rc6.

  In 4.7-rc1 we introduced auto-probing for the ACPI DSM (device-
  specific-method) format that the platform firmware implements for
  nvdimm devices.  We initially fixed a regression in probing the QEMU
  DSM implementation by making acpi_check_dsm() tolerant of the way QEMU
  reports the "0 DSMs supported" condition.

  However, that broke HPE platforms since that tolerance caused the
  driver to mistakenly match the 1-zero-byte response those platforms
  give to "unknown" commands.  Instead, we simply make the driver
  tolerant of not finding any supported DSMs.  This has been tested to
  work with both QEMU and HPE platforms.

  This commit has appeared in a -next release with no reported issues"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  nfit: make DIMM DSMs optional

Pull GPIO fix from Linus Walleij:
 "Compile problem fix for Tegra,

  Sorry to send this in the last minute but Ingo says this build failure
  is very prominent so I'm not going to wait for v4.7 before sending it.

  It is a case of COMPILE_TEST causing more problems than it solves and
  I'm already swearing about me shooting myself in the foot with that
  gun :("

* tag 'gpio-v4.7-6' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpio: tegra: don't auto-enable for COMPILE_TEST

Pull clk fixes from Michael Turquette:
 "Fix a bug in the at91 clk driver, two compile time warnings in sunxi
  clk drivers, and one bug in a sunxi clk driver introduced in the 4.7
  merge window"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: at91: fix clk_programmable_set_parent()
  clk: sunxi: remove unused variable
  clk: sunxi: display: Add per-clock flags
  clk: sunxi: tcon-ch1: Do not return a negative error in get_parent

Pull libata fix from Tejun Heo:
 "Another fallout from max_sectors bump a couple years ago.  The lite-on
  optical drive times out on large requests"

* 'for-4.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata:
  libata: LITE-ON CX1-JB256-HP needs lower max_sectors

Pull MMC fixes from Ulf Hansson:
 "Here are a few late mmc fixes intended for v4.7 final.

  MMC core:
   - Fix eMMC packed command header endianness
   - Fix free of uninitialized buffer for mmc ioctl

  MMC host:
   - pxamci: Fix potential oops in ->probe()"

* tag 'mmc-v4.7-rc7' of git://git.linaro.org/people/ulf.hansson/mmc:
  mmc: pxamci: fix potential oops
  mmc: block: fix packed command header endianness
  mmc: block: fix free of uninitialized 'idata->buf'

Pull sound fixes from Takashi Iwai:
 "No surprise, just a few small fixes: a couple of changes are seen in
  the core part, and both of them are rather for unusual error paths.

  The rest are the regular HD-audio fixes and one USB-audio regression
  fix"

* tag 'sound-4.7-fix2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: usb-audio: Fix quirks code is not called
  ALSA: hda: add AMD Stoney PCI ID with proper driver caps
  ALSA: hda - fix use-after-free after module unload
  ALSA: pcm: Free chmap at PCM free callback, too
  ALSA: ctl: Stop notification after disconnection
  ALSA: hda/realtek - add new pin definition in alc225 pin quirk table

Pull NVMe fix from Jens Axboe:
 "Late addition here, it's basically a revert of a patch that was added
  in this merge window, but has proven to cause problems.

  This is swapping out the RCU based namespace protection with a good
  old mutex instead"

* 'for-linus' of git://git.kernel.dk/linux-block:
  nvme: Remove RCU namespace protection

With this command sequence:

  modprobe plip
  modprobe pps_parport
  rmmod pps_parport

the partport_pps modules causes this crash:

  BUG: unable to handle kernel NULL pointer dereference at (null)
  IP: parport_detach+0x1d/0x60 [pps_parport]
  Oops: 0000 [#1] SMP
  ...
  Call Trace:
    parport_unregister_driver+0x65/0xc0 [parport]
    SyS_delete_module+0x187/0x210

The sequence that builds up to this is:

 1) plip is loaded and takes the parport device for exclusive use:

    plip0: Parallel port at 0x378, using IRQ 7.

 2) pps_parport then fails to grab the device:

    pps_parport: parallel port PPS client
    parport0: cannot grant exclusive access for device pps_parport
    pps_parport: couldn't register with parport0

 3) rmmod of pps_parport is then killed because it tries to access
    pardev->name, but pardev (taken from port->cad) is NULL.

So add a check for NULL in the test there too.

Link: http://lkml.kernel.org/r/20160714115245.12651-1-jslaby@suse.czSigned-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The curly braces are missing here so we print stuff unintentionally.

Fixes: 9da4714a ('slub: slabinfo update for cmpxchg handling')
Link: http://lkml.kernel.org/r/20160715211243.GE19522@mwandaSigned-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There are no parentheses around this macro and it causes a problem when
we do:

	index = rand() % THRASH_SIZE;

Link: http://lkml.kernel.org/r/20160715210953.GC19522@mwandaSigned-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

radix_tree_iter_retry() resets slot to NULL, but it doesn't reset tags.
Then NULL slot and non-zero iter.tags passed to radix_tree_next_slot()
leading to crash:

  RIP: radix_tree_next_slot include/linux/radix-tree.h:473
    find_get_pages_tag+0x334/0x930 mm/filemap.c:1452
  ....
  Call Trace:
    pagevec_lookup_tag+0x3a/0x80 mm/swap.c:960
    mpage_prepare_extent_to_map+0x321/0xa90 fs/ext4/inode.c:2516
    ext4_writepages+0x10be/0x2b20 fs/ext4/inode.c:2736
    do_writepages+0x97/0x100 mm/page-writeback.c:2364
    __filemap_fdatawrite_range+0x248/0x2e0 mm/filemap.c:300
    filemap_write_and_wait_range+0x121/0x1b0 mm/filemap.c:490
    ext4_sync_file+0x34d/0xdb0 fs/ext4/fsync.c:115
    vfs_fsync_range+0x10a/0x250 fs/sync.c:195
    vfs_fsync fs/sync.c:209
    do_fsync+0x42/0x70 fs/sync.c:219
    SYSC_fdatasync fs/sync.c:232
    SyS_fdatasync+0x19/0x20 fs/sync.c:230
    entry_SYSCALL_64_fastpath+0x23/0xc1 arch/x86/entry/entry_64.S:207

We must reset iterator's tags to bail out from radix_tree_next_slot()
and go to the slow-path in radix_tree_next_chunk().

Fixes: 46437f9a ("radix-tree: fix race in gang lookup")
Link: http://lkml.kernel.org/r/1468495196-10604-1-git-send-email-aryabinin@virtuozzo.comSigned-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The memory controller has quite a bit of state that usually outlives the
cgroup and pins its CSS until said state disappears.  At the same time
it imposes a 16-bit limit on the CSS ID space to economically store IDs
in the wild.  Consequently, when we use cgroups to contain frequent but
small and short-lived jobs that leave behind some page cache, we quickly
run into the 64k limitations of outstanding CSSs.  Creating a new cgroup
fails with -ENOSPC while there are only a few, or even no user-visible
cgroups in existence.

Although pinning CSSs past cgroup removal is common, there are only two
instances that actually need an ID after a cgroup is deleted: cache
shadow entries and swapout records.

Cache shadow entries reference the ID weakly and can deal with the CSS
having disappeared when it's looked up later.  They pose no hurdle.

Swap-out records do need to pin the css to hierarchically attribute
swapins after the cgroup has been deleted; though the only pages that
remain swapped out after offlining are tmpfs/shmem pages.  And those
references are under the user's control, so they are manageable.

This patch introduces a private 16-bit memcg ID and switches swap and
cache shadow entries over to using that.  This ID can then be recycled
after offlining when the CSS remains pinned only by objects that don't
specifically need it.

This script demonstrates the problem by faulting one cache page in a new
cgroup and deleting it again:

  set -e
  mkdir -p pages
  for x in `seq 128000`; do
    [ $((x % 1000)) -eq 0 ] && echo $x
    mkdir /cgroup/foo
    echo $$ >/cgroup/foo/cgroup.procs
    echo trex >pages/$x
    echo $$ >/cgroup/cgroup.procs
    rmdir /cgroup/foo
  done

When run on an unpatched kernel, we eventually run out of possible IDs
even though there are no visible cgroups:

  [root@ham ~]# ./cssidstress.sh
  [...]
  65000
  mkdir: cannot create directory '/cgroup/foo': No space left on device

After this patch, the IDs get released upon cgroup destruction and the
cache and css objects get released once memory reclaim kicks in.

[hannes@cmpxchg.org: init the IDR]
  Link: http://lkml.kernel.org/r/20160621154601.GA22431@cmpxchg.org
Fixes: b2052564 ("mm: memcontrol: continue cache reclaim from offlined groups")
Link: http://lkml.kernel.org/r/20160617162516.GD19084@cmpxchg.orgSigned-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: John Garcia <john.garcia@mesosphere.io>
Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Nikolay Borisov <kernel@kyup.com>
Cc: <stable@vger.kernel.org>	[3.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

I stumbled over a build error with COMPILE_TEST and CONFIG_OF
disabled:

drivers/gpio/gpio-tegra.c: In function 'tegra_gpio_probe':
drivers/gpio/gpio-tegra.c:603:9: error: 'struct gpio_chip' has no member named 'of_node'

The problem is that the newly added GPIO_TEGRA Kconfig symbol
does not have a dependency on CONFIG_OF. However, there is another
problem here as the driver gets enabled unconditionally whenever
COMPILE_TEST is set.

This fixes both problems, by making the symbol user-visible
when COMPILE_TEST is set and default-enabled for ARCH_TEGRA=y.

As a side-effect, it is now possible to compile-test a Tegra
kernel with GPIO support disabled, which is harmless.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 4dd4dd1d ("gpio: tegra: Allow compile test")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Currently, osd_weight and osd_state fields are updated in the encoding
order.  This is wrong, because an incremental map may look like e.g.

    new_up_client: { osd=6, addr=... } # set osd_state and addr
    new_state: { osd=6, xorstate=EXISTS } # clear osd_state

Suppose osd6's current osd_state is EXISTS (i.e. osd6 is down).  After
applying new_up_client, osd_state is changed to EXISTS | UP.  Carrying
on with the new_state update, we flip EXISTS and leave osd6 in a weird
"!EXISTS but UP" state.  A non-existent OSD is considered down by the
mapping code

2087    for (i = 0; i < pg->pg_temp.len; i++) {
2088            if (ceph_osd_is_down(osdmap, pg->pg_temp.osds[i])) {
2089                    if (ceph_can_shift_osds(pi))
2090                            continue;
2091
2092                    temp->osds[temp->size++] = CRUSH_ITEM_NONE;

and so requests get directed to the second OSD in the set instead of
the first, resulting in OSD-side errors like:

[WRN] : client.4239 192.168.122.21:0/2444980242 misdirected client.4239.1:2827 pg 2.5df899f2 to osd.4 not [1,4,6] in e680/680

and hung rbds on the client:

[  493.566367] rbd: rbd0: write 400000 at 11cc00000 (0)
[  493.566805] rbd: rbd0:   result -6 xferred 400000
[  493.567011] blk_update_request: I/O error, dev rbd0, sector 9330688

The fix is to decouple application from the decoding and:
- apply new_weight first
- apply new_state before new_up_client
- twiddle osd_state flags if marking in
- clear out some of the state if osd is destroyed

Fixes: http://tracker.ceph.com/issues/14901

Cc: stable@vger.kernel.org # 3.15+: 6dd74e44: libceph: set 'exists' flag for newly up osd
Cc: stable@vger.kernel.org # 3.15+
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Josh Durgin <jdurgin@redhat.com>