This constifies a few buffers used in the backref code.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Tracepoint arguments are all read-only.  If we mark the arguments
as const, we're able to keep or convert those arguments to const
where appropriate.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

We have reader helpers for most of the on-disk structures that use
an extent_buffer and pointer as offset into the buffer that are
read-only.  We should mark them as const and, in turn, allow consumers
of these interfaces to mark the buffers const as well.

No impact on code, but serves as documentation that a buffer is intended
not to be modified.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

The sectorsize member of btrfs_block_group_cache is unused. So remove it, this
reduces the number of holes in the struct.

With patch:
/* size: 856, cachelines: 14, members: 40 */
/* sum members: 837, holes: 4, sum holes: 19 */
/* bit holes: 1, sum bit holes: 29 bits */
/* last cacheline: 24 bytes */

Without patch:
/* size: 864, cachelines: 14, members: 41 */
/* sum members: 841, holes: 5, sum holes: 23 */
/* bit holes: 1, sum bit holes: 29 bits */
/* last cacheline: 32 bytes */
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

__btrfs_alloc_chunk contains code which boils down to:

    ndevs = min(ndevs, devs_max)

It's conditional upon devs_max not being 0. However, it cannot really be 0
since it's always set to either BTRFS_MAX_DEVS_SYS_CHUNK or
BTRFS_MAX_DEVS(fs_info->chunk_root). So eliminate the condition check and use
min explicitly. This has no functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

No functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

No functional changes, just make the loop a bit more readable
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Pull MIPS fixes from Ralf Baechle:
 "Another round of MIPS fixes:

   - compressed boot: Ignore a generated .c file

   - VDSO: Fix a register clobber list

   - DECstation: Fix an int-handler.S CPU_DADDI_WORKAROUNDS regression

   - Octeon: Fix recent cleanups that cleaned away a bit too much thus
     breaking the arch side of the EDAC and USB drivers.

   - uasm: Fix duplicate const in "const struct foo const bar[]" which
     GCC 7.1 no longer accepts.

   - Fix race on setting and getting cpu_online_mask

   - Fix preemption issue. To do so cleanly introduce macro to get the
     size of L3 cache line.

   - Revert include cleanup that sometimes results in build error

   - MicroMIPS uses bit 0 of the PC to indicate microMIPS mode. Make
     sure this bit is set for kernel entry as well.

   - Prevent configuring the kernel for both microMIPS and MT. There are
     no such CPUs currently and thus the combination is unsupported and
     results in build errors.

  This has been sitting in linux-next for a few days and has survived
  automated testing by Imagination's test farm. No known regressions
  pending except a number of issues that crept up due to lots of people
  switching to GCC 7.1"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: Set ISA bit in entry-y for microMIPS kernels
  MIPS: Prevent building MT support for microMIPS kernels
  MIPS: PCI: Fix smp_processor_id() in preemptible
  MIPS: Introduce cpu_tcache_line_size
  MIPS: DEC: Fix an int-handler.S CPU_DADDI_WORKAROUNDS regression
  MIPS: VDSO: Fix clobber lists in fallback code paths
  Revert "MIPS: Don't unnecessarily include kmalloc.h into <asm/cache.h>."
  MIPS: OCTEON: Fix USB platform code breakage.
  MIPS: Octeon: Fix broken EDAC driver.
  MIPS: gitignore: ignore generated .c files
  MIPS: Fix race on setting and getting cpu_online_mask
  MIPS: mm: remove duplicate "const" qualifier on insn_table

Merge tag 'driver-core-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core fixes from Greg KH:
 "Here are three firmware core fixes for 4.13-rc5.

  All three of these fix reported issues and have been floating around
  for a few weeks. They have been in linux-next with no reported
  problems"

* tag 'driver-core-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  firmware: avoid invalid fallback aborts by using killable wait
  firmware: fix batched requests - send wake up on failure on direct lookups
  firmware: fix batched requests - wake all waiters

Pull char/misc fixes from Greg KH:
 "Here are two patches for 4.13-rc5.

  One is a fix for a reported thunderbolt issue, and the other a fix for
  an MEI driver issue. Both have been in linux-next with no reported
  issues"

* tag 'char-misc-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  thunderbolt: Do not enumerate more ports from DROM than the controller has
  mei: exclude device from suspend direct complete optimization

Pull tty/serial fixes from Greg KH:
 "Here are two tty serial driver fixes for 4.13-rc5. One is a revert of
  a -rc1 patch that turned out to not be a good idea, and the other is a
  fix for the pl011 serial driver.

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

* tag 'tty-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  Revert "serial: Delete dead code for CIR serial ports"
  tty: pl011: fix initialization order of QDF2400 E44

Pull staging/iio fixes from Greg KH:
 "Here are some Staging and IIO driver fixes for 4.13-rc5.

  Nothing major, just a number of small fixes for reported issues. All
  of these have been in linux-next for a while now with no reported
  issues. Full details are in the shortlog"

* tag 'staging-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: comedi: comedi_fops: do not call blocking ops when !TASK_RUNNING
  iio: aspeed-adc: wait for initial sequence.
  iio: accel: bmc150: Always restore device to normal mode after suspend-resume
  staging:iio:resolver:ad2s1210 fix negative IIO_ANGL_VEL read
  iio: adc: axp288: Fix the GPADC pin reading often wrongly returning 0
  iio: adc: vf610_adc: Fix VALT selection value for REFSEL bits
  iio: accel: st_accel: add SPI-3wire support
  iio: adc: Revert "axp288: Drop bogus AXP288_ADC_TS_PIN_CTRL register modifications"
  iio: adc: sun4i-gpadc-iio: fix unbalanced irq enable/disable
  iio: pressure: st_pressure_core: disable multiread by default for LPS22HB
  iio: light: tsl2563: use correct event code

Pull USB fixes from Greg KH:
 "Here are a number of small USB driver fixes and new device ids for
  4.13-rc5. There is the usual gadget driver fixes, some new quirks for
  "messy" hardware, and some new device ids.

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

* tag 'usb-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: serial: pl2303: add new ATEN device id
  usb: quirks: Add no-lpm quirk for Moshi USB to Ethernet Adapter
  USB: Check for dropped connection before switching to full speed
  usb:xhci:Add quirk for Certain failing HP keyboard on reset after resume
  usb: renesas_usbhs: gadget: fix unused-but-set-variable warning
  usb: renesas_usbhs: Fix UGCTRL2 value for R-Car Gen3
  usb: phy: phy-msm-usb: Fix usage of devm_regulator_bulk_get()
  usb: gadget: udc: renesas_usb3: Fix usb_gadget_giveback_request() calling
  usb: dwc3: gadget: Correct ISOC DATA PIDs for short packets
  USB: serial: option: add D-Link DWM-222 device ID
  usb: musb: fix tx fifo flush handling again
  usb: core: unlink urbs from the tail of the endpoint's urb_list
  usb-storage: fix deadlock involving host lock and scsi_done
  uas: Add US_FL_IGNORE_RESIDUE for Initio Corporation INIC-3069
  USB: hcd: Mark secondary HCD as dead if the primary one died
  USB: serial: cp210x: add support for Qivicon USB ZigBee dongle

Pull another MTD fix from Brian Norris:
 "An mtdblock regression occurred in -rc1 (all writes were broken!), in
  the process of some block subsystem refactoring. Noticed and fixed
  last week, but I'm a little slow on the uptake"

* tag 'for-linus-20170812' of git://git.infradead.org/linux-mtd:
  mtd: blkdevs: Fix mtd block write failure

All the MTD block write requests are failing with
following error messages

    mkfs.ext4  /dev/mtdblock0

    print_req_error: I/O error, dev mtdblock0, sector 0
    Buffer I/O error on dev mtdblock0, logical block 0,
    lost async page write

The control is going to default case after block write request
because of missing return.

Fixes: commit 2a842aca ("block: introduce new block status code type")
Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Pull SCSI target fixes from Nicholas Bellinger:
 "The highlights include:

   - Fix iscsi-target payload memory leak during
     ISCSI_FLAG_TEXT_CONTINUE (Varun Prakash)

   - Fix tcm_qla2xxx incorrect use of tcm_qla2xxx_free_cmd during ABORT
     (Pascal de Bruijn + Himanshu Madhani + nab)

   - Fix iscsi-target long-standing issue with parallel delete of a
     single network portal across multiple target instances (Gary Guo +
     nab)

   - Fix target dynamic se_node GPF during uncached shutdown regression
     (Justin Maggard + nab)"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  target: Fix node_acl demo-mode + uncached dynamic shutdown regression
  iscsi-target: Fix iscsi_np reset hung task during parallel delete
  qla2xxx: Fix incorrect tcm_qla2xxx_free_cmd use during TMR ABORT (v2)
  cxgbit: fix sg_nents calculation
  iscsi-target: fix invalid flags in text response
  iscsi-target: fix memory leak in iscsit_setup_text_cmd()
  cxgbit: add missing __kfree_skb()
  tcmu: free old string on reconfig
  tcmu: Fix possible to/from address overflow when doing the memcpy

Pull xen fixes from Juergen Gross:
 "Some fixes for Xen:

   - a fix for a regression introduced in 4.13 for a Xen HVM-guest
     configured with KASLR

   - a fix for a possible deadlock in the xenbus driver when booting the
     system

   - a fix for lost interrupts in Xen guests"

* tag 'for-linus-4.13b-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/events: Fix interrupt lost during irq_disable and irq_enable
  xen: avoid deadlock in xenbus
  xen: fix hvm guest with kaslr enabled
  xen: split up xen_hvm_init_shared_info()
  x86: provide an init_mem_mapping hypervisor hook

Pull NFS client fixes from Anna Schumaker:
 "A few more NFS client bugfixes from me for rc5.

  Dros has a stable fix for flexfiles to prevent leaking the
  nfs4_ff_ds_version arrays when freeing a layout, Trond fixed a
  potential recovery loop situation with the TEST_STATEID operation, and
  Christoph fixed up the pNFS blocklayout Kconfig options to prevent
  unsafe use with kernels that don't have large block device support.
  Summary:

  Stable fix:
   - fix leaking nfs4_ff_ds_version array

  Other fixes:
   - improve TEST_STATEID OLD_STATEID handling to prevent recovery loop

   - require 64-bit sector_t for pNFS blocklayout to prevent 32-bit
     compile errors"

* tag 'nfs-for-4.13-5' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  pnfs/blocklayout: require 64-bit sector_t
  NFSv4: Ignore NFS4ERR_OLD_STATEID in nfs41_check_open_stateid()
  nfs/flexfiles: fix leak of nfs4_ff_ds_version arrays

Pull block fixes from Jens Axboe:
 "A set of fixes that should go into this series. This contains:

   - Fix from Bart for blk-mq requeue queue running, preventing a
     continued loop of run/restart.

   - Fix for a bio/blk-integrity issue, in two parts. One from
     Christoph, fixing where verification happens, and one from Milan,
     for a NULL profile.

   - NVMe pull request, most of the changes being for nvme-fc, but also
     a few trivial core/pci fixes"

* 'for-linus' of git://git.kernel.dk/linux-block:
  nvme: fix directive command numd calculation
  nvme: fix nvme reset command timeout handling
  nvme-pci: fix CMB sysfs file removal in reset path
  lpfc: support nvmet_fc defer_rcv callback
  nvmet_fc: add defer_req callback for deferment of cmd buffer return
  nvme: strip trailing 0-bytes in wwid_show
  block: Make blk_mq_delay_kick_requeue_list() rerun the queue at a quiet time
  bio-integrity: only verify integrity on the lowest stacked driver
  bio-integrity: Fix regression if profile verify_fn is NULL

Pull MMC fixes from Ulf Hansson:
 "MMC core:

   - fix lockdep splat when removing mmc_block module

   - fix the logic for setting eMMC HS400ES signal voltage

  MMC host:

   - omap_hsmmc: add CMD23 capability to fix -EIO errors"

* tag 'mmc-v4.13-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc:
  mmc: block: fix lockdep splat when removing mmc_block module
  mmc: mmc: correct the logic for setting HS400ES signal voltage
  mmc: host: omap_hsmmc: Add CMD23 capability to omap_hsmmc driver

Pull fbdev fixes from Bartlomiej Zolnierkiewicz:

 - allow user to disable write combined mapping in efifb driver (Dave
   Airlie)

 - fix use after free bugs on driver removal in imxfb driver (Dan
   Carpenter)

 - fix unused variable warning in omapfb driver (Arnd Bergmann)

* tag 'fbdev-v4.13-rc5' of git://github.com/bzolnier/linux:
  efifb: allow user to disable write combined mapping.
  fbdev: omapfb: remove unused variable
  video: fbdev: imxfb: use after free in imxfb_remove()

Pull fuse fixes from Miklos Szeredi:
 "Fix a few bugs in fuse"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: set mapping error in writepage_locked when it fails
  fuse: Dont call set_page_dirty_lock() for ITER_BVEC pages for async_dio
  fuse: initialize the flock flag in fuse_file on allocation

Pull IOMMU fix from Joerg Roedel:
 "Fix a NULL-pointer dereference in arm_smmu_add_device"

* tag 'iommu-fixes-v4.13-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/arm-smmu: fix null-pointer dereference in arm_smmu_add_device

The blocklayout code does not compile cleanly for a 32-bit sector_t,
and also has no reliable checks for devices sizes, which makes it
unsafe to use with a kernel that doesn't support large block devices.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 5c83746a ("pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing")
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Pull powerpc fixes from Michael Ellerman:
 "All fixes for code that went in this cycle.

   - a revert of an optimisation to the syscall exit path, which could
     lead to an oops on either older machines or machines with > 1TB of
     memory

   - disable some deep idle states if the firmware configuration for
     them fails

   - re-enable HARD/SOFT lockup detectors in defconfigs after a Kconfig
     change

   - six fairly small patches fixing bugs in our new watchdog code

  Thanks to: Gautham R Shenoy, Nicholas Piggin"

* tag 'powerpc-4.13-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/watchdog: add locking around init/exit functions
  powerpc/watchdog: Fix marking of stuck CPUs
  powerpc/watchdog: Fix final-check recovered case
  powerpc/watchdog: Moderate touch_nmi_watchdog overhead
  powerpc/watchdog: Improve watchdog lock primitive
  powerpc: NMI IPI improve lock primitive
  powerpc/configs: Re-enable HARD/SOFT lockup detectors
  powerpc/powernv/idle: Disable LOSE_FULL_CONTEXT states when stop-api fails
  Revert "powerpc/64: Avoid restore_math call if possible in syscall exit"

Commit c54451a5 "iommu/arm-smmu: Fix the error path in arm_smmu_add_device"
removed fwspec assignment in legacy_binding path as redundant which is
wrong. It needs to be updated after fwspec initialisation in
arm_smmu_register_legacy_master() as it is dereferenced later. Without
this there is a NULL-pointer dereference panic during boot on some hosts.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Here is a device has xen-pirq-MSI interrupt. Dom0 might lost interrupt
during driver irq_disable/irq_enable. Here is the scenario,
 1. irq_disable -> disable_dynirq -> mask_evtchn(irq channel)
 2. dev interrupt raised by HW and Xen mark its evtchn as pending
 3. irq_enable -> startup_pirq -> eoi_pirq ->
    clear_evtchn(channel of irq) -> clear pending status
 4. consume_one_event process the irq event without pending bit assert
    which result in interrupt lost once
 5. No HW interrupt raising anymore.

Now use enable_dynirq for enable_pirq of xen_pirq_chip to remove
eoi_pirq when irq_enable.
Signed-off-by: Liu Shuo <shuo.a.liu@intel.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

When starting the xenwatch thread a theoretical deadlock situation is
possible:

xs_init() contains:

    task = kthread_run(xenwatch_thread, NULL, "xenwatch");
    if (IS_ERR(task))
        return PTR_ERR(task);
    xenwatch_pid = task->pid;

And xenwatch_thread() does:

    mutex_lock(&xenwatch_mutex);
    ...
    event->handle->callback();
    ...
    mutex_unlock(&xenwatch_mutex);

The callback could call unregister_xenbus_watch() which does:

    ...
    if (current->pid != xenwatch_pid)
        mutex_lock(&xenwatch_mutex);
    ...

In case a watch is firing before xenwatch_pid could be set and the
callback of that watch unregisters a watch, then a self-deadlock would
occur.

Avoid this by setting xenwatch_pid in xenwatch_thread().
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

Pull NVMe fixes from Christoph:

"A few more small fixes - the fc/lpfc update is the biggest by far."

A Xen HVM guest running with KASLR enabled will die rather soon today
because the shared info page mapping is using va() too early. This was
introduced by commit a5d5f328 ("xen:
allocate page for shared info page from low memory").

In order to fix this use early_memremap() to get a temporary virtual
address for shared info until va() can be used safely.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>

Instead of calling xen_hvm_init_shared_info() on boot and resume split
it up into a boot time function searching for the pfn to use and a
mapping function doing the hypervisor mapping call.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>

Provide a hook in hypervisor_x86 called after setting up initial
memory mapping.

This is needed e.g. by Xen HVM guests to map the hypervisor shared
info page.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>

This ensures that we see errors on fsync when writeback fails.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

Pull drm fixes from Dave Airlie:
 "Nothing too earth shattering here, it just seems like lots of little
  things all over the place.

  msm has probably the larger amount of changes, but they all seem fine,
  otherwise, some rockchip, i915, etnaviv and exynos fixes, along with
  one nouveau regression fix for some older GPUs"

* tag 'drm-fixes-for-v4.13-rc5' of git://people.freedesktop.org/~airlied/linux: (35 commits)
  drm/nouveau/disp/nv04: avoid creation of output paths
  drm: make DRM_STM default n
  drm/exynos: forbid creating framebuffers from too small GEM buffers
  drm/etnaviv: Fix off-by-one error in reloc checking
  drm/i915: fix backlight invert for non-zero minimum brightness
  drm/i915/shrinker: Wrap need_resched() inside preempt-disable
  drm/i915/perf: fix flex eu registers programming
  drm/i915: Fix out-of-bounds array access in bdw_load_gamma_lut
  drm/i915/gvt: Change the max length of mmio_reg_rw from 4 to 8
  drm/i915/gvt: Initialize MMIO Block with HW state
  drm/rockchip: vop: report error when check resource error
  drm/rockchip: vop: round_up pitches to word align
  drm/rockchip: vop: fix NV12 video display error
  drm/rockchip: vop: fix iommu page fault when resume
  drm/i915/gvt: clean workload queue if error happened
  drm/i915/gvt: change resetting to resetting_eng
  drm/msm: gpu: don't abuse dma_alloc for non-DMA allocations
  drm/msm: gpu: call qcom_mdt interfaces only for ARCH_QCOM
  drm/msm/adreno: Prevent unclocked access when retrieving timestamps
  drm/msm: Remove __user from __u64 data types
  ...

Merge misc fixes from Andrew Morton:
 "21 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (21 commits)
  userfaultfd: replace ENOSPC with ESRCH in case mm has gone during copy/zeropage
  zram: rework copy of compressor name in comp_algorithm_store()
  rmap: do not call mmu_notifier_invalidate_page() under ptl
  mm: fix list corruptions on shmem shrinklist
  mm/balloon_compaction.c: don't zero ballooned pages
  MAINTAINERS: copy virtio on balloon_compaction.c
  mm: fix KSM data corruption
  mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem
  mm: make tlb_flush_pending global
  mm: refactor TLB gathering API
  Revert "mm: numa: defer TLB flush for THP migration as long as possible"
  mm: migrate: fix barriers around tlb_flush_pending
  mm: migrate: prevent racy access to tlb_flush_pending
  fault-inject: fix wrong should_fail() decision in task context
  test_kmod: fix small memory leak on filesystem tests
  test_kmod: fix the lock in register_test_dev_kmod()
  test_kmod: fix bug which allows negative values on two config options
  test_kmod: fix spelling mistake: "EMTPY" -> "EMPTY"
  userfaultfd: hugetlbfs: remove superfluous page unlock in VM_SHARED case
  mm: ratelimit PFNs busy info message
  ...

When the process exit races with outstanding mcopy_atomic, it would be
better to return ESRCH error.  When such race occurs the process and
it's mm are going away and returning "no such process" to the uffd
monitor seems better fit than ENOSPC.

Link: http://lkml.kernel.org/r/1502111545-32305-1-git-send-email-rppt@linux.vnet.ibm.comSigned-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

comp_algorithm_store() passes the size of the source buffer to strlcpy()
instead of the destination buffer size.  Make it explicit that the two
buffers have the same size and use strcpy() instead of strlcpy().  The
latter can be done safely since the function ensures that the string in
the source buffer is terminated.

Link: http://lkml.kernel.org/r/20170803163350.45245-1-mka@chromium.orgSigned-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MMU notifiers can sleep, but in page_mkclean_one() we call
mmu_notifier_invalidate_page() under page table lock.

Let's instead use mmu_notifier_invalidate_range() outside
page_vma_mapped_walk() loop.

[jglisse@redhat.com: try_to_unmap_one() do not call mmu_notifier under ptl]
  Link: http://lkml.kernel.org/r/20170809204333.27485-1-jglisse@redhat.com
Link: http://lkml.kernel.org/r/20170804134928.l4klfcnqatni7vsc@black.fi.intel.com
Fixes: c7ab0d2f ("mm: convert try_to_unmap_one() to use page_vma_mapped_walk()")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reported-by: axie <axie@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Writer, Tim" <Tim.Writer@amd.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We saw many list corruption warnings on shmem shrinklist:

  WARNING: CPU: 18 PID: 177 at lib/list_debug.c:59 __list_del_entry+0x9e/0xc0
  list_del corruption. prev->next should be ffff9ae5694b82d8, but was ffff9ae5699ba960
  Modules linked in: intel_rapl sb_edac edac_core x86_pkg_temp_thermal coretemp iTCO_wdt iTCO_vendor_support crct10dif_pclmul crc32_pclmul ghash_clmulni_intel raid0 dcdbas shpchp wmi hed i2c_i801 ioatdma lpc_ich i2c_smbus acpi_cpufreq tcp_diag inet_diag sch_fq_codel ipmi_si ipmi_devintf ipmi_msghandler igb ptp crc32c_intel pps_core i2c_algo_bit i2c_core dca ipv6 crc_ccitt
  CPU: 18 PID: 177 Comm: kswapd1 Not tainted 4.9.34-t3.el7.twitter.x86_64 #1
  Hardware name: Dell Inc. PowerEdge C6220/0W6W6G, BIOS 2.2.3 11/07/2013
  Call Trace:
    dump_stack+0x4d/0x66
    __warn+0xcb/0xf0
    warn_slowpath_fmt+0x4f/0x60
    __list_del_entry+0x9e/0xc0
    shmem_unused_huge_shrink+0xfa/0x2e0
    shmem_unused_huge_scan+0x20/0x30
    super_cache_scan+0x193/0x1a0
    shrink_slab.part.41+0x1e3/0x3f0
    shrink_slab+0x29/0x30
    shrink_node+0xf9/0x2f0
    kswapd+0x2d8/0x6c0
    kthread+0xd7/0xf0
    ret_from_fork+0x22/0x30

  WARNING: CPU: 23 PID: 639 at lib/list_debug.c:33 __list_add+0x89/0xb0
  list_add corruption. prev->next should be next (ffff9ae5699ba960), but was ffff9ae5694b82d8. (prev=ffff9ae5694b82d8).
  Modules linked in: intel_rapl sb_edac edac_core x86_pkg_temp_thermal coretemp iTCO_wdt iTCO_vendor_support crct10dif_pclmul crc32_pclmul ghash_clmulni_intel raid0 dcdbas shpchp wmi hed i2c_i801 ioatdma lpc_ich i2c_smbus acpi_cpufreq tcp_diag inet_diag sch_fq_codel ipmi_si ipmi_devintf ipmi_msghandler igb ptp crc32c_intel pps_core i2c_algo_bit i2c_core dca ipv6 crc_ccitt
  CPU: 23 PID: 639 Comm: systemd-udevd Tainted: G        W       4.9.34-t3.el7.twitter.x86_64 #1
  Hardware name: Dell Inc. PowerEdge C6220/0W6W6G, BIOS 2.2.3 11/07/2013
  Call Trace:
    dump_stack+0x4d/0x66
    __warn+0xcb/0xf0
    warn_slowpath_fmt+0x4f/0x60
    __list_add+0x89/0xb0
    shmem_setattr+0x204/0x230
    notify_change+0x2ef/0x440
    do_truncate+0x5d/0x90
    path_openat+0x331/0x1190
    do_filp_open+0x7e/0xe0
    do_sys_open+0x123/0x200
    SyS_open+0x1e/0x20
    do_syscall_64+0x61/0x170
    entry_SYSCALL64_slow_path+0x25/0x25

The problem is that shmem_unused_huge_shrink() moves entries from the
global sbinfo->shrinklist to its local lists and then releases the
spinlock.  However, a parallel shmem_setattr() could access one of these
entries directly and add it back to the global shrinklist if it is
removed, with the spinlock held.

The logic itself looks solid since an entry could be either in a local
list or the global list, otherwise it is removed from one of them by
list_del_init().  So probably the race condition is that, one CPU is in
the middle of INIT_LIST_HEAD() but the other CPU calls list_empty()
which returns true too early then the following list_add_tail() sees a
corrupted entry.

list_empty_careful() is designed to fix this situation.

[akpm@linux-foundation.org: add comments]
Link: http://lkml.kernel.org/r/20170803054630.18775-1-xiyou.wangcong@gmail.com
Fixes: 779750d2 ("shmem: split huge pages beyond i_size under memory pressure")
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>