Merge thundering herd avoidance on pipe IO.

This would have been applied for 5.5 already, but got delayed because of
a user-space race condition in the GNU make jobserver code.  Now that
there's a new GNU make 4.3 release, and most distributions seem to have
at least applied the (almost three year old) fix for the problem, let's
see if people notice.

And it might have been just bad random timing luck on my machine.

If you do hit the race condition, things will still work, but the
symptom is that you don't get nearly the expected parallelism when using
"make -j<N>".

The jobserver bug can definitely happen without this patch too, but
seems to be easier to trigger when we no longer wake up pipe waiters
unnecessarily.

* pipe-exclusive-wakeup:
  pipe: use exclusive waits when reading or writing

This makes the pipe code use separate wait-queues and exclusive waiting
for readers and writers, avoiding a nasty thundering herd problem when
there are lots of readers waiting for data on a pipe (or, less commonly,
lots of writers waiting for a pipe to have space).

While this isn't a common occurrence in the traditional "use a pipe as a
data transport" case, where you typically only have a single reader and
a single writer process, there is one common special case: using a pipe
as a source of "locking tokens" rather than for data communication.

In particular, the GNU make jobserver code ends up using a pipe as a way
to limit parallelism, where each job consumes a token by reading a byte
from the jobserver pipe, and releases the token by writing a byte back
to the pipe.

This pattern is fairly traditional on Unix, and works very well, but
will waste a lot of time waking up a lot of processes when only a single
reader needs to be woken up when a writer releases a new token.

A simplified test-case of just this pipe interaction is to create 64
processes, and then pass a single token around between them (this
test-case also intentionally passes another token that gets ignored to
test the "wake up next" logic too, in case anybody wonders about it):

    #include <unistd.h>

    int main(int argc, char **argv)
    {
        int fd[2], counters[2];

        pipe(fd);
        counters[0] = 0;
        counters[1] = -1;
        write(fd[1], counters, sizeof(counters));

        /* 64 processes */
        fork(); fork(); fork(); fork(); fork(); fork();

        do {
                int i;
                read(fd[0], &i, sizeof(i));
                if (i < 0)
                        continue;
                counters[0] = i+1;
                write(fd[1], counters, (1+(i & 1)) *sizeof(int));
        } while (counters[0] < 1000000);
        return 0;
    }

and in a perfect world, passing that token around should only cause one
context switch per transfer, when the writer of a token causes a
directed wakeup of just a single reader.

But with the "writer wakes all readers" model we traditionally had, on
my test box the above case causes more than an order of magnitude more
scheduling: instead of the expected ~1M context switches, "perf stat"
shows

        231,852.37 msec task-clock                #   15.857 CPUs utilized
        11,250,961      context-switches          #    0.049 M/sec
           616,304      cpu-migrations            #    0.003 M/sec
             1,648      page-faults               #    0.007 K/sec
 1,097,903,998,514      cycles                    #    4.735 GHz
   120,781,778,352      instructions              #    0.11  insn per cycle
    27,997,056,043      branches                  #  120.754 M/sec
       283,581,233      branch-misses             #    1.01% of all branches

      14.621273891 seconds time elapsed

       0.018243000 seconds user
       3.611468000 seconds sys

before this commit.

After this commit, I get

          5,229.55 msec task-clock                #    3.072 CPUs utilized
         1,212,233      context-switches          #    0.232 M/sec
           103,951      cpu-migrations            #    0.020 M/sec
             1,328      page-faults               #    0.254 K/sec
    21,307,456,166      cycles                    #    4.074 GHz
    12,947,819,999      instructions              #    0.61  insn per cycle
     2,881,985,678      branches                  #  551.096 M/sec
        64,267,015      branch-misses             #    2.23% of all branches

       1.702148350 seconds time elapsed

       0.004868000 seconds user
       0.110786000 seconds sys

instead. Much better.

[ Note! This kernel improvement seems to be very good at triggering a
  race condition in the make jobserver (in GNU make 4.2.1) for me. It's
  a long known bug that was fixed back in June 2017 by GNU make commit
  b552b0525198 ("[SV 51159] Use a non-blocking read with pselect to
  avoid hangs.").

  But there wasn't a new release of GNU make until 4.3 on Jan 19 2020,
  so a number of distributions may still have the buggy version. Some
  have backported the fix to their 4.2.1 release, though, and even
  without the fix it's quite timing-dependent whether the bug actually
  is hit. ]

Josh Triplett says:
 "I've been hammering on your pipe fix patch (switching to exclusive
  wait queues) for a month or so, on several different systems, and I've
  run into no issues with it. The patch *substantially* improves
  parallel build times on large (~100 CPU) systems, both with parallel
  make and with other things that use make's pipe-based jobserver.

  All current distributions (including stable and long-term stable
  distributions) have versions of GNU make that no longer have the
  jobserver bug"
Tested-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull fuse fixes from Miklos Szeredi:

 - Fix a regression introduced in v5.1 that triggers WARNINGs for some
   fuse filesystems

 - Fix an xfstest failure

 - Allow overlayfs to be used on top of fuse/virtiofs

 - Code and documentation cleanups

* tag 'fuse-fixes-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: use true,false for bool variable
  Documentation: filesystems: convert fuse to RST
  fuse: Support RENAME_WHITEOUT flag
  fuse: don't overflow LLONG_MAX with end offset
  fix up iter on short count in fuse_direct_io()

Pull gfs2 fixes from Andreas Gruenbacher:

 - Fix a bug in Abhi Das's journal head lookup improvements that can
   cause a valid journal to be rejected.

 - Fix an O_SYNC write handling bug reported by Christoph Hellwig.

* tag 'gfs2-for-5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: fix O_SYNC write handling
  gfs2: move setting current->backing_dev_info
  gfs2: fix gfs2_find_jhead that returns uninitialized jhead with seq 0

Pull orangefs fix from Mike Marshall:
 "Debugfs fix for orangefs.

  Vasliy Averin noticed that 'if seq_file .next function does not change
  position index, read after some lseek can generate unexpected output'
  and sent in this fix"

* tag 'for-linus-5.6-ofs1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux:
  help_next should increase position index

Pull nfsd updates from Bruce Fields:
 "Highlights:

   - Server-to-server copy code from Olga.

     To use it, client and both servers must have support, the target
     server must be able to access the source server over NFSv4.2, and
     the target server must have the inter_copy_offload_enable module
     parameter set.

   - Improvements and bugfixes for the new filehandle cache, especially
     in the container case, from Trond

   - Also from Trond, better reporting of write errors.

   - Y2038 work from Arnd"

* tag 'nfsd-5.6' of git://linux-nfs.org/~bfields/linux: (55 commits)
  sunrpc: expiry_time should be seconds not timeval
  nfsd: make nfsd_filecache_wq variable static
  nfsd4: fix double free in nfsd4_do_async_copy()
  nfsd: convert file cache to use over/underflow safe refcount
  nfsd: Define the file access mode enum for tracing
  nfsd: Fix a perf warning
  nfsd: Ensure sampling of the write verifier is atomic with the write
  nfsd: Ensure sampling of the commit verifier is atomic with the commit
  sunrpc: clean up cache entry add/remove from hashtable
  sunrpc: Fix potential leaks in sunrpc_cache_unhash()
  nfsd: Ensure exclusion between CLONE and WRITE errors
  nfsd: Pass the nfsd_file as arguments to nfsd4_clone_file_range()
  nfsd: Update the boot verifier on stable writes too.
  nfsd: Fix stable writes
  nfsd: Allow nfsd_vfs_write() to take the nfsd_file as an argument
  nfsd: Fix a soft lockup race in nfsd_file_mark_find_or_create()
  nfsd: Reduce the number of calls to nfsd_file_gc()
  nfsd: Schedule the laundrette regularly irrespective of file errors
  nfsd: Remove unused constant NFSD_FILE_LRU_RESCAN
  nfsd: Containerise filecache laundrette
  ...

Puyll NFS client updates from Anna Schumaker:
 "Stable bugfixes:
   - Fix memory leaks and corruption in readdir # v2.6.37+
   - Directory page cache needs to be locked when read # v2.6.37+

  New features:
   - Convert NFS to use the new mount API
   - Add "softreval" mount option to let clients use cache if server goes down
   - Add a config option to compile without UDP support
   - Limit the number of inactive delegations the client can cache at once
   - Improved readdir concurrency using iterate_shared()

  Other bugfixes and cleanups:
   - More 64-bit time conversions
   - Add additional diagnostic tracepoints
   - Check for holes in swapfiles, and add dependency on CONFIG_SWAP
   - Various xprtrdma cleanups to prepare for 5.7's changes
   - Several fixes for NFS writeback and commit handling
   - Fix acls over krb5i/krb5p mounts
   - Recover from premature loss of openstateids
   - Fix NFS v3 chacl and chmod bug
   - Compare creds using cred_fscmp()
   - Use kmemdup_nul() in more places
   - Optimize readdir cache page invalidation
   - Lease renewal and recovery fixes"

* tag 'nfs-for-5.6-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (93 commits)
  NFSv4.0: nfs4_do_fsinfo() should not do implicit lease renewals
  NFSv4: try lease recovery on NFS4ERR_EXPIRED
  NFS: Fix memory leaks
  nfs: optimise readdir cache page invalidation
  NFS: Switch readdir to using iterate_shared()
  NFS: Use kmemdup_nul() in nfs_readdir_make_qstr()
  NFS: Directory page cache pages need to be locked when read
  NFS: Fix memory leaks and corruption in readdir
  SUNRPC: Use kmemdup_nul() in rpc_parse_scope_id()
  NFS: Replace various occurrences of kstrndup() with kmemdup_nul()
  NFSv4: Limit the total number of cached delegations
  NFSv4: Add accounting for the number of active delegations held
  NFSv4: Try to return the delegation immediately when marked for return on close
  NFS: Clear NFS_DELEGATION_RETURN_IF_CLOSED when the delegation is returned
  NFSv4: nfs_inode_evict_delegation() should set NFS_DELEGATION_RETURNING
  NFS: nfs_find_open_context() should use cred_fscmp()
  NFS: nfs_access_get_cached_rcu() should use cred_fscmp()
  NFSv4: pnfs_roc() must use cred_fscmp() to compare creds
  NFS: remove unused macros
  nfs: Return EINVAL rather than ERANGE for mount parse errors
  ...

Pull Documentation fixes from Jonathan Corbet:
 "A handful of small documentation fixes that wandered in"

* tag 'docs-5.6-2' of git://git.lwn.net/linux:
  Allow git builds of Sphinx
  Documentation: changes.rst: update several outdated project URLs
  Documentation: build warnings related to missing blank lines after explicit markups has been fixed
  mailmap: add entry for Tiezhu Yang
  Documentation/ko_KR/howto: Update a broken link
  Documentation/ko_KR/howto: Update broken web addresses
  docs/locking: Fix outdated section names

Pull i2c updates from Wolfram Sang:
 "i2c core:

   - huge improvements and refactorizations of the Linux I2C
     documentation (lots of thanks to Luca for doing it and Jean for the
     careful review)

   - subsystem wide API conversion to i2c_new_client_device()

   - remove obsolete parport-light driver

   - smaller core updates (removal of 'extern', enabling more compile
     testing, use more helper macros)

   - and quite a bunch of driver updates (new IDs, simplifications,
     better PM, support of atomic transfers and other improvements)

  i2c-mux:

   - The main feature is the idle-state rework of the pca954x driver
     from Biwen Li

  at24 driver:

   - minor maintenance: update the license tag, sort headers

   - move support for the write-protect pin into nvmem core

   - add a reference to the new wp-gpios property in nvmem to at25
     bindings

   - add support for regulator and pm_runtime control"

* 'i2c/for-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (91 commits)
  i2c: cros-ec-tunnel: Fix ACPI identifier
  i2c: cros-ec-tunnel: Fix slave device enumeration
  i2c: stm32f7: add PM_SLEEP suspend/resume support
  i2c: cadence: Fix wording in i2c-cadence driver
  i2c: cadence: Fix power management order of operations
  i2c: cadence: Fix error printing in case of defer
  i2c: cadence: Handle transfer_size rollover
  i2c: i801: Add support for Intel Comet Lake PCH-V
  docs: i2c: writing-clients: properly name the stop condition
  docs: i2c: i2c-protocol: use same wording as smbus-protocol
  docs: i2c: rename sections so the overall picture is clearer
  docs: i2c: old-module-parameters: use monospace instead of ""
  docs: i2c: old-module-parameters: clarify this is for obsolete kernels
  docs: i2c: old-module-parameters: fix internal hyperlink
  docs: i2c: instantiating-devices: use monospace for sysfs attributes
  docs: i2c: instantiating-devices: rearrange static instatiation
  docs: i2c: instantiating-devices: fix internal hyperlink
  docs: i2c: smbus-protocol: improve I2C Block transactions description
  docs: i2c: smbus-protocol: fix punctuation
  docs: i2c: smbus-protocol: fix typo
  ...

Pull more ACPI updates from Rafael Wysocki:
 "Add Hisilicon Hip08-Lite I2C controller clock frequency support to the
  ACPI driver for AMD SoCs (APD) and to the Designware I2C driver
  (Hanjun Guo)"

* tag 'acpi-5.6-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  i2c: designware: Add ACPI HID for Hisilicon Hip08-Lite I2C controller
  ACPI / APD: Add clock frequency for Hisilicon Hip08-Lite I2C controller

Pull more power management updates from Rafael Wysocki:

 - Update the recently merged CPR (Core Power Reduction) support in the
   AVS (Adaptive Voltage Scaling) subsystem (Brendan Higgins, Nathan
   Chancellor, Niklas Cassel)

 - Update the rockchip-io AVS driver (Heiko Stuebner)

 - Add two more module parameters to intel_idle on top of the recently
   merged material (Rafael Wysocki)

 - Clean up a piece of cpuidle documentation and consolidate system
   sleep states documentation (Rafael Wysocki)

* tag 'pm-5.6-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpuidle: Documentation: Clean up PM QoS description
  Documentation: admin-guide: PM: Update sleep states documentation
  intel_idle: Introduce 'states_off' module parameter
  intel_idle: Introduce 'use_acpi' module parameter
  power: avs: qcom-cpr: Avoid clang -Wsometimes-uninitialized in cpr_scale
  power: avs: qcom-cpr: add unspecified HAS_IOMEM dependency
  PM / AVS: rockchip-io: fix the supply naming for the emmc supply on px30
  power: avs: qcom-cpr: add a printout after the driver has been initialized

Pull drm fixes from Dave Airlie:
 "Just some fixes for this merge window: the tegra changes fix some
  regressions in the merge, nouveau has a few modesetting fixes.

  The amdgpu fixes are bit bigger, but they contain a couple of weeks of
  fixes, and don't seem to contain anything that isn't really a fix.

  Summary:

  tegra:
   - merge window regression fixes

  nouveau:
   - couple of volta/turing modesetting fixes

  amdgpu:
   - EDC fixes for Arcturus
   - GDDR6 memory training fixe
   - Fix for reading gfx clockgating registers while in GFXOFF state
   - i2c freq fixes
   - Misc display fixes
   - TLB invalidation fix when using semaphores
   - VCN 2.5 instancing fixes
   - Switch raven1 gfxoff to a blacklist
   - Coreboot workaround for KV/KB
   - Root cause dongle fixes for display and revert workaround
   - Enable GPU reset for renoir and navi
   - Navi overclocking fixes
   - Fix up confusing warnings in display clock validation on raven

  amdkfd:
   - SDMA fix

  radeon:
   - Misc LUT fixes"

* tag 'drm-next-2020-02-07' of git://anongit.freedesktop.org/drm/drm: (90 commits)
  gpu: host1x: Set DMA direction only for DMA-mapped buffer objects
  drm/tegra: Reuse IOVA mapping where possible
  drm/tegra: Relax IOMMU usage criteria on old Tegra
  drm/amd/dm/mst: Ignore payload update failures
  drm/amdgpu: update default voltage for boot od table for navi1x
  drm/amdgpu/smu10: fix smu10_get_clock_by_type_with_voltage
  drm/amdgpu/smu10: fix smu10_get_clock_by_type_with_latency
  drm/amdgpu/display: handle multiple numbers of fclks in dcn_calcs.c (v2)
  drm/amdgpu: fetch default VDDC curve voltages (v2)
  drm/amdgpu/smu_v11_0: Correct behavior of restoring default tables (v2)
  drm/amdgpu/navi10: add OD_RANGE for navi overclocking
  drm/amdgpu/navi: fix index for OD MCLK
  drm/amd/display: Fix HW/SW state mismatch
  drm/amd/display: Fix a typo when computing dsc configuration
  drm/amd/powerplay: fix navi10 system intermittent reboot issue V2
  drm/amdkfd: Fix a bug in SDMA RLC queue counting under HWS mode
  drm/amd/display: Only enable cursor on pipes that need it
  drm/nouveau/kms/gv100-: avoid sending a core update until the first modeset
  drm/nouveau/kms/gv100-: move window ownership setup into modesetting path
  drm/nouveau/disp/gv100-: halt NV_PDISP_FE_RM_INTR_STAT_CTRL_DISP_ERROR storms
  ...

Pull clk fixes from Stephen Boyd:
 "A collection of fixes:

   - Make of_clk.h self contained

   - Fix new qcom DT bindings that just merged to match the DTS files

   - Fix qcom clk driver to properly detect DFS clk frequencies

   - Fix the ls1028a driver to not deref a pointer before assigning it"

* tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  of: clk: Make <linux/of_clk.h> self-contained
  clk: qcom: Use ARRAY_SIZE in videocc-sc7180 for parent clocks
  clk: qcom: Get rid of the test clock for videocc-sc7180
  dt-bindings: clock: Cleanup qcom,videocc bindings for sdm845/sc7180
  clk: qcom: Use ARRAY_SIZE in gpucc-sc7180 for parent clocks
  clk: qcom: Get rid of the test clock for gpucc-sc7180
  dt-bindings: clock: Fix qcom,gpucc bindings for sdm845/sc7180/msm8998
  clk: qcom: Use ARRAY_SIZE in dispcc-sc7180 for parent clocks
  clk: qcom: Get rid of the test clock for dispcc-sc7180
  clk: qcom: Get rid of fallback global names for dispcc-sc7180
  dt-bindings: clock: Fix qcom,dispcc bindings for sdm845/sc7180
  clk: qcom: rcg2: Don't crash if our parent can't be found; return an error
  clk: ls1028a: fix a dereference of pointer 'parent' before a null check
  dt-bindings: clk: qcom: Fix self-validation, split, and clean cruft
  clk: qcom: Don't overwrite 'cfg' in clk_rcg2_dfs_populate_freq()

Pull watchdog updates from Wim Van Sebroeck:

 - add IT8786 chipset ID

 - addition of sam9x60 compatible watchdog

 - da9062 improvements

 - fix UAF in reboot notifier handling in watchdog core code

 - other fixes and small improvements

* tag 'linux-watchdog-5.6-rc1' of git://www.linux-watchdog.org/linux-watchdog:
  watchdog: da9062: make restart handler atomic safe
  watchdog: mtk_wdt: mt2712: Add reset controller
  watchdog: mtk_wdt: mt8183: Add reset controller
  dt-bindings: mediatek: mt2712: Add #reset-cells
  dt-bindings: mediatek: mt8183: Add #reset-cells
  dt-bindings: watchdog: da9062: add suspend disable option
  watchdog: it87_wdt: add IT8786 ID
  watchdog: dw_wdt: ping watchdog to reset countdown before start
  watchdog: fix UAF in reboot notifier handling in watchdog core code
  watchdog: cadence: Skip printing pointer value
  watchdog: qcom: Use platform_get_irq_optional() for bark irq
  watchdog: da9062: add power management ops
  watchdog: make DesignWare watchdog allow users to set bigger timeout value
  drivers: watchdog: stm32_iwdg: set WDOG_HW_RUNNING at probe
  watchdog: sama5d4_wdt: addition of sam9x60 compatible watchdog

Pull virtio updates from Michael Tsirkin:
 "Some bug fixes/cleanups.

  The deprecated scsi passthrough for virtio_blk is removed"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio_balloon: Fix memory leaks on errors in virtballoon_probe()
  virtio-balloon: Fix memory leak when unloading while hinting is in progress
  virtio_balloon: prevent pfn array overflow
  virtio-blk: remove VIRTIO_BLK_F_SCSI support
  virtio-pci: check name when counting MSI-X vectors
  virtio-balloon: initialize all vq callbacks
  virtio-mmio: convert to devm_platform_ioremap_resource

Pull xtensa updates from Max Filippov:

 - reorganize exception vectors placement

 - small cleanups (drop unused functions/headers/defconfig entries,
   spelling fixes)

* tag 'xtensa-20200206' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: ISS: improve simcall assembly
  xtensa: reorganize vectors placement
  xtensa: separate SMP and XIP support
  xtensa: move fast exception handlers close to vectors
  arch/xtensa: fix Kconfig typos for HAVE_SMP
  xtensa: clean up optional XCHAL_* definitions
  xtensa: drop unused function fast_coprocessor_double
  xtensa: drop empty platform_* functions from platforms
  xtensa: clean up platform headers
  xtensa: drop set_except_vector declaration
  xtensa: configs: Cleanup old Kconfig IO scheduler options

When upcalling gssproxy, cache_head.expiry_time is set as a
timeval, not seconds since boot. As such, RPC cache expiry
logic will not clean expired objects created under
auth.rpcsec.context cache.

This has proven to cause kernel memory leaks on field. Using
64 bit variants of getboottime/timespec

Expiration times have worked this way since 2010's c5b29f88 "sunrpc:
use seconds since boot in expiry cache".  The gssproxy code introduced
in 2012 added gss_proxy_save_rsc and introduced the bug.  That's a while
for this to lurk, but it required a bit of an extreme case to make it
obvious.
Signed-off-by: Roberto Bergantinos Corpas <rbergant@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 030d794b "SUNRPC: Use gssproxy upcall for server..."
Tested-By: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Fix sparse warning:

fs/nfsd/filecache.c:55:25: warning:
	symbol 'nfsd_filecache_wq' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

* pm-avs:
  power: avs: qcom-cpr: Avoid clang -Wsometimes-uninitialized in cpr_scale
  power: avs: qcom-cpr: add unspecified HAS_IOMEM dependency
  PM / AVS: rockchip-io: fix the supply naming for the emmc supply on px30
  power: avs: qcom-cpr: add a printout after the driver has been initialized

* pm-cpuidle:
  cpuidle: Documentation: Clean up PM QoS description
  intel_idle: Introduce 'states_off' module parameter
  intel_idle: Introduce 'use_acpi' module parameter

amd-drm-next-5.6-2020-02-05:

amdgpu:
- EDC fixes for Arcturus
- GDDR6 memory training fixe
- Fix for reading gfx clockgating registers while in GFXOFF state
- i2c freq fixes
- Misc display fixes
- TLB invalidation fix when using semaphores
- VCN 2.5 instancing fixes
- Switch raven1 gfxoff to a blacklist
- Coreboot workaround for KV/KB
- Root cause dongle fixes for display and revert workaround
- Enable GPU reset for renoir and navi
- Navi overclocking fixes
- Fix up confusing warnings in display clock validation on raven

amdkfd:
- SDMA fix

radeon:
- Misc LUT fixes
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Alex Deucher <alexdeucher@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200206035458.3894-1-alexander.deucher@amd.com

Just a couple of fixes to Volta/Turing modesetting on some systems.
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Ben Skeggs <skeggsb@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ <CACAvsv7=eP+Ai1ouoMyYyo1xMF0pTQki=owYjJkS=NpvKQd1fg@mail.gmail.com

drm/tegra: Fixes for v5.6-rc1

These are a couple of quick fixes for regressions that were found during
the first two weeks of the merge window.
Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Thierry Reding <thierry.reding@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200206172753.2185390-1-thierry.reding@gmail.com

In gfs2_file_write_iter, for direct writes, the error checking in the buffered
write fallback case is incomplete.  This can cause inode write errors to go
undetected.  Fix and clean up gfs2_file_write_iter along the way.

Based on a proposed fix by Christoph Hellwig <hch@lst.de>.

Fixes: 967bcc91 ("gfs2: iomap direct I/O support")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

The DMA direction is only used by the DMA API, so there is no use in
setting it when a buffer object isn't mapped with the DMA API.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>

This partially reverts the DMA API support that was recently merged
because it was causing performance regressions on older Tegra devices.
Unfortunately, the cache maintenance performed by dma_map_sg() and
dma_unmap_sg() causes performance to drop by a factor of 10.

The right solution for this would be to cache mappings for buffers per
consumer device, but that's a bit involved. Instead, we simply revert to
the old behaviour of sharing IOVA mappings when we know that devices can
do so (i.e. they share the same IOMMU domain).

Cc: <stable@vger.kernel.org> # v5.5
Reported-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>

Older Tegra devices only allow addressing 32 bits of memory, so whether
or not the host1x is attached to an IOMMU doesn't matter. host1x IOMMU
attachment is only needed on devices that can address memory beyond the
32-bit boundary and where the host1x doesn't support the wide GATHER
opcode that allows it to access buffers at higher addresses.

Cc: <stable@vger.kernel.org> # v5.5
Signed-off-by: Thierry Reding <treding@nvidia.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>

Pull more KVM updates from Paolo Bonzini:
 "s390:
   - fix register corruption
   - ENOTSUPP/EOPNOTSUPP mixed
   - reset cleanups/fixes
   - selftests

  x86:
   - Bug fixes and cleanups
   - AMD support for APIC virtualization even in combination with
     in-kernel PIT or IOAPIC.

  MIPS:
   - Compilation fix.

  Generic:
   - Fix refcount overflow for zero page"

* tag 'kvm-5.6-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (42 commits)
  KVM: vmx: delete meaningless vmx_decache_cr0_guest_bits() declaration
  KVM: x86: Mark CR4.UMIP as reserved based on associated CPUID bit
  x86: vmxfeatures: rename features for consistency with KVM and manual
  KVM: SVM: relax conditions for allowing MSR_IA32_SPEC_CTRL accesses
  KVM: x86: Fix perfctr WRMSR for running counters
  x86/kvm/hyper-v: don't allow to turn on unsupported VMX controls for nested guests
  x86/kvm/hyper-v: move VMX controls sanitization out of nested_enable_evmcs()
  kvm: mmu: Separate generating and setting mmio ptes
  kvm: mmu: Replace unsigned with unsigned int for PTE access
  KVM: nVMX: Remove stale comment from nested_vmx_load_cr3()
  KVM: MIPS: Fold comparecount_func() into comparecount_wakeup()
  KVM: MIPS: Fix a build error due to referencing not-yet-defined function
  x86/kvm: do not setup pv tlb flush when not paravirtualized
  KVM: fix overflow of zero page refcount with ksm running
  KVM: x86: Take a u64 when checking for a valid dr7 value
  KVM: x86: use raw clock values consistently
  KVM: x86: reorganize pvclock_gtod_data members
  KVM: nVMX: delete meaningless nested_vmx_run() declaration
  KVM: SVM: allow AVIC without split irqchip
  kvm: ioapic: Lazy update IOAPIC EOI
  ...

Pull kgdb fix from Daniel Thompson:
 "One of the simplifications added for 5.6-rc1 has caused build
  regressions on some platforms (it was reported for sparc64).

  This fixes it with a revert"

* tag 'kgdb-fixes-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
  Revert "kdb: Get rid of confusing diag msg from "rd" if current task has no regs"

Set current->backing_dev_info just around the buffered write calls to
prepare for the next fix.

Fixes: 967bcc91 ("gfs2: iomap direct I/O support")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

When the first log header in a journal happens to have a sequence
number of 0, a bug in gfs2_find_jhead() causes it to prematurely exit,
and return an uninitialized jhead with seq 0. This can cause failures
in the caller. For instance, a mount fails in one test case.

The correct behavior is for it to continue searching through the journal
to find the correct journal head with the highest sequence number.

Fixes: f4686c26 ("gfs2: read journal in large chunks")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Abhi Das <adas@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

This frees "copy->nf_src" before and again after the goto.

Fixes: ce0887ac ("NFSD add nfs4 inter ssc to nfsd4_copy")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Use the 'refcount_t' type instead of 'atomic_t' for improved
refcounting safety.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

perf does not know how to deal with a __builtin_bswap32() call, and
complains. All other functions just store the xid etc in host endian
form, so let's do that in the tracepoint for nfsd_file_acquire too.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Fixes coccicheck warning:

fs/fuse/readdir.c:335:1-19: WARNING: Assignment of 0/1 to bool variable
fs/fuse/file.c:1398:2-19: WARNING: Assignment of 0/1 to bool variable
fs/fuse/file.c:1400:2-20: WARNING: Assignment of 0/1 to bool variable
fs/fuse/cuse.c:454:1-20: WARNING: Assignment of 0/1 to bool variable
fs/fuse/cuse.c:455:1-19: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:497:2-17: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:504:2-23: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:511:2-22: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:518:2-23: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:522:2-26: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:526:2-18: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:1000:1-20: WARNING: Assignment of 0/1 to bool variable
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

Converts fuse.txt to reStructuredText format, improving the presentation
without changing much of the underlying content.
Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

Allow fuse to pass RENAME_WHITEOUT to fuse server.  Overlayfs on top of
virtiofs uses RENAME_WHITEOUT.

Without this patch renaming a directory in overlayfs (dir is on lower)
fails with -EINVAL. With this patch it works.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

Handle the special case of fuse_readpages() wanting to read the last page
of a hugest file possible and overflowing the end offset in the process.

This is basically to unbreak xfstests:generic/525 and prevent filesystems
from doing bad things with an overflowing offset.
Reported-by: Xiao Yang <ice_yangxiao@163.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fuse_direct_io() can end up advancing the iterator by more than the amount
of data read or written.  This case is handled by the generic code if going
through ->direct_IO(), but not in the FOPEN_DIRECT_IO case.

Fix by reverting the extra bytes from the iterator in case of error or a
short count.

To test: install lxcfs, then the following testcase
  int fd = open("/var/lib/lxcfs/proc/uptime", O_RDONLY);
  sendfile(1, fd, NULL, 16777216);
  sendfile(1, fd, NULL, 16777216);
will spew WARN_ON() in iov_iter_pipe().
Reported-by: Peter Geis <pgwipeout@gmail.com>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes: 3c3db095 ("fuse: use iov_iter based generic splice helpers")
Cc: <stable@vger.kernel.org> # v5.1
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

Pull PCI fixes from Bjorn Helgaas:

 - Define to_pci_sysdata() always to fix build breakage when !CONFIG_PCI
   (Jason A. Donenfeld)

 - Use PF PASID for VFs to fix VF IOMMU bind failures (Kuppuswamy
   Sathyanarayanan)

* tag 'pci-v5.6-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI/ATS: Use PF PASID for VFs
  x86/PCI: Define to_pci_sysdata() even when !CONFIG_PCI