In function nfs_permission:
1. the rcu_read_lock and rcu_read_unlock around nfs_do_access
is unnecessary because the rcu critical data structure is already
protected in subsidiary function nfs_access_get_cached_rcu. No other
data structure needs rcu_read_lock in nfs_do_access.

2. call nfs_do_access once is enough, because:
2-1. when mask has MAY_NOT_BLOCK bit
The second call to nfs_do_access will not happen.

2-2. when mask has no MAY_NOT_BLOCK bit
The second call to nfs_do_access will happen if res == -ECHILD, which
means the first nfs_do_access goes out after statement if (!may_block).
The second call to nfs_do_access will go through this procedure once
again except continue the work after if (!may_block).
But above work can be performed by only one call to nfs_do_access
without mangling the mask flag.

Tested in x86_64
Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

The variable status is being initialized with a value that is never
read and it is being updated later with a new value.  The initialization
is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

When we receive a CB_RECALL_ANY that asks us to return flexfiles
layouts, we iterate through all the layouts and look at whether or
not there are active open file descriptors that might need them
for I/O. If there are no such descriptors, we return the layouts.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Convert to use nfs_client_for_each_server() for efficiency.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Convert nfs_delegation_reap_unclaimed() to use nfs_client_for_each_server()
for efficiency.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Convert it to use the nfs_client_for_each_server() helper, and
make it more efficient by skipping delegations for inodes we
know are in the process of being freed. Also improve the efficiency
of the cursor by skipping delegations that are being freed.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Add a helper nfs_client_for_each_server() to iterate through all the
filesystems that are attached to a struct nfs_client, and apply
a function to all the active ones.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Now that we can rely on just the rcu_read_lock(), remove the
clp->cl_lock and clean up.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Make sure to test the stateid for validity so that we catch instances
where the server may have been reusing stateids in
nfs_layout_find_inode_by_stateid().

Fixes: 7b410d9c ("pNFS: Delay getting the layout header in CB_LAYOUTRECALL handlers")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Ensure that if the DS is returning too many DELAY and GRACE errors, we
also report that to the MDS through the layouterror mechanism.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Currently, we have no real limit on the access cache size (we set it
to ULONG_MAX). That can lead to credentials getting pinned for a
very long time on lots of files if you have a system with a lot of
memory.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

In both async rename and rename, we take a reference to the
cred in the call arguments.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Layoutget is just using the credential attached to the open context.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Avoid unnecessary references to the cred when we have already referenced
it through the open context or the open owner.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

In read/write/commit, we should be able to assume that the cred is
pinned by the open context.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If the RPC call is synchronous, assume the cred is already pinned
by the caller.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Add a flag to signal to the RPC layer that the credential is already
pinned for the duration of the RPC call.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If we're creating a nfs_open_context() for a specific file pointer,
we must use the cred assigned to that file.

Fixes: a52458b4 ("NFS/NFSD/SUNRPC: replace generic creds with 'struct cred'.")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We can't allow delegreturn to hold up nfs4_evict_inode() forever,
since that can cause the memory shrinkers to block. This patch
therefore ensures that we eventually time out, and complete the
reclaim of the inode.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If the cred assigned to the layout that we're updating differs from
the one used to retrieve the new layout segment, then we need to
update the layout plh_lc_cred field.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If the cred assigned to the delegation that we're updating differs
from the one we're updating too, then we need to update that field
too.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

When we're running as a 64-bit architecture and are not running in
32-bit compatibility mode, it is better to use the 64-bit readdir
cookies that supplied by the server. Doing so improves the accuracy
of telldir()/seekdir(), particularly when the directory is changing,
for instance, when doing 'rm -rf'.

We still fall back to using the 32-bit offsets on 32-bit architectures
and when in compatibility mode.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Pull irq fix from Thomas Gleixner:
 "A single commit to handle an erratum in Cavium ThunderX to prevent
  access to GIC registers which are broken in the implementation"

* tag 'irq-urgent-2020-03-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3: Workaround Cavium erratum 38539 when reading GICD_TYPER2

Pull futex fix from Thomas Gleixner:
 "Fix for yet another subtle futex issue.

  The futex code used ihold() to prevent inodes from vanishing, but
  ihold() does not guarantee inode persistence. Replace the inode
  pointer with a per boot, machine wide, unique inode identifier.

  The second commit fixes the breakage of the hash mechanism which
  causes a 100% performance regression"

* tag 'locking-urgent-2020-03-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Unbreak futex hashing
  futex: Fix inode life-time issue

Pull x86 fixes from Thomas Gleixner:
 "Two fixes for x86:

   - Map EFI runtime service data as encrypted when SEV is enabled.

     Otherwise e.g. SMBIOS data cannot be properly decoded by dmidecode.

   - Remove the warning in the vector management code which triggered
     when a managed interrupt affinity changed outside of a CPU hotplug
     operation.

     The warning was correct until the recent core code change that
     introduced a CPU isolation feature which needs to migrate managed
     interrupts away from online CPUs under certain conditions to
     achieve the isolation"

* tag 'x86-urgent-2020-03-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/vector: Remove warning on managed interrupt migration
  x86/ioremap: Map EFI runtime services data as encrypted for SEV

Pull perf fixes from Thomas Gleixner:
 "A pile of perf fixes:

  Kernel side:

   - AMD uncore driver: Replace the open coded sanity check with the
     core variant, which provides the correct error code and also leaves
     a hint in dmesg

  Tooling:

   - Fix the stdio input handling with glibc versions >= 2.28

   - Unbreak the futex-wake benchmark which was reduced to 0 test
     threads due to the conversion to cpumaps

   - Initialize sigaction structs before invoking sys_sigactio()

   - Plug the mapfile memory leak in perf jevents

   - Fix off by one relative directory includes

   - Fix an undefined string comparison in perf diff"

* tag 'perf-urgent-2020-03-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/amd/uncore: Replace manual sampling check with CAP_NO_INTERRUPT flag
  tools: Fix off-by 1 relative directory includes
  perf jevents: Fix leak of mapfile memory
  perf bench: Clear struct sigaction before sigaction() syscall
  perf bench futex-wake: Restore thread count default to online CPU count
  perf top: Fix stdio interface input handling with glibc 2.28+
  perf diff: Fix undefined string comparision spotted by clang's -Wstring-compare
  perf symbols: Don't try to find a vmlinux file when looking for kernel modules
  perf bench: Share some global variables to fix build with gcc 10
  perf parse-events: Use asprintf() instead of strncpy() to read tracepoint files
  perf env: Do not return pointers to local variables
  perf tests bp_account: Make global variable static

Pull timer fix from Thomas Gleixner:
 "A single fix adding the missing time namespace adjustment in
  sys/sysinfo which caused sys/sysinfo to be inconsistent with
  /proc/uptime when read from a task inside a time namespace"

* tag 'timers-urgent-2020-03-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sys/sysinfo: Respect boottime inside time namespace

Pull RAS fixes from Thomas Gleixner:
 "Two RAS related fixes:

   - Shut down the per CPU thermal throttling poll work properly when a
     CPU goes offline.

     The missing shutdown caused the poll work to be migrated to a
     unbound worker which triggered warnings about the usage of
     smp_processor_id() in preemptible context

   - Fix the PPIN feature initialization which missed to enable the
     functionality when PPIN_CTL was enabled but the MSR locked against
     updates"

* tag 'ras-urgent-2020-03-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mce: Fix logic and comments around MSR_PPIN_CTL
  x86/mce/therm_throt: Undo thermal polling properly on CPU offline

Pull EFI fixes from Thomas Gleixner:
 "Two EFI fixes:

   - Prevent a race and buffer overflow in the sysfs efivars interface
     which causes kernel memory corruption.

   - Add the missing NULL pointer checks in efivar_store_raw()"

* tag 'efi-urgent-2020-03-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi: Add a sanity check to efivar_store_raw()
  efi: Fix a race and a buffer overflow while reading efivars via sysfs

Pull IOMMU fixes from Joerg Roedel:

 - Intel VT-d fixes:
    - RCU list handling fixes
    - Replace WARN_TAINT with pr_warn + add_taint for reporting firmware
      issues
    - DebugFS fixes
    - Fix for hugepage handling in iova_to_phys implementation
    - Fix for handling VMD devices, which have a domain number which
      doesn't fit into 16 bits
    - Warning message fix

 - MSI allocation fix for iommu-dma code

 - Sign-extension fix for io page-table code

 - Fix for AMD-Vi to properly update the is-running bit when AVIC is
   used

* tag 'iommu-fixes-v5.6-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/vt-d: Populate debugfs if IOMMUs are detected
  iommu/amd: Fix IOMMU AVIC not properly update the is_run bit in IRTE
  iommu/vt-d: Ignore devices with out-of-spec domain number
  iommu/vt-d: Fix the wrong printing in RHSA parsing
  iommu/vt-d: Fix debugfs register reads
  iommu/vt-d: quirk_ioat_snb_local_iommu: replace WARN_TAINT with pr_warn + add_taint
  iommu/vt-d: dmar_parse_one_rmrr: replace WARN_TAINT with pr_warn + add_taint
  iommu/vt-d: dmar: replace WARN_TAINT with pr_warn + add_taint
  iommu/vt-d: Silence RCU-list debugging warnings
  iommu/vt-d: Fix RCU-list bugs in intel_iommu_init()
  iommu/dma: Fix MSI reservation allocation
  iommu/io-pgtable-arm: Fix IOVA validation for 32-bit
  iommu/vt-d: Fix a bug in intel_iommu_iova_to_phys() for huge page
  iommu/vt-d: Fix RCU list debugging warnings

Merge tag 'irqchip-fixes-5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/urgent

Pull irqchip fixes from Marc Zyngier:

- Add workaround for Cavium/Marvell ThunderX unimplemented GIC registers

Pull i2c fixes from Wolfram Sang:
 "I2C has quite some regression fixes this time.

  One is also related to watchdogs, we have proper acks from Guenter for
  them"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: acpi: put device when verifying client fails
  misc: eeprom: at24: fix regulator underflow
  i2c: gpio: suppress error on probe defer
  macintosh: windfarm: fix MODINFO regression
  i2c: designware-pci: Fix BUG_ON during device removal
  i2c: i801: Do not add ICH_RES_IO_SMI for the iTCO_wdt device
  watchdog: iTCO_wdt: Make ICH_RES_IO_SMI optional
  watchdog: iTCO_wdt: Export vendorsupport

Pull ARC fixes from Vineet Gupta:

 - Fix __ALIGN_STR and __ALIGN to not use default junk padding

 - Misc Kconfig cleanups, header updates

* tag 'arc-5.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: define __ALIGN_STR and __ALIGN symbols for ARC
  ARC: show_regs: reduce lines of output
  ARC: Replace <linux/clk-provider.h> by <linux/of_clk.h>
  ARC: fpu: fix randconfig build error reported by 0-day test service
  ARC: fix some Kconfig typos
  ARC: Cleanup old Kconfig IO scheduler options

Pull kvm fixes from Paolo Bonzini:
 "Bugfixes for x86 and s390"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: nVMX: avoid NULL pointer dereference with incorrect EVMCS GPAs
  KVM: x86: Initializing all kvm_lapic_irq fields in ioapic_write_indirect
  KVM: VMX: Condition ENCLS-exiting enabling on CPU support for SGX1
  KVM: s390: Also reset registers in sync regs for initial cpu reset
  KVM: fix Kconfig menu text for -Werror
  KVM: x86: remove stale comment from struct x86_emulate_ctxt
  KVM: x86: clear stale x86_emulate_ctxt->intercept value
  KVM: SVM: Fix the svm vmexit code for WRMSR
  KVM: X86: Fix dereference null cpufreq policy

Currently, the intel iommu debugfs directory(/sys/kernel/debug/iommu/intel)
gets populated only when DMA remapping is enabled (dmar_disabled = 0)
irrespective of whether interrupt remapping is enabled or not.

Instead, populate the intel iommu debugfs directory if any IOMMUs are
detected.

Cc: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: ee2636b8 ("iommu/vt-d: Enable base Intel IOMMU debugfs support")
Signed-off-by: Megha Dey <megha.dey@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Pull clk fixes from Stephen Boyd:
 "A small collection of fixes. I'll make another sweep soon to look for
  more fixes for this -rc series.

   - Mark device node const in of_clk_get_parent APIs to ease landing
     changes in users later

   - Fix flag for Qualcomm SC7180 video clocks where we thought it would
     never turn off but actually hardware takes care of it

   - Remove disp_cc_mdss_rscc_ahb_clk on Qualcomm SC7180 SoCs because
     this clk is always on anyway

   - Correct some bad dt-binding numbers for i.MX8MN SoCs"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: imx8mn: Fix incorrect clock defines
  clk: qcom: dispcc: Remove support of disp_cc_mdss_rscc_ahb_clk
  clk: qcom: videocc: Update the clock flag for video_cc_vcodec0_core_clk
  of: clk: Make of_clk_get_parent_{count,name}() parameter const

When an EVMCS enabled L1 guest on KVM will tries doing enlightened VMEnter
with EVMCS GPA = 0 the host crashes because the

evmcs_gpa != vmx->nested.hv_evmcs_vmptr

condition in nested_vmx_handle_enlightened_vmptrld() will evaluate to
false (as nested.hv_evmcs_vmptr is zeroed after init). The crash will
happen on vmx->nested.hv_evmcs pointer dereference.

Another problematic EVMCS ptr value is '-1' but it only causes host crash
after nested_release_evmcs() invocation. The problem is exactly the same as
with '0', we mistakenly think that the EVMCS pointer hasn't changed and
thus nested.hv_evmcs_vmptr is valid.

Resolve the issue by adding an additional !vmx->nested.hv_evmcs
check to nested_vmx_handle_enlightened_vmptrld(), this way we will
always be trying kvm_vcpu_map() when nested.hv_evmcs is NULL
and this is supposed to catch all invalid EVMCS GPAs.

Also, initialize hv_evmcs_vmptr to '0' in nested_release_evmcs()
to be consistent with initialization where we don't currently
set hv_evmcs_vmptr to '-1'.

Cc: stable@vger.kernel.org
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>