xprt_sock_sendmsg uses the more efficient iov_iter-enabled kernel
socket API, and is a pre-requisite for server send-side support for
TLS.

Note that svc_process no longer needs to reserve a word for the
stream record marker, since the TCP transport now provides the
record marker automatically in a separate buffer.

The dprintk() in svc_send_common is also removed. It didn't seem
crucial for field troubleshooting. If more is needed there, a trace
point could be added in xprt_sock_sendmsg().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Re-locate xs_sendpages() so that it can be shared with server code.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

On some platforms, DMA mapping part of a page is more costly than
copying bytes. Indeed, not involving the I/O MMU can help the
RPC/RDMA transport scale better for tiny I/Os across more RDMA
devices. This is because interaction with the I/O MMU is eliminated
for each of these small I/Os. Without the explicit unmapping, the
NIC no longer needs to do a costly internal TLB shoot down for
buffers that are just a handful of bytes.

Since pull-up is now a more a frequent operation, I've introduced a
trace point in the pull-up path. It can be used for debugging or
user-space tools that count pull-up frequency.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Performance optimization: Avoid syncing the transport buffer twice
when Reply buffer pull-up is necessary.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Same idea as the receive-side changes I did a while back: use
xdr_stream helpers rather than open-coding the XDR chunk list
encoders. This builds the Reply transport header from beginning to
end without backtracking.

As additional clean-ups, fill in documenting comments for the XDR
encoders and sprinkle some trace points in the new encoding
functions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Clean up. These are taken from the client-side RPC/RDMA transport
to a more global header file so they can be used elsewhere.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

These trace points are misnamed:

	trace_svcrdma_encode_wseg
	trace_svcrdma_encode_write
	trace_svcrdma_encode_reply
	trace_svcrdma_encode_rseg
	trace_svcrdma_encode_read
	trace_svcrdma_encode_pzr

Because they actually trace posting on the Send Queue. Let's rename
them so that I can add trace points in the chunk list encoders that
actually do trace chunk list encoding events.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Preparing for subsequent patches, no behavior change expected.

Pass the RPC Call's svc_rdma_recv_ctxt deeper into the sendto()
path. This enables passing more information about Requester-
provided Write and Reply chunks into those lower-level functions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Preparing for subsequent patches, no behavior change expected.

Pass the RPC Call's svc_rdma_recv_ctxt deeper into the sendto()
path. This enables passing more information about Requester-
provided Write and Reply chunks into those lower-level functions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Preparing for subsequent patches, no behavior change expected.

Pass the RPC Call's svc_rdma_recv_ctxt deeper into the sendto()
path. This enables passing more information about Requester-
provided Write and Reply chunks into the lower-level send
functions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Cache the locations of the Requester-provided Write list and Reply
chunk so that the Send path doesn't need to parse the Call header
again.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

The logic that checks incoming network headers has to be scrupulous.

De-duplicate: replace open-coded buffer overflow checks with the use
of xdr_stream helpers that are used most everywhere else XDR
decoding is done.

One minor change to the sanity checks: instead of checking the
length of individual segments, cap the length of the whole chunk
to be sure it can fit in the set of pages available in rq_pages.
This should be a better test of whether the server can handle the
chunks in each request.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Clean up. This trace point is no longer needed because the RDMA/core
CMA code has an equivalent trace point that was added by commit
ed999f82 ("RDMA/cma: Add trace points in RDMA Connection
Manager").
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

This class can be used to create trace points in either the RPC
client or RPC server paths. It simply displays the length of each
part of an xdr_buf, which is useful to determine that the transport
and XDR codecs are operating correctly.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Introduce a helper function to compute the XDR pad size of a
variable-length XDR object.

Clean up: Replace open-coded calculation of XDR pad sizes.
I'm sure I haven't found every instance of this calculation.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

This error path is almost never executed. Found by code inspection.

Fixes: 99722fe4 ("svcrdma: Persistently allocate and DMA-map Send buffers")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Address some minor nits I noticed while working on this function.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

svcrdma expects that the payload falls precisely into the xdr_buf
page vector. This does not seem to be the case for
nfsd4_encode_readv().

This code is called only when fops->splice_read is missing or when
RQ_SPLICE_OK is clear, so it's not a noticeable problem in many
common cases.

Add new transport method: ->xpo_read_payload so that when a READ
payload does not fit exactly in rq_res's page vector, the XDR
encoder can inform the RPC transport exactly where that payload is,
without the payload's XDR pad.

That way, when a Write chunk is present, the transport knows what
byte range in the Reply message is supposed to be matched with the
chunk.

Note that the Linux NFS server implementation of NFS/RDMA can
currently handle only one Write chunk per RPC-over-RDMA message.
This simplifies the implementation of this fix.

Fixes: b0420980 ("nfsd4: allow exotic read compounds")
Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=198053Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

list_for_each_entry_rcu() has built-in RCU and lock checking.

Pass cond argument to list_for_each_entry_rcu() to silence
false lockdep warning when  CONFIG_PROVE_RCU_LIST is enabled
by default.
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

list_for_each_entry_rcu() has built-in RCU and lock checking.

Pass cond argument to list_for_each_entry_rcu() to silence
false lockdep warning when  CONFIG_PROVE_RCU_LIST is enabled
by default.
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

detail->hash_table[] is traversed using hlist_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of detail->hash_lock.

Hence, add corresponding lockdep expression to silence false-positive
warnings, and harden RCU lists.
Signed-off-by: Amol Grover <frextrite@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Currently, nfsd4_encode_exchange_id() encodes the utsname nodename
string in the server_scope field.  In a multi-host container
environemnt, if an nfsd container is restarted on a different host than
it was originally running on, clients will see a server_scope mismatch
and will not attempt to reclaim opens.

Instead, set the server_scope while we're in a process context during
service startup, so we get the utsname nodename of the current process
and store that in nfsd_net.
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
[bfields: fix up major_id too]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.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