When enabling many VFs and switching to switchdev mode, the total amount
of mkeys we try to allocate when loading representors is very large and
may cause timeouts on allocations, the same issues was observed on VFs
and we employ the same fix that was done for them. We avoid allocating
the full MR cache on load but still allow it to be manipulated once the
IB device is loaded.
Signed-off-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Currently in switchdev mode we allow only for raw packet QPs.
Expose the right capabilities and set the gid table length to 0, also
make sure we don't try to enable RoCE, so split the function
to enable RoCE so representors can enable only the notifier needed for
net device events.
Signed-off-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Currently we listen to netdev register/unregister event based on PCI
device. When in switchdev mode PF and representors share the same PCI
device, so in order to pair ib device and netdev in switchdev mode
compare the netdev that triggered the event to that of the representor.

Expose a function that lets you receive the netdev associated what
a given representor.
Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

When we point to a representor, it means we are in switchdev mode.
The flow db is shared between PF and virtual function representors
so each rule created needs to have a match on its specific source port.
Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

A flow DB is a shared resource between PF and representors,
need to allocate it only when creating the PF IB device.
Once we add IB representors, they will use the flow db which was
created by the PF.
Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Create the basic infrastructure of registering and unregistering
IB representors. The load/unload callbacks are left empty and
proper implementation will be introduced in following patches.
Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Create a new representor type: REP_IB. which will be initialized by an IB
device that is used as a logical representor of a eswitch vport (VF or
uplink) just like we have a net device today in switchdev mode.
Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Under switchdev mode we insert an eswitch miss rule causing any
unmatched traffic to be sent towards the PF vport. This miss rule can
be optimized if we break it to two, one case is for multicast traffic and
the other for unicast.

Breaking the miss rule into two (unicast and multicast) allows the firmware
to program the hardware in a more efficient way.

Using ConncetX-5 Ex with IXIA and testpmd (which use IB representors):

IXIA -> NIC -> PF -> IB representor -> NIC -> VF:
    - Without this optimization: 9.2 MPPS.
    - With this optimization: 18 MPPS.

VF -> NIC -> IB representor-> PF -> NIC -> IXIA:
    - Without this optimization: 17 MPPS.
    - With this optimization: 23.4 MPPS.
Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

The max FTE number should be the max number of SQs that can be opened.
Ethernet representors open one SQ each. Once we add IB representor this
will increase (depends on the user). For now lets start with 31
per IB representor and if needed increase in the future.

This increase only affects the number of FTEs in the slow path FDB,
offloaded rules (done via TC on the fast path portion of the FDB)
aren't affected.
Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

In preparation for IB representors, move representors structs to a global
scope, also expose functions needed for registration, unregistration,
eswitch mode and creating a flow rule to direct traffic from SQs to the
right VF.
Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Add a callback interface to get a protocol device (per representor type).
The Ethernet representors will expose their netdev via this interface.

This functionality can be later used by IB representor in order to find the
corresponding net device representor.
Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

The current implementation of create CQ requires contiguous
memory, such requirement is problematic once the memory is
fragmented or the system is low in memory, it causes for
failures in dma_zalloc_coherent().

This patch implements new scheme of fragmented CQ to overcome
this issue by introducing new type: 'struct mlx5_frag_buf_ctrl'
to allocate fragmented buffers, rather than contiguous ones.

Base the Completion Queues (CQs) on this new fragmented buffer.

It fixes following crashes:
kworker/29:0: page allocation failure: order:6, mode:0x80d0
CPU: 29 PID: 8374 Comm: kworker/29:0 Tainted: G OE 3.10.0
Workqueue: ib_cm cm_work_handler [ib_cm]
Call Trace:
[<>] dump_stack+0x19/0x1b
[<>] warn_alloc_failed+0x110/0x180
[<>] __alloc_pages_slowpath+0x6b7/0x725
[<>] __alloc_pages_nodemask+0x405/0x420
[<>] dma_generic_alloc_coherent+0x8f/0x140
[<>] x86_swiotlb_alloc_coherent+0x21/0x50
[<>] mlx5_dma_zalloc_coherent_node+0xad/0x110 [mlx5_core]
[<>] ? mlx5_db_alloc_node+0x69/0x1b0 [mlx5_core]
[<>] mlx5_buf_alloc_node+0x3e/0xa0 [mlx5_core]
[<>] mlx5_buf_alloc+0x14/0x20 [mlx5_core]
[<>] create_cq_kernel+0x90/0x1f0 [mlx5_ib]
[<>] mlx5_ib_create_cq+0x3b0/0x4e0 [mlx5_ib]
Signed-off-by: Yonatan Cohen <yonatanc@mellanox.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

EQ structure and API is private to mlx5_core driver only, external
drivers should not have access or the means to manipulate EQ objects.

Remove redundant exports and move API functions out of the linux/mlx5
include directory into the driver's mlx5_core.h private include file.
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reviewed-by: Gal Pressman <galp@mellanox.com>

Since CQ tree is now per EQ, CQ completion and event forwarding became
specific implementation of EQ logic, this patch moves that logic to eq.c
and makes those functions static.
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reviewed-by: Gal Pressman <galp@mellanox.com>

Now as the CQ table is per EQ, add an API to hold/put CQ to be used from
eq.c in downstream patch.
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reviewed-by: Gal Pressman <galp@mellanox.com>

Add API to add/del CQ to/from EQs CQ table to be used in cq.c upon CQ
creation/destruction, as CQ table is now private to eq.c.
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reviewed-by: Gal Pressman <galp@mellanox.com>

If a hardware event is targeting a CQ, that CQ should exist.
Add unlikely to error handling flows.
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reviewed-by: Gal Pressman <galp@mellanox.com>

Before this patch the driver had one CQ database protected via one
spinlock, this spinlock is meant to synchronize between CQ
adding/removing and CQ IRQ interrupt handling.

On a system with large number of CPUs and on a work load that requires
lots of interrupts, this global spinlock becomes a very nasty hotspot
and introduces a contention between the active cores, which will
significantly hurt performance and becomes a bottleneck that prevents
seamless cpu scaling.

To solve this we simply move the CQ database and its spinlock to be per
EQ (IRQ), thus per core.

Tested with:
system: 2 sockets, 14 cores per socket, hyperthreading, 2x14x2=56 cores
netperf command: ./super_netperf 200 -P 0 -t TCP_RR  -H <server> -l 30 -- -r 300,300 -o -s 1M,1M -S 1M,1M

WITHOUT THIS PATCH:
Average:     CPU    %usr   %nice    %sys %iowait    %irq   %soft %steal  %guest  %gnice   %idle
Average:     all    4.32    0.00   36.15    0.09    0.00   34.02   0.00    0.00    0.00   25.41

Samples: 2M of event 'cycles:pp', Event count (approx.): 1554616897271
Overhead  Command          Shared Object                 Symbol
+   14.28%  swapper          [kernel.vmlinux]              [k] intel_idle
+   12.25%  swapper          [kernel.vmlinux]              [k] queued_spin_lock_slowpath
+   10.29%  netserver        [kernel.vmlinux]              [k] queued_spin_lock_slowpath
+    1.32%  netserver        [kernel.vmlinux]              [k] mlx5e_xmit

WITH THIS PATCH:
Average:     CPU    %usr   %nice    %sys %iowait    %irq   %soft  %steal  %guest  %gnice   %idle
Average:     all    4.27    0.00   34.31    0.01    0.00   18.71    0.00    0.00    0.00   42.69

Samples: 2M of event 'cycles:pp', Event count (approx.): 1498132937483
Overhead  Command          Shared Object             Symbol
+   23.33%  swapper          [kernel.vmlinux]          [k] intel_idle
+    1.69%  netserver        [kernel.vmlinux]          [k] mlx5e_xmit
Tested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reviewed-by: Gal Pressman <galp@mellanox.com>

except, again, POLLFREE and POLL_BUSY_LOOP.

With this, we finally get to the promised end result:

 - POLL{IN,OUT,...} are plain integers and *not* in __poll_t, so any
   stray instances of ->poll() still using those will be caught by
   sparse.

 - eventpoll.c and select.c warning-free wrt __poll_t

 - no more kernel-side definitions of POLL... - userland ones are
   visible through the entire kernel (and used pretty much only for
   mangle/demangle)

 - same behavior as after the first series (i.e. sparc et.al. epoll(2)
   working correctly).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.
Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull more poll annotation updates from Al Viro:
 "This is preparation to solving the problems you've mentioned in the
  original poll series.

  After this series, the kernel is ready for running

      for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
            L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
            for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
      done

  as a for bulk search-and-replace.

  After that, the kernel is ready to apply the patch to unify
  {de,}mangle_poll(), and then get rid of kernel-side POLL... uses
  entirely, and we should be all done with that stuff.

  Basically, that's what you suggested wrt KPOLL..., except that we can
  use EPOLL... instead - they already are arch-independent (and equal to
  what is currently kernel-side POLL...).

  After the preparations (in this series) switch to returning EPOLL...
  from ->poll() instances is completely mechanical and kernel-side
  POLL... can go away. The last step (killing kernel-side POLL... and
  unifying {de,}mangle_poll() has to be done after the
  search-and-replace job, since we need userland-side POLL... for
  unified {de,}mangle_poll(), thus the cherry-pick at the last step.

  After that we will have:

   - POLL{IN,OUT,...} *not* in __poll_t, so any stray instances of
     ->poll() still using those will be caught by sparse.

   - eventpoll.c and select.c warning-free wrt __poll_t

   - no more kernel-side definitions of POLL... - userland ones are
     visible through the entire kernel (and used pretty much only for
     mangle/demangle)

   - same behavior as after the first series (i.e. sparc et.al. epoll(2)
     working correctly)"

* 'work.poll2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  annotate ep_scan_ready_list()
  ep_send_events_proc(): return result via esed->res
  preparation to switching ->poll() to returning EPOLL...
  add EPOLLNVAL, annotate EPOLL... and event_poll->event
  use linux/poll.h instead of asm/poll.h
  xen: fix poll misannotation
  smc: missing poll annotations

Pull xtense fix from Max Filippov:
 "Build fix for xtensa architecture with KASAN enabled"

* tag 'xtensa-20180211' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: fix build with KASAN

Pull nios2 update from Ley Foon Tan:

 - clean up old Kconfig options from defconfig

 - remove leading 0x and 0s from bindings notation in dts files

* tag 'nios2-v4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/lftan/nios2:
  nios2: defconfig: Cleanup from old Kconfig options
  nios2: dts: Remove leading 0x and 0s from bindings notation

The commit 917538e2 ("kasan: clean up KASAN_SHADOW_SCALE_SHIFT
usage") removed KASAN_SHADOW_SCALE_SHIFT definition from
include/linux/kasan.h and added it to architecture-specific headers,
except for xtensa. This broke the xtensa build with KASAN enabled.
Define KASAN_SHADOW_SCALE_SHIFT in arch/xtensa/include/asm/kasan.h

Reported by: kbuild test robot <fengguang.wu@intel.com>
Fixes: 917538e2 ("kasan: clean up KASAN_SHADOW_SCALE_SHIFT usage")
Acked-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Remove old, dead Kconfig option INET_LRO. It is gone since
commit 7bbf3cae ("ipv4: Remove inet_lro library").
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Ley Foon Tan <ley.foon.tan@intel.com>

Improve the DTS files by removing all the leading "0x" and zeros to fix the
following dtc warnings:

Warning (unit_address_format): Node /XXX unit name should not have leading "0x"

and

Warning (unit_address_format): Node /XXX unit name should not have leading 0s

Converted using the following command:

find . -type f \( -iname *.dts -o -iname *.dtsi \) -exec sed -E -i -e "s/@0x([0-9a-fA-F\.]+)\s?\{/@\L\1 \{/g" -e "s/@0+([0-9a-fA-F\.]+)\s?\{/@\L\1 \{/g" {} +

For simplicity, two sed expressions were used to solve each warnings separately.

To make the regex expression more robust a few other issues were resolved,
namely setting unit-address to lower case, and adding a whitespace before the
the opening curly brace:

https://elinux.org/Device_Tree_Linux#Linux_conventions

This is a follow up to commit 4c9847b7 ("dt-bindings: Remove leading 0x from bindings notation")
Reported-by: David Daney <ddaney@caviumnetworks.com>
Suggested-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Acked-by: Ley Foon Tan <ley.foon.tan@intel.com>

Pull PCI fix from Bjorn Helgaas:
 "Fix a POWER9/powernv INTx regression from the merge window (Alexey
  Kardashevskiy)"

* tag 'pci-v4.16-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  powerpc/pci: Fix broken INTx configuration via OF

Pull block fixes from Jens Axboe:
 "A few fixes to round off the merge window on the block side:

   - a set of bcache fixes by way of Michael Lyle, from the usual bcache
     suspects.

   - add a simple-to-hook-into function for bpf EIO error injection.

   - fix blk-wbt that mischarectized flushes as reads. Improve the logic
     so that flushes and writes are accounted as writes, and only reads
     as reads. From me.

   - fix requeue crash in BFQ, from Paolo"

* tag 'for-linus-20180210' of git://git.kernel.dk/linux-block:
  block, bfq: add requeue-request hook
  bcache: fix for data collapse after re-attaching an attached device
  bcache: return attach error when no cache set exist
  bcache: set writeback_rate_update_seconds in range [1, 60] seconds
  bcache: fix for allocator and register thread race
  bcache: set error_limit correctly
  bcache: properly set task state in bch_writeback_thread()
  bcache: fix high CPU occupancy during journal
  bcache: add journal statistic
  block: Add should_fail_bio() for bpf error injection
  blk-wbt: account flush requests correctly

Pull x86 platform driver updates from Darren Hart:
 "Mellanox fixes and new system type support.

  Mostly data for new system types with a correction and an
  uninitialized variable fix"

[ Pulling from github because git.infradead.org currently seems to be
  down for some reason, but Darren had a backup location    - Linus ]

* tag 'platform-drivers-x86-v4.16-3' of git://github.com/dvhart/linux-pdx86:
  platform/x86: mlx-platform: Add support for new 200G IB and Ethernet systems
  platform/x86: mlx-platform: Add support for new msn201x system type
  platform/x86: mlx-platform: Add support for new msn274x system type
  platform/x86: mlx-platform: Fix power cable setting for msn21xx family
  platform/x86: mlx-platform: Add define for the negative bus
  platform/x86: mlx-platform: Use defines for bus assignment
  platform/mellanox: mlxreg-hotplug: Fix uninitialized variable

Merge tag 'chrome-platform-for-linus-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bleung/chrome-platform

Pull chrome platform updates from Benson Leung:

 - move cros_ec_dev to drivers/mfd

 - other small maintenance fixes

[ The cros_ec_dev movement came in earlier through the MFD tree  - Linus ]

* tag 'chrome-platform-for-linus-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bleung/chrome-platform:
  platform/chrome: Use proper protocol transfer function
  platform/chrome: cros_ec_lpc: Add support for Google Glimmer
  platform/chrome: cros_ec_lpc: Register the driver if ACPI entry is missing.
  platform/chrome: cros_ec_lpc: remove redundant pointer request
  cros_ec: fix nul-termination for firmware build info
  platform/chrome: chromeos_laptop: make chromeos_laptop const

Pull KVM updates from Radim Krčmář:
 "ARM:

   - icache invalidation optimizations, improving VM startup time

   - support for forwarded level-triggered interrupts, improving
     performance for timers and passthrough platform devices

   - a small fix for power-management notifiers, and some cosmetic
     changes

  PPC:

   - add MMIO emulation for vector loads and stores

   - allow HPT guests to run on a radix host on POWER9 v2.2 CPUs without
     requiring the complex thread synchronization of older CPU versions

   - improve the handling of escalation interrupts with the XIVE
     interrupt controller

   - support decrement register migration

   - various cleanups and bugfixes.

  s390:

   - Cornelia Huck passed maintainership to Janosch Frank

   - exitless interrupts for emulated devices

   - cleanup of cpuflag handling

   - kvm_stat counter improvements

   - VSIE improvements

   - mm cleanup

  x86:

   - hypervisor part of SEV

   - UMIP, RDPID, and MSR_SMI_COUNT emulation

   - paravirtualized TLB shootdown using the new KVM_VCPU_PREEMPTED bit

   - allow guests to see TOPOEXT, GFNI, VAES, VPCLMULQDQ, and more
     AVX512 features

   - show vcpu id in its anonymous inode name

   - many fixes and cleanups

   - per-VCPU MSR bitmaps (already merged through x86/pti branch)

   - stable KVM clock when nesting on Hyper-V (merged through
     x86/hyperv)"

* tag 'kvm-4.16-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (197 commits)
  KVM: PPC: Book3S: Add MMIO emulation for VMX instructions
  KVM: PPC: Book3S HV: Branch inside feature section
  KVM: PPC: Book3S HV: Make HPT resizing work on POWER9
  KVM: PPC: Book3S HV: Fix handling of secondary HPTEG in HPT resizing code
  KVM: PPC: Book3S PR: Fix broken select due to misspelling
  KVM: x86: don't forget vcpu_put() in kvm_arch_vcpu_ioctl_set_sregs()
  KVM: PPC: Book3S PR: Fix svcpu copying with preemption enabled
  KVM: PPC: Book3S HV: Drop locks before reading guest memory
  kvm: x86: remove efer_reload entry in kvm_vcpu_stat
  KVM: x86: AMD Processor Topology Information
  x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when running nested
  kvm: embed vcpu id to dentry of vcpu anon inode
  kvm: Map PFN-type memory regions as writable (if possible)
  x86/kvm: Make it compile on 32bit and with HYPYERVISOR_GUEST=n
  KVM: arm/arm64: Fixup userspace irqchip static key optimization
  KVM: arm/arm64: Fix userspace_irqchip_in_use counting
  KVM: arm/arm64: Fix incorrect timer_is_pending logic
  MAINTAINERS: update KVM/s390 maintainers
  MAINTAINERS: add Halil as additional vfio-ccw maintainer
  MAINTAINERS: add David as a reviewer for KVM/s390
  ...

59f47eff ("powerpc/pci: Use of_irq_parse_and_map_pci() helper")
replaced of_irq_parse_pci() + irq_create_of_mapping() with
of_irq_parse_and_map_pci(), but neglected to capture the virq
returned by irq_create_of_mapping(), so virq remained zero, which
caused INTx configuration to fail.

Save the virq value returned by of_irq_parse_and_map_pci() and correct
the virq declaration to match the of_irq_parse_and_map_pci() signature.

Fixes: 59f47eff "powerpc/pci: Use of_irq_parse_and_map_pci() helper"
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Pull more Kbuild updates from Masahiro Yamada:
 "Makefile changes:
   - enable unused-variable warning that was wrongly disabled for clang

  Kconfig changes:
   - warn about blank 'help' and fix existing instances
   - fix 'choice' behavior to not write out invisible symbols
   - fix misc weirdness

  Coccinell changes:
   - fix false positive of free after managed memory alloc detection
   - improve performance of NULL dereference detection"

* tag 'kbuild-v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (21 commits)
  kconfig: remove const qualifier from sym_expand_string_value()
  kconfig: add xrealloc() helper
  kconfig: send error messages to stderr
  kconfig: echo stdin to stdout if either is redirected
  kconfig: remove check_stdin()
  kconfig: remove 'config*' pattern from .gitignnore
  kconfig: show '?' prompt even if no help text is available
  kconfig: do not write choice values when their dependency becomes n
  coccinelle: deref_null: avoid useless computation
  coccinelle: devm_free: reduce false positives
  kbuild: clang: disable unused variable warnings only when constant
  kconfig: Warn if help text is blank
  nios2: kconfig: Remove blank help text
  arm: vt8500: kconfig: Remove blank help text
  MIPS: kconfig: Remove blank help text
  MIPS: BCM63XX: kconfig: Remove blank help text
  lib/Kconfig.debug: Remove blank help text
  Staging: rtl8192e: kconfig: Remove blank help text
  Staging: rtl8192u: kconfig: Remove blank help text
  mmc: kconfig: Remove blank help text
  ...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull misc vfs fixes from Al Viro.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  seq_file: fix incomplete reset on read from zero offset
  kernfs: fix regression in kernfs_fop_write caused by wrong type

This function returns realloc'ed memory, so the returned pointer
must be passed to free() when done.  So, 'const' qualifier is odd.
It is allowed to modify the expanded string.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

We already have xmalloc(), xcalloc().  Add xrealloc() as well
to save tedious error handling.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

It adds support for new Mellanox system types of basic classes qmb7, sn34,
sn37, containing systems QMB700 (40x200GbE InfiniBand switch), SN3700
(32x200GbE and 16x400GbE Ethernet switch) and SN3410 (6x400GbE plus
48x50GbE Ethernet switch). These are the Top of the Rack systems, equipped
with Mellanox COM-Express carrier board and switch board with Mellanox
Quantum device, which supports InfiniBand switching with 40X200G ports and
line rate of up to HDR speed or with Mellanox Spectrum-2 device, which
supports Ethernet switching with 32X200G ports line rate of up to HDR
speed.
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

It adds support for new Mellanox system types of basic half unit size
class msn201x, containing system MSN2010 (18x10GbE plus 4x4x25GbE) half
and its derivatives. This is the Top of the Rack system, equipped with
Mellanox Small Form Factor carrier board and switch board with Mellanox
Spectrum device, which supports Ethernet switching with 32X100G ports line
rate of up to EDR speed.
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>