RAID6_USE_EMPTY_ZERO_PAGE is unused and hardcoded to 0, so let's drop it.

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>

On x86_64, currently 3 variants of AVX512, 3 variants of AVX2
and 3 variants of SSE2 are benchmarked on initialization, taking
between 144-153 jiffies. Testing across a hardware pool of
various generations of intel cpus I could not find a single
case where SSE2 won over AVX2 or AVX512. There are cases where
AVX2 wins over AVX512 however.

Change "prefer" into an integer priority field (similar to
how recov selection works) to have more than one ranking level
available, which is backwards compatible with existing behavior.

Give AVX2/512 variants higher priority over SSE2 in order to skip
SSE testing when AVX is available. in a AVX2/x86_64/HZ=250 case this
saves in the order of 200ms of initialization time.

Signed-off-by: Dirk Müller <dmueller@suse.de>
Acked-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Song Liu <song@kernel.org>

There are several algorithms available for raid6 to generate xor and syndrome
parity, including basic int1, int2 ... int32 and SIMD optimized implementation
like sse and neon.  To test and choose the best algorithms at the initial
stage, we need provide enough disk data to feed the algorithms. However, the
disk number we provided depends on page size and gfmul table, seeing bellow:

    const int disks = (65536/PAGE_SIZE) + 2;

So when come to 64K PAGE_SIZE, there is only one data disk plus 2 parity disk,
as a result the chosed algorithm is not reliable. For example, on my arm64
machine with 64K page enabled, it will choose intx32 as the best one, although
the NEON implementation is better.

This patch tries to fix the problem by defining a constant raid6 disk number to
supporting arbitrary page size.

Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Zhengyuan Liu <liuzhengyuan@kylinos.cn>
Signed-off-by: Song Liu <songliubraving@fb.com>

The compilation warning is redefination showed as following:

        In file included from tables.c:2:
        ../../../include/linux/export.h:180: warning: "EXPORT_SYMBOL" redefined
         #define EXPORT_SYMBOL(sym)  __EXPORT_SYMBOL(sym, "")

        In file included from tables.c:1:
        ../../../include/linux/raid/pq.h:61: note: this is the location of the previous definition
         #define EXPORT_SYMBOL(sym)

Fixes: 69a94abb82ee ("export.h, genksyms: do not make genksyms calculate CRC of trimmed symbols")
Signed-off-by: Zhengyuan Liu <liuzhengyuan@kylinos.cn>
Signed-off-by: Song Liu <songliubraving@fb.com>

The compilation error is redeclaration showed as following:

        In file included from ../../../include/linux/limits.h:6,
                         from /usr/include/x86_64-linux-gnu/bits/local_lim.h:38,
                         from /usr/include/x86_64-linux-gnu/bits/posix1_lim.h:161,
                         from /usr/include/limits.h:183,
                         from /usr/lib/gcc/x86_64-linux-gnu/8/include-fixed/limits.h:194,
                         from /usr/lib/gcc/x86_64-linux-gnu/8/include-fixed/syslimits.h:7,
                         from /usr/lib/gcc/x86_64-linux-gnu/8/include-fixed/limits.h:34,
                         from ../../../include/linux/raid/pq.h:30,
                         from algos.c:14:
        ../../../include/linux/types.h:114:15: error: conflicting types for ‘int64_t’
         typedef s64   int64_t;
                       ^~~~~~~
        In file included from /usr/include/stdint.h:34,
                         from /usr/lib/gcc/x86_64-linux-gnu/8/include/stdint.h:9,
                         from /usr/include/inttypes.h:27,
                         from ../../../include/linux/raid/pq.h:29,
                         from algos.c:14:
        /usr/include/x86_64-linux-gnu/bits/stdint-intn.h:27:19: note: previous \
        declaration of ‘int64_t’ was here
         typedef __int64_t int64_t;

Fixes: 54d50897d544 ("linux/kernel.h: split *_MAX and *_MIN macros into <linux/limits.h>")
Signed-off-by: Zhengyuan Liu <liuzhengyuan@kylinos.cn>
Signed-off-by: Song Liu <songliubraving@fb.com>

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation inc 53 temple place ste 330 boston ma
  02111 1307 usa either version 2 of the license or at your option any
  later version incorporated herein by reference

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 13 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170858.645641371@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This is helpful for systems where fast startup time is important.
It is especially nice to avoid benchmarking RAID functions that are
never used (for example, BTRFS selects RAID6_PQ even if the parity RAID
mode is not in use).

This saves 250+ milliseconds of boot time on modern x86 and ARM systems
with a dozen or more available implementations.

The new option is defaulted to 'y' to match the previous behavior of
always benchmarking on init.

Signed-off-by: Daniel Verkamp <dverkamp@chromium.org>
Signed-off-by: Shaohua Li <shli@fb.com>

This is defined in glibc's sys/cdefs.h on my system with the same
definition as the raid6test fallback definition.  Add a #ifndef check to
avoid a compiler warning about redefining it.

Signed-off-by: Daniel Verkamp <dverkamp@chromium.org>
Signed-off-by: Shaohua Li <shli@fb.com>

Add #include <sys/time.h> for gettimeofday() to fix the compiler warning
about an implicitly defined functions.

Signed-off-by: Daniel Verkamp <dverkamp@chromium.org>
Signed-off-by: Shaohua Li <shli@fb.com>

Pull powerpc updates from Michael Ellerman:
 "Notable changes:

   - Support for 4PB user address space on 64-bit, opt-in via mmap().

   - Removal of POWER4 support, which was accidentally broken in 2016
     and no one noticed, and blocked use of some modern instructions.

   - Workarounds so that the hypervisor can enable Transactional Memory
     on Power9.

   - A series to disable the DAWR (Data Address Watchpoint Register) on
     Power9.

   - More information displayed in the meltdown/spectre_v1/v2 sysfs
     files.

   - A vpermxor (Power8 Altivec) implementation for the raid6 Q
     Syndrome.

   - A big series to make the allocation of our pacas (per cpu area),
     kernel page tables, and per-cpu stacks NUMA aware when using the
     Radix MMU on Power9.

  And as usual many fixes, reworks and cleanups.

  Thanks to: Aaro Koskinen, Alexandre Belloni, Alexey Kardashevskiy,
  Alistair Popple, Andy Shevchenko, Aneesh Kumar K.V, Anshuman Khandual,
  Balbir Singh, Benjamin Herrenschmidt, Christophe Leroy, Christophe
  Lombard, Cyril Bur, Daniel Axtens, Dave Young, Finn Thain, Frederic
  Barrat, Gustavo Romero, Horia Geantă, Jonathan Neuschäfer, Kees Cook,
  Larry Finger, Laurent Dufour, Laurent Vivier, Logan Gunthorpe,
  Madhavan Srinivasan, Mark Greer, Mark Hairgrove, Markus Elfring,
  Mathieu Malaterre, Matt Brown, Matt Evans, Mauricio Faria de Oliveira,
  Michael Neuling, Naveen N. Rao, Nicholas Piggin, Paul Mackerras,
  Philippe Bergheaud, Ram Pai, Rob Herring, Sam Bobroff, Segher
  Boessenkool, Simon Guo, Simon Horman, Stewart Smith, Sukadev
  Bhattiprolu, Suraj Jitindar Singh, Thiago Jung Bauermann, Vaibhav
  Jain, Vaidyanathan Srinivasan, Vasant Hegde, Wei Yongjun"

* tag 'powerpc-4.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (207 commits)
  powerpc/64s/idle: Fix restore of AMOR on POWER9 after deep sleep
  powerpc/64s: Fix POWER9 DD2.2 and above in cputable features
  powerpc/64s: Fix pkey support in dt_cpu_ftrs, add CPU_FTR_PKEY bit
  powerpc/64s: Fix dt_cpu_ftrs to have restore_cpu clear unwanted LPCR bits
  Revert "powerpc/64s/idle: POWER9 ESL=0 stop avoid save/restore overhead"
  powerpc: iomap.c: introduce io{read|write}64_{lo_hi|hi_lo}
  powerpc: io.h: move iomap.h include so that it can use readq/writeq defs
  cxl: Fix possible deadlock when processing page faults from cxllib
  powerpc/hw_breakpoint: Only disable hw breakpoint if cpu supports it
  powerpc/mm/radix: Update command line parsing for disable_radix
  powerpc/mm/radix: Parse disable_radix commandline correctly.
  powerpc/mm/hugetlb: initialize the pagetable cache correctly for hugetlb
  powerpc/mm/radix: Update pte fragment count from 16 to 256 on radix
  powerpc/mm/keys: Update documentation and remove unnecessary check
  powerpc/64s/idle: POWER9 ESL=0 stop avoid save/restore overhead
  powerpc/64s/idle: Consolidate power9_offline_stop()/power9_idle_stop()
  powerpc/powernv: Always stop secondaries before reboot/shutdown
  powerpc: hard disable irqs in smp_send_stop loop
  powerpc: use NMI IPI for smp_send_stop
  powerpc/powernv: Fix SMT4 forcing idle code
  ...