raid6: guard the tables.c include of <linux/export.h> with __KERNEL__

The export directives for the tables are already emitted with __KERNEL__
guards, but the <linux/export.h> include is not, causing errors when
building the raid6test program. Guard this include too to fix the
raid6test build.

Signed-off-by: WANG Xuerui <git@xen0n.name>
Link: https://lore.kernel.org/r/20230731104911.411964-3-kernel@xen0n.name
Signed-off-by: Song Liu <song@kernel.org>

raid6/test: fix a compilation warning

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>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 83

Based on 1 normalized pattern(s):

this file is part of the linux kernel and is made available under
the terms of the gnu general public license version 2 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 18 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520075211.321157221@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

lib/raid6: Add log-of-2 table for RAID6 HW requiring disk position

The raid6_gfexp table represents {2}^n values for 0 <= n < 256. The
Linux async_tx framework pass values from raid6_gfexp as coefficients
for each source to prep_dma_pq() callback of DMA channel with PQ
capability. This creates problem for RAID6 offload engines (such as
Broadcom SBA) which take disk position (i.e. log of {2}) instead of
multiplicative cofficients from raid6_gfexp table.

This patch adds raid6_gflog table having log-of-2 value for any given
x such that 0 <= x < 256. For any given disk coefficient x, the
corresponding disk position is given by raid6_gflog[x]. The RAID6
offload engine driver can use this newly added raid6_gflog table to
get disk position from multiplicative coefficient.

Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Acked-by: Shaohua Li <shli@fb.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

lib/raid6: Add SSSE3 optimized recovery functions

Add SSSE3 optimized recovery functions, as well as a system
for selecting the most appropriate recovery functions to use.

Originally-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Jim Kukunas <james.t.kukunas@linux.intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>

md: Add in export.h for files using EXPORT_SYMBOL

These files were getting the defines for EXPORT_SYMBOL because
device.h was including module.h. But we are going to put an
end to that. So add the proper export.h include now.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

md: Factor out RAID6 algorithms into lib/

We'll want to use these in btrfs too.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>