raid6: turn the userspace test harness into a kunit test

Patch series "cleanup the RAID6 P/Q library", v3.

This series cleans up the RAID6 P/Q library to match the recent updates to
the RAID 5 XOR library and other CRC/crypto libraries.  This includes
providing properly documented external interfaces, hiding the internals,
using static_call instead of indirect calls and turning the user space
test suite into an in-kernel kunit test which is also extended to improve
coverage.

Note that this changes registration so that non-priority algorithms are
not registered, which greatly helps with the benchmark time at boot time. 
I'd like to encourage all architecture maintainers to see if they can
further optimized this by registering as few as possible algorithms when
there is a clear benefit in optimized or more unrolled implementations.


This patch (of 18):

Currently the raid6 code can be compiled as userspace code to run the test
suite.  Convert that to be a kunit case with minimal changes to avoid
mutating global state so that we can drop this requirement.

Note that this is not a good kunit test case yet and will need a lot more
work, but that is deferred until the raid6 code is moved to it's new
place, which is easier if the userspace makefile doesn't need adjustments
for the new location first.

Link: https://lore.kernel.org/20260518051804.462141-1-hch@lst.de
Link: https://lore.kernel.org/20260518051804.462141-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Li Nan <linan122@huawei.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Song Liu <song@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 85 insertions, 228 deletions

diff --git a/lib/raid6/test/Makefile b/lib/raid6/test/Makefile
index 09bbe2b14cce..520381ea71d7 100644
--- a/lib/raid6/test/Makefile
+++ b/lib/raid6/test/Makefile
@@ -1,156 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
-#
-# This is a simple Makefile to test some of the RAID-6 code
-# from userspace.
-#
 
-pound := \#
+obj-$(CONFIG_RAID6_PQ_KUNIT_TEST)	+= raid6_kunit.o
 
-# Adjust as desired
-CC       = gcc
-OPTFLAGS = -O2
-CFLAGS   = -I.. -I ../../../include -g $(OPTFLAGS)
-LD       = ld
-AWK      = awk -f
-AR       = ar
-RANLIB   = ranlib
-OBJS     = int1.o int2.o int4.o int8.o int16.o int32.o recov.o algos.o tables.o
-
-ARCH := $(shell uname -m 2>/dev/null | sed -e /s/i.86/i386/)
-ifeq ($(ARCH),i386)
-        CFLAGS += -DCONFIG_X86_32
-        IS_X86 = yes
-endif
-ifeq ($(ARCH),x86_64)
-        CFLAGS += -DCONFIG_X86_64
-        IS_X86 = yes
-endif
-
-ifeq ($(ARCH),arm)
-        CFLAGS += -I../../../arch/arm/include -mfpu=neon
-        HAS_NEON = yes
-endif
-ifeq ($(ARCH),aarch64)
-        CFLAGS += -I../../../arch/arm64/include
-        HAS_NEON = yes
-endif
-
-ifeq ($(findstring riscv,$(ARCH)),riscv)
-        CFLAGS += -I../../../arch/riscv/include -DCONFIG_RISCV=1
-        HAS_RVV = yes
-endif
-
-ifeq ($(findstring ppc,$(ARCH)),ppc)
-        CFLAGS += -I../../../arch/powerpc/include
-        HAS_ALTIVEC := $(shell printf '$(pound)include <altivec.h>\nvector int a;\n' |\
-                         gcc -c -x c - >/dev/null && rm ./-.o && echo yes)
-endif
-
-ifeq ($(ARCH),loongarch64)
-        CFLAGS += -I../../../arch/loongarch/include -DCONFIG_LOONGARCH=1
-        CFLAGS += $(shell echo 'vld $$vr0, $$zero, 0' |         \
-                    gcc -c -x assembler - >/dev/null 2>&1 &&    \
-                    rm ./-.o && echo -DCONFIG_CPU_HAS_LSX=1)
-        CFLAGS += $(shell echo 'xvld $$xr0, $$zero, 0' |        \
-                    gcc -c -x assembler - >/dev/null 2>&1 &&    \
-                    rm ./-.o && echo -DCONFIG_CPU_HAS_LASX=1)
-endif
-
-ifeq ($(IS_X86),yes)
-        OBJS   += mmx.o sse1.o sse2.o avx2.o recov_ssse3.o recov_avx2.o avx512.o recov_avx512.o
-        CFLAGS += -DCONFIG_X86
-else ifeq ($(HAS_NEON),yes)
-        OBJS   += neon.o neon1.o neon2.o neon4.o neon8.o recov_neon.o recov_neon_inner.o
-        CFLAGS += -DCONFIG_KERNEL_MODE_NEON=1
-else ifeq ($(HAS_ALTIVEC),yes)
-        CFLAGS += -DCONFIG_ALTIVEC
-        OBJS += altivec1.o altivec2.o altivec4.o altivec8.o \
-                vpermxor1.o vpermxor2.o vpermxor4.o vpermxor8.o
-else ifeq ($(ARCH),loongarch64)
-        OBJS += loongarch_simd.o recov_loongarch_simd.o
-else ifeq ($(HAS_RVV),yes)
-        OBJS   += rvv.o recov_rvv.o
-        CFLAGS += -DCONFIG_RISCV_ISA_V=1
-endif
-
-.c.o:
-	$(CC) $(CFLAGS) -c -o $@ $<
-
-%.c: ../%.c
-	cp -f $< $@
-
-%.uc: ../%.uc
-	cp -f $< $@
-
-all: raid6.a raid6test
-
-raid6.a: $(OBJS)
-	rm -f $@
-	$(AR) cq $@ $^
-	$(RANLIB) $@
-
-raid6test: test.c raid6.a
-	$(CC) $(CFLAGS) -o raid6test $^
-
-neon1.c: neon.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=1 < neon.uc > $@
-
-neon2.c: neon.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=2 < neon.uc > $@
-
-neon4.c: neon.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=4 < neon.uc > $@
-
-neon8.c: neon.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=8 < neon.uc > $@
-
-altivec1.c: altivec.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=1 < altivec.uc > $@
-
-altivec2.c: altivec.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=2 < altivec.uc > $@
-
-altivec4.c: altivec.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=4 < altivec.uc > $@
-
-altivec8.c: altivec.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=8 < altivec.uc > $@
-
-vpermxor1.c: vpermxor.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=1 < vpermxor.uc > $@
-
-vpermxor2.c: vpermxor.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=2 < vpermxor.uc > $@
-
-vpermxor4.c: vpermxor.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=4 < vpermxor.uc > $@
-
-vpermxor8.c: vpermxor.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=8 < vpermxor.uc > $@
-
-int1.c: int.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=1 < int.uc > $@
-
-int2.c: int.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=2 < int.uc > $@
-
-int4.c: int.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=4 < int.uc > $@
-
-int8.c: int.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=8 < int.uc > $@
-
-int16.c: int.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=16 < int.uc > $@
-
-int32.c: int.uc ../unroll.awk
-	$(AWK) ../unroll.awk -vN=32 < int.uc > $@
-
-tables.c: mktables
-	./mktables > tables.c
-
-clean:
-	rm -f *.o *.a mktables mktables.c *.uc int*.c altivec*.c vpermxor*.c neon*.c tables.c raid6test
-
-spotless: clean
-	rm -f *~
+raid6_kunit-y += test.o
diff --git a/lib/raid6/test/test.c b/lib/raid6/test/test.c
index 841a55242aba..9db287b4a48f 100644
--- a/lib/raid6/test/test.c
+++ b/lib/raid6/test/test.c
@@ -1,43 +1,37 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
-/* -*- linux-c -*- ------------------------------------------------------- *
- *
- *   Copyright 2002-2007 H. Peter Anvin - All Rights Reserved
- *
- * ----------------------------------------------------------------------- */
-
 /*
- * raid6test.c
+ * Copyright 2002-2007 H. Peter Anvin - All Rights Reserved
  *
- * Test RAID-6 recovery with various algorithms
+ * Test RAID-6 recovery algorithms.
  */
 
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
+#include <kunit/test.h>
+#include <linux/prandom.h>
 #include <linux/raid/pq.h>
 
-#define NDISKS		16	/* Including P and Q */
+MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
+
+#define RAID6_KUNIT_SEED		42
 
-const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
+#define NDISKS		16	/* Including P and Q */
 
-char *dataptrs[NDISKS];
-char data[NDISKS][PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
-char recovi[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
-char recovj[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
+static struct rnd_state rng;
+static void *dataptrs[NDISKS];
+static char data[NDISKS][PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
+static char recovi[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
+static char recovj[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
 
 static void makedata(int start, int stop)
 {
-	int i, j;
+	int i;
 
 	for (i = start; i <= stop; i++) {
-		for (j = 0; j < PAGE_SIZE; j++)
-			data[i][j] = rand();
-
+		prandom_bytes_state(&rng, data[i], PAGE_SIZE);
 		dataptrs[i] = data[i];
 	}
 }
 
-static char disk_type(int d)
+static char member_type(int d)
 {
 	switch (d) {
 	case NDISKS-2:
@@ -49,104 +43,118 @@ static char disk_type(int d)
 	}
 }
 
-static int test_disks(int i, int j)
+static void test_disks(struct kunit *test, const struct raid6_calls *calls,
+		const struct raid6_recov_calls *ra, int faila, int failb)
 {
-	int erra, errb;
-
 	memset(recovi, 0xf0, PAGE_SIZE);
 	memset(recovj, 0xba, PAGE_SIZE);
 
-	dataptrs[i] = recovi;
-	dataptrs[j] = recovj;
-
-	raid6_dual_recov(NDISKS, PAGE_SIZE, i, j, (void **)&dataptrs);
-
-	erra = memcmp(data[i], recovi, PAGE_SIZE);
-	errb = memcmp(data[j], recovj, PAGE_SIZE);
-
-	if (i < NDISKS-2 && j == NDISKS-1) {
-		/* We don't implement the DQ failure scenario, since it's
-		   equivalent to a RAID-5 failure (XOR, then recompute Q) */
-		erra = errb = 0;
+	dataptrs[faila] = recovi;
+	dataptrs[failb] = recovj;
+
+	if (failb == NDISKS - 1) {
+		/*
+		 * We don't implement the data+Q failure scenario, since it
+		 * is equivalent to a RAID-5 failure (XOR, then recompute Q).
+		 */
+		if (faila != NDISKS - 2)
+			goto skip;
+
+		/* P+Q failure.  Just rebuild the syndrome. */
+		calls->gen_syndrome(NDISKS, PAGE_SIZE, dataptrs);
+	} else if (failb == NDISKS - 2) {
+		/* data+P failure. */
+		ra->datap(NDISKS, PAGE_SIZE, faila, dataptrs);
 	} else {
-		printf("algo=%-8s  faila=%3d(%c)  failb=%3d(%c)  %s\n",
-		       raid6_call.name,
-		       i, disk_type(i),
-		       j, disk_type(j),
-		       (!erra && !errb) ? "OK" :
-		       !erra ? "ERRB" :
-		       !errb ? "ERRA" : "ERRAB");
+		/* data+data failure. */
+		ra->data2(NDISKS, PAGE_SIZE, faila, failb, dataptrs);
 	}
 
-	dataptrs[i] = data[i];
-	dataptrs[j] = data[j];
-
-	return erra || errb;
+	KUNIT_EXPECT_MEMEQ_MSG(test, data[faila], recovi, PAGE_SIZE,
+		"algo=%-8s/%-8s faila miscompared: %3d[%c] (failb=%3d[%c])\n",
+	       calls->name, ra->name,
+	       faila, member_type(faila),
+	       failb, member_type(failb));
+	KUNIT_EXPECT_MEMEQ_MSG(test, data[failb], recovj, PAGE_SIZE,
+		"algo=%-8s/%-8s failb miscompared: %3d[%c] (faila=%3d[%c])\n",
+	       calls->name, ra->name,
+	       failb, member_type(failb),
+	       faila, member_type(faila));
+
+skip:
+	dataptrs[faila] = data[faila];
+	dataptrs[failb] = data[failb];
 }
 
-int main(int argc, char *argv[])
+static void raid6_test(struct kunit *test)
 {
 	const struct raid6_calls *const *algo;
 	const struct raid6_recov_calls *const *ra;
 	int i, j, p1, p2;
-	int err = 0;
-
-	makedata(0, NDISKS-1);
 
 	for (ra = raid6_recov_algos; *ra; ra++) {
 		if ((*ra)->valid  && !(*ra)->valid())
 			continue;
 
-		raid6_2data_recov = (*ra)->data2;
-		raid6_datap_recov = (*ra)->datap;
-
-		printf("using recovery %s\n", (*ra)->name);
-
 		for (algo = raid6_algos; *algo; algo++) {
-			if ((*algo)->valid && !(*algo)->valid())
-				continue;
+			const struct raid6_calls *calls = *algo;
 
-			raid6_call = **algo;
+			if (calls->valid && !calls->valid())
+				continue;
 
 			/* Nuke syndromes */
-			memset(data[NDISKS-2], 0xee, 2*PAGE_SIZE);
+			memset(data[NDISKS - 2], 0xee, PAGE_SIZE);
+			memset(data[NDISKS - 1], 0xee, PAGE_SIZE);
 
 			/* Generate assumed good syndrome */
-			raid6_call.gen_syndrome(NDISKS, PAGE_SIZE,
+			calls->gen_syndrome(NDISKS, PAGE_SIZE,
 						(void **)&dataptrs);
 
 			for (i = 0; i < NDISKS-1; i++)
 				for (j = i+1; j < NDISKS; j++)
-					err += test_disks(i, j);
+					test_disks(test, calls, *ra, i, j);
 
-			if (!raid6_call.xor_syndrome)
+			if (!calls->xor_syndrome)
 				continue;
 
 			for (p1 = 0; p1 < NDISKS-2; p1++)
 				for (p2 = p1; p2 < NDISKS-2; p2++) {
 
 					/* Simulate rmw run */
-					raid6_call.xor_syndrome(NDISKS, p1, p2, PAGE_SIZE,
+					calls->xor_syndrome(NDISKS, p1, p2, PAGE_SIZE,
 								(void **)&dataptrs);
 					makedata(p1, p2);
-					raid6_call.xor_syndrome(NDISKS, p1, p2, PAGE_SIZE,
+					calls->xor_syndrome(NDISKS, p1, p2, PAGE_SIZE,
                                                                 (void **)&dataptrs);
 
 					for (i = 0; i < NDISKS-1; i++)
 						for (j = i+1; j < NDISKS; j++)
-							err += test_disks(i, j);
+							test_disks(test, calls,
+									*ra, i, j);
 				}
 
 		}
-		printf("\n");
 	}
+}
 
-	printf("\n");
-	/* Pick the best algorithm test */
-	raid6_select_algo();
-
-	if (err)
-		printf("\n*** ERRORS FOUND ***\n");
+static struct kunit_case raid6_test_cases[] = {
+	KUNIT_CASE(raid6_test),
+	{},
+};
 
-	return err;
+static int raid6_suite_init(struct kunit_suite *suite)
+{
+	prandom_seed_state(&rng, RAID6_KUNIT_SEED);
+	makedata(0, NDISKS - 1);
+	return 0;
 }
+
+static struct kunit_suite raid6_test_suite = {
+	.name		= "raid6",
+	.test_cases	= raid6_test_cases,
+	.suite_init	= raid6_suite_init,
+};
+kunit_test_suite(raid6_test_suite);
+
+MODULE_DESCRIPTION("Unit test for the RAID P/Q library functions");
+MODULE_LICENSE("GPL");