[PATCH RESEND v3 0/5] test_hash.c: refactor into KUnit

[PATCH RESEND v3 0/5] test_hash.c: refactor into KUnit

[Isabella Basso]

We refactored the lib/test_hash.c file into KUnit as part of the student
group LKCAMP [1] introductory hackathon for kernel development.

This test was pointed to our group by Daniel Latypov [2], so its full
conversion into a pure KUnit test was our goal in this patch series, but
we ran into many problems relating to it not being split as unit tests,
which complicated matters a bit, as the reasoning behind the original
tests is quite cryptic for those unfamiliar with hash implementations.

Some interesting developments we'd like to highlight are:

- In patch 1/5 we noticed that there was an unused define directive that
  could be removed.
- In patch 4/5 we noticed how stringhash and hash tests are all under
  the lib/test_hash.c file, which might cause some confusion, and we
  also broke those kernel config entries up.

Overall KUnit developments have been made in the other patches in this
series:

In patches 2/5, 3/5 and 5/5 we refactored the lib/test_hash.c
file so as to make it more compatible with the KUnit style, whilst
preserving the original idea of the maintainer who designed it (i.e.
George Spelvin), which might be undesirable for unit tests, but we
assume it is enough for a first patch.

This is our first patch series so we hope our contributions are
interesting and also hope to get some useful criticism from the
community. :)

Changes since v2:
- Added comments on struct elements.
- Removed unecessary __init bits from KUnit test functions.
- Change KUnit's "EXPECT_FALSE"s for "EXPECT_EQ"s.
Changes since v1:
- Fixed compilation on parisc and m68k.
- Fixed whitespace mistakes.
- Renamed a few functions.
- Refactored globals into struct for test function params, thus removing
  a patch.
- Reworded some commit messages.

[1] - https://lkcamp.dev/
[2] - https://lore.kernel.org/linux-kselftest/CAGS_qxojszgM19u=3HLwFgKX5bm5KhywvsSunuBAt5RtR+GyxQ@mail.gmail.com/

Isabella Basso (5):
  hash.h: remove unused define directive
  test_hash.c: split test_int_hash into arch-specific functions
  test_hash.c: split test_hash_init
  lib/Kconfig.debug: properly split hash test kernel entries
  test_hash.c: refactor into kunit

 include/linux/hash.h       |   5 +-
 lib/Kconfig.debug          |  28 +++-
 lib/Makefile               |   3 +-
 lib/test_hash.c            | 259 +++++++++++++++++--------------------
 tools/include/linux/hash.h |   5 +-
 5 files changed, 147 insertions(+), 153 deletions(-)

-- 
2.34.1

[PATCH RESEND v3 1/5] hash.h: remove unused define directive

[Isabella Basso]

Currently, there exist hash_32() and __hash_32() functions, which were
introduced in a patch [1] targeting architecture specific optimizations.
These functions can be overridden on a per-architecture basis to achieve
such optimizations. They must set their corresponding define directive
(HAVE_ARCH_HASH_32 and HAVE_ARCH__HASH_32, respectively) so that header
files can deal with these overrides properly.

As the supported 32-bit architectures that have their own hash function
implementation (i.e. m68k, Microblaze, H8/300, pa-risc) have only been
making use of the (more general) __hash_32() function (which only lacks
a right shift operation when compared to the hash_32() function),
remove the define directive corresponding to the arch-specific hash_32()
implementation.

[1] https://lore.kernel.org/lkml/20160525073311.5600.qmail@ns.sciencehorizons.net/

Reviewed-by: David Gow <davidgow@google.com>
Tested-by: David Gow <davidgow@google.com>
Co-developed-by: Augusto Durães Camargo <augusto.duraes33@gmail.com>
Signed-off-by: Augusto Durães Camargo <augusto.duraes33@gmail.com>
Co-developed-by: Enzo Ferreira <ferreiraenzoa@gmail.com>
Signed-off-by: Enzo Ferreira <ferreiraenzoa@gmail.com>
Signed-off-by: Isabella Basso <isabbasso@riseup.net>
---
Changes since v1:
- As suggested by David Gow:
  1. Reword commit message.

 include/linux/hash.h       |  5 +----
 lib/test_hash.c            | 24 +-----------------------
 tools/include/linux/hash.h |  5 +----
 3 files changed, 3 insertions(+), 31 deletions(-)

diff --git a/include/linux/hash.h b/include/linux/hash.h
index ad6fa21d977b..38edaa08f862 100644
--- a/include/linux/hash.h
+++ b/include/linux/hash.h
@@ -62,10 +62,7 @@ static inline u32 __hash_32_generic(u32 val)
 	return val * GOLDEN_RATIO_32;
 }
 
-#ifndef HAVE_ARCH_HASH_32
-#define hash_32 hash_32_generic
-#endif
-static inline u32 hash_32_generic(u32 val, unsigned int bits)
+static inline u32 hash_32(u32 val, unsigned int bits)
 {
 	/* High bits are more random, so use them. */
 	return __hash_32(val) >> (32 - bits);
diff --git a/lib/test_hash.c b/lib/test_hash.c
index 0ee40b4a56dd..d4b0cfdb0377 100644
--- a/lib/test_hash.c
+++ b/lib/test_hash.c
@@ -94,22 +94,7 @@ test_int_hash(unsigned long long h64, u32 hash_or[2][33])
 			pr_err("hash_32(%#x, %d) = %#x > %#x", h0, k, h1, m);
 			return false;
 		}
-#ifdef HAVE_ARCH_HASH_32
-		h2 = hash_32_generic(h0, k);
-#if HAVE_ARCH_HASH_32 == 1
-		if (h1 != h2) {
-			pr_err("hash_32(%#x, %d) = %#x != hash_32_generic() "
-				" = %#x", h0, k, h1, h2);
-			return false;
-		}
-#else
-		if (h2 > m) {
-			pr_err("hash_32_generic(%#x, %d) = %#x > %#x",
-				h0, k, h1, m);
-			return false;
-		}
-#endif
-#endif
+
 		/* Test hash_64 */
 		hash_or[1][k] |= h1 = hash_64(h64, k);
 		if (h1 > m) {
@@ -227,13 +212,6 @@ test_hash_init(void)
 #else
 	pr_info("__hash_32() has no arch implementation to test.");
 #endif
-#ifdef HAVE_ARCH_HASH_32
-#if HAVE_ARCH_HASH_32 != 1
-	pr_info("hash_32() is arch-specific; not compared to generic.");
-#endif
-#else
-	pr_info("hash_32() has no arch implementation to test.");
-#endif
 #ifdef HAVE_ARCH_HASH_64
 #if HAVE_ARCH_HASH_64 != 1
 	pr_info("hash_64() is arch-specific; not compared to generic.");
diff --git a/tools/include/linux/hash.h b/tools/include/linux/hash.h
index ad6fa21d977b..38edaa08f862 100644
--- a/tools/include/linux/hash.h
+++ b/tools/include/linux/hash.h
@@ -62,10 +62,7 @@ static inline u32 __hash_32_generic(u32 val)
 	return val * GOLDEN_RATIO_32;
 }
 
-#ifndef HAVE_ARCH_HASH_32
-#define hash_32 hash_32_generic
-#endif
-static inline u32 hash_32_generic(u32 val, unsigned int bits)
+static inline u32 hash_32(u32 val, unsigned int bits)
 {
 	/* High bits are more random, so use them. */
 	return __hash_32(val) >> (32 - bits);
-- 
2.34.1

[PATCH RESEND v3 2/5] test_hash.c: split test_int_hash into arch-specific functions

[Isabella Basso]

Split the test_int_hash function to keep its mainloop separate from
arch-specific chunks, which are only compiled as needed. This aims at
improving readability.

Reviewed-by: David Gow <davidgow@google.com>
Tested-by: David Gow <davidgow@google.com>
Signed-off-by: Isabella Basso <isabbasso@riseup.net>
---
Changes since v2:
- As suggested by David Gow:
  1. Add comments to struct elements.
Changes since v1:
- As suggested by Marco Elver:
  1. Add struct for carrying test variables.

 lib/test_hash.c | 91 +++++++++++++++++++++++++++++++++----------------
 1 file changed, 62 insertions(+), 29 deletions(-)

diff --git a/lib/test_hash.c b/lib/test_hash.c
index d4b0cfdb0377..2b4fe4976cc4 100644
--- a/lib/test_hash.c
+++ b/lib/test_hash.c
@@ -56,6 +56,58 @@ fill_buf(char *buf, size_t len, u32 seed)
 	}
 }
 
+/* Holds most testing variables for the int test. */
+struct test_hash_params {
+        /* Pointer to integer to be hashed. */
+	unsigned long long *h64;
+        /* Low 32-bits of integer to be hashed. */
+	u32 h0;
+        /* Arch-specific hash result. */
+	u32 h1;
+        /* Generic hash result. */
+	u32 h2;
+        /* ORed hashes of given size (in bits). */
+	u32 (*hash_or)[33];
+};
+
+#ifdef HAVE_ARCH__HASH_32
+static bool __init
+test_int__hash_32(struct test_hash_params *params)
+{
+	params->hash_or[1][0] |= params->h2 = __hash_32_generic(params->h0);
+#if HAVE_ARCH__HASH_32 == 1
+	if (params->h1 != params->h2) {
+		pr_err("__hash_32(%#x) = %#x != __hash_32_generic() = %#x",
+		       params->h0, params->h1, params->h2);
+		return false;
+	}
+#endif
+	return true;
+}
+#endif
+
+#ifdef HAVE_ARCH_HASH_64
+static bool __init
+test_int_hash_64(struct test_hash_params *params, u32 const *m, int *k)
+{
+	params->h2 = hash_64_generic(*params->h64, *k);
+#if HAVE_ARCH_HASH_64 == 1
+	if (params->h1 != params->h2) {
+		pr_err("hash_64(%#llx, %d) = %#x != hash_64_generic() = %#x",
+		       *params->h64, *k, params->h1, params->h2);
+		return false;
+	}
+#else
+	if (params->h2 > *m) {
+		pr_err("hash_64_generic(%#llx, %d) = %#x > %#x",
+		       *params->h64, *k, params->h1, *m);
+		return false;
+	}
+#endif
+	return true;
+}
+#endif
+
 /*
  * Test the various integer hash functions.  h64 (or its low-order bits)
  * is the integer to hash.  hash_or accumulates the OR of the hash values,
@@ -69,19 +121,13 @@ static bool __init
 test_int_hash(unsigned long long h64, u32 hash_or[2][33])
 {
 	int k;
-	u32 h0 = (u32)h64, h1, h2;
+	struct test_hash_params params = { &h64, (u32)h64, 0, 0, hash_or };
 
 	/* Test __hash32 */
-	hash_or[0][0] |= h1 = __hash_32(h0);
+	hash_or[0][0] |= params.h1 = __hash_32(params.h0);
 #ifdef HAVE_ARCH__HASH_32
-	hash_or[1][0] |= h2 = __hash_32_generic(h0);
-#if HAVE_ARCH__HASH_32 == 1
-	if (h1 != h2) {
-		pr_err("__hash_32(%#x) = %#x != __hash_32_generic() = %#x",
-			h0, h1, h2);
+	if (!test_int__hash_32(&params))
 		return false;
-	}
-#endif
 #endif
 
 	/* Test k = 1..32 bits */
@@ -89,37 +135,24 @@ test_int_hash(unsigned long long h64, u32 hash_or[2][33])
 		u32 const m = ((u32)2 << (k-1)) - 1;	/* Low k bits set */
 
 		/* Test hash_32 */
-		hash_or[0][k] |= h1 = hash_32(h0, k);
-		if (h1 > m) {
-			pr_err("hash_32(%#x, %d) = %#x > %#x", h0, k, h1, m);
+		hash_or[0][k] |= params.h1 = hash_32(params.h0, k);
+		if (params.h1 > m) {
+			pr_err("hash_32(%#x, %d) = %#x > %#x", params.h0, k, params.h1, m);
 			return false;
 		}
 
 		/* Test hash_64 */
-		hash_or[1][k] |= h1 = hash_64(h64, k);
-		if (h1 > m) {
-			pr_err("hash_64(%#llx, %d) = %#x > %#x", h64, k, h1, m);
+		hash_or[1][k] |= params.h1 = hash_64(h64, k);
+		if (params.h1 > m) {
+			pr_err("hash_64(%#llx, %d) = %#x > %#x", h64, k, params.h1, m);
 			return false;
 		}
 #ifdef HAVE_ARCH_HASH_64
-		h2 = hash_64_generic(h64, k);
-#if HAVE_ARCH_HASH_64 == 1
-		if (h1 != h2) {
-			pr_err("hash_64(%#llx, %d) = %#x != hash_64_generic() "
-				"= %#x", h64, k, h1, h2);
+		if (!test_int_hash_64(&params, &m, &k))
 			return false;
-		}
-#else
-		if (h2 > m) {
-			pr_err("hash_64_generic(%#llx, %d) = %#x > %#x",
-				h64, k, h1, m);
-			return false;
-		}
-#endif
 #endif
 	}
 
-	(void)h2;	/* Suppress unused variable warning */
 	return true;
 }
 
-- 
2.34.1

[PATCH RESEND v3 3/5] test_hash.c: split test_hash_init

[Isabella Basso]

Split up test_hash_init so that it calls each test more explicitly
insofar it is possible without rewriting the entire file. This aims at
improving readability.

Split tests performed on string_or as they don't interfere with those
performed in hash_or. Also separate pr_info calls about skipped tests as
they're not part of the tests themselves, but only warn about
(un)defined arch-specific hash functions.

Reviewed-by: David Gow <davidgow@google.com>
Tested-by: David Gow <davidgow@google.com>
Signed-off-by: Isabella Basso <isabbasso@riseup.net>
---
Changes since v1:
- As suggested by David Gow:
  1. Rename arch-specific test functions.
  2. Remove spare whitespace changes.

 lib/test_hash.c | 66 ++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 54 insertions(+), 12 deletions(-)

diff --git a/lib/test_hash.c b/lib/test_hash.c
index 2b4fe4976cc4..032849a48da7 100644
--- a/lib/test_hash.c
+++ b/lib/test_hash.c
@@ -158,11 +158,39 @@ test_int_hash(unsigned long long h64, u32 hash_or[2][33])
 
 #define SIZE 256	/* Run time is cubic in SIZE */
 
-static int __init
-test_hash_init(void)
+static int __init test_string_or(void)
 {
 	char buf[SIZE+1];
-	u32 string_or = 0, hash_or[2][33] = { { 0, } };
+	u32 string_or = 0;
+	int i, j;
+
+	fill_buf(buf, SIZE, 1);
+
+	/* Test every possible non-empty substring in the buffer. */
+	for (j = SIZE; j > 0; --j) {
+		buf[j] = '\0';
+
+		for (i = 0; i <= j; i++) {
+			u32 h0 = full_name_hash(buf+i, buf+i, j-i);
+
+			string_or |= h0;
+		} /* i */
+	} /* j */
+
+	/* The OR of all the hash values should cover all the bits */
+	if (~string_or) {
+		pr_err("OR of all string hash results = %#x != %#x",
+		       string_or, -1u);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int __init test_hash_or(void)
+{
+	char buf[SIZE+1];
+	u32 hash_or[2][33] = { { 0, } };
 	unsigned tests = 0;
 	unsigned long long h64 = 0;
 	int i, j;
@@ -192,7 +220,6 @@ test_hash_init(void)
 				return -EINVAL;
 			}
 
-			string_or |= h0;
 			h64 = h64 << 32 | h0;	/* For use with hash_64 */
 			if (!test_int_hash(h64, hash_or))
 				return -EINVAL;
@@ -200,12 +227,6 @@ test_hash_init(void)
 		} /* i */
 	} /* j */
 
-	/* The OR of all the hash values should cover all the bits */
-	if (~string_or) {
-		pr_err("OR of all string hash results = %#x != %#x",
-			string_or, -1u);
-		return -EINVAL;
-	}
 	if (~hash_or[0][0]) {
 		pr_err("OR of all __hash_32 results = %#x != %#x",
 			hash_or[0][0], -1u);
@@ -237,6 +258,13 @@ test_hash_init(void)
 		}
 	}
 
+	pr_notice("%u tests passed.", tests);
+
+	return 0;
+}
+
+static void __init notice_skipped_tests(void)
+{
 	/* Issue notices about skipped tests. */
 #ifdef HAVE_ARCH__HASH_32
 #if HAVE_ARCH__HASH_32 != 1
@@ -252,10 +280,24 @@ test_hash_init(void)
 #else
 	pr_info("hash_64() has no arch implementation to test.");
 #endif
+}
 
-	pr_notice("%u tests passed.", tests);
+static int __init
+test_hash_init(void)
+{
+	int ret;
 
-	return 0;
+	ret = test_string_or();
+	if (ret < 0)
+		return ret;
+
+	ret = test_hash_or();
+	if (ret < 0)
+		return ret;
+
+	notice_skipped_tests();
+
+	return ret;
 }
 
 static void __exit test_hash_exit(void)
-- 
2.34.1

[PATCH RESEND v3 4/5] lib/Kconfig.debug: properly split hash test kernel entries

[Isabella Basso]

Split TEST_HASH so that each entry only has one file.

Note that there's no stringhash test file, but actually
<linux/stringhash.h> tests are performed in lib/test_hash.c.

Reviewed-by: David Gow <davidgow@google.com>
Tested-by: David Gow <davidgow@google.com>
Signed-off-by: Isabella Basso <isabbasso@riseup.net>
---
 lib/Kconfig.debug | 14 +++++++++++---
 lib/Makefile      |  3 ++-
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 5c12bde10996..e5f43d423bc9 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2209,9 +2209,17 @@ config TEST_RHASHTABLE
 config TEST_HASH
 	tristate "Perform selftest on hash functions"
 	help
-	  Enable this option to test the kernel's integer (<linux/hash.h>),
-	  string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
-	  hash functions on boot (or module load).
+	  Enable this option to test the kernel's integer (<linux/hash.h>), and
+	  string (<linux/stringhash.h>) hash functions on boot (or module load).
+
+	  This is intended to help people writing architecture-specific
+	  optimized versions.  If unsure, say N.
+
+config TEST_SIPHASH
+	tristate "Perform selftest on siphash functions"
+	help
+	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
+	  functions on boot (or module load).
 
 	  This is intended to help people writing architecture-specific
 	  optimized versions.  If unsure, say N.
diff --git a/lib/Makefile b/lib/Makefile
index 364c23f15578..f3a2a251471d 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -61,7 +61,8 @@ obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
 obj-$(CONFIG_TEST_BITOPS) += test_bitops.o
 CFLAGS_test_bitops.o += -Werror
 obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o
-obj-$(CONFIG_TEST_HASH) += test_hash.o test_siphash.o
+obj-$(CONFIG_TEST_SIPHASH) += test_siphash.o
+obj-$(CONFIG_TEST_HASH) += test_hash.o
 obj-$(CONFIG_TEST_IDA) += test_ida.o
 obj-$(CONFIG_KASAN_KUNIT_TEST) += test_kasan.o
 CFLAGS_test_kasan.o += -fno-builtin
-- 
2.34.1

[PATCH RESEND v3 5/5] test_hash.c: refactor into kunit

[Isabella Basso]

Use KUnit framework to make tests more easily integrable with CIs. Even
though these tests are not yet properly written as unit tests this
change should help in debugging.

Also remove kernel messages (i.e. through pr_info) as KUnit handles all
debugging output and let it handle module init and exit details.

Reviewed-by: David Gow <davidgow@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Tested-by: David Gow <davidgow@google.com>
Co-developed-by: Augusto Durães Camargo <augusto.duraes33@gmail.com>
Signed-off-by: Augusto Durães Camargo <augusto.duraes33@gmail.com>
Co-developed-by: Enzo Ferreira <ferreiraenzoa@gmail.com>
Signed-off-by: Enzo Ferreira <ferreiraenzoa@gmail.com>
Signed-off-by: Isabella Basso <isabbasso@riseup.net>
---
Changes since v2:
- As suggested by David Gow:
  1. Remove unnecessary __init from functions.
  2. Change KUnit's "EXPECT_FALSE"s for "EXPECT_EQ"s.
Changes since v1:
- As suggested by David Gow:
  1. Keep module support.
  2. Reword commit message.
- As reported by the kernel test bot:
  1. Fix compilation for m68k and parisc architectures.

 lib/Kconfig.debug |  28 ++++---
 lib/Makefile      |   2 +-
 lib/test_hash.c   | 194 +++++++++++++++-------------------------------
 3 files changed, 81 insertions(+), 143 deletions(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index e5f43d423bc9..3f56f5ab007a 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2206,15 +2206,6 @@ config TEST_RHASHTABLE
 
 	  If unsure, say N.
 
-config TEST_HASH
-	tristate "Perform selftest on hash functions"
-	help
-	  Enable this option to test the kernel's integer (<linux/hash.h>), and
-	  string (<linux/stringhash.h>) hash functions on boot (or module load).
-
-	  This is intended to help people writing architecture-specific
-	  optimized versions.  If unsure, say N.
-
 config TEST_SIPHASH
 	tristate "Perform selftest on siphash functions"
 	help
@@ -2363,6 +2354,25 @@ config BITFIELD_KUNIT
 
 	  If unsure, say N.
 
+config HASH_KUNIT_TEST
+	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
+	  integer (<linux/hash.h>) hash functions on boot.
+
+	  KUnit tests run during boot and output the results to the debug log
+	  in TAP format (https://testanything.org/). Only useful for kernel devs
+	  running the KUnit test harness, and not intended for inclusion into a
+	  production build.
+
+	  For more information on KUnit and unit tests in general please refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+	  This is intended to help people writing architecture-specific
+	  optimized versions. If unsure, say N.
+
 config RESOURCE_KUNIT_TEST
 	tristate "KUnit test for resource API"
 	depends on KUNIT
diff --git a/lib/Makefile b/lib/Makefile
index f3a2a251471d..511c27827701 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -62,7 +62,7 @@ obj-$(CONFIG_TEST_BITOPS) += test_bitops.o
 CFLAGS_test_bitops.o += -Werror
 obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o
 obj-$(CONFIG_TEST_SIPHASH) += test_siphash.o
-obj-$(CONFIG_TEST_HASH) += test_hash.o
+obj-$(CONFIG_HASH_KUNIT_TEST) += test_hash.o
 obj-$(CONFIG_TEST_IDA) += test_ida.o
 obj-$(CONFIG_KASAN_KUNIT_TEST) += test_kasan.o
 CFLAGS_test_kasan.o += -fno-builtin
diff --git a/lib/test_hash.c b/lib/test_hash.c
index 032849a48da7..bb25fda34794 100644
--- a/lib/test_hash.c
+++ b/lib/test_hash.c
@@ -14,17 +14,15 @@
  * and hash_64().
  */
 
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt "\n"
-
 #include <linux/compiler.h>
 #include <linux/types.h>
 #include <linux/module.h>
 #include <linux/hash.h>
 #include <linux/stringhash.h>
-#include <linux/printk.h>
+#include <kunit/test.h>
 
 /* 32-bit XORSHIFT generator.  Seed must not be zero. */
-static u32 __init __attribute_const__
+static u32 __attribute_const__
 xorshift(u32 seed)
 {
 	seed ^= seed << 13;
@@ -34,7 +32,7 @@ xorshift(u32 seed)
 }
 
 /* Given a non-zero x, returns a non-zero byte. */
-static u8 __init __attribute_const__
+static u8 __attribute_const__
 mod255(u32 x)
 {
 	x = (x & 0xffff) + (x >> 16);	/* 1 <= x <= 0x1fffe */
@@ -45,8 +43,7 @@ mod255(u32 x)
 }
 
 /* Fill the buffer with non-zero bytes. */
-static void __init
-fill_buf(char *buf, size_t len, u32 seed)
+static void fill_buf(char *buf, size_t len, u32 seed)
 {
 	size_t i;
 
@@ -71,40 +68,32 @@ struct test_hash_params {
 };
 
 #ifdef HAVE_ARCH__HASH_32
-static bool __init
-test_int__hash_32(struct test_hash_params *params)
+static void
+test_int__hash_32(struct kunit *test, struct test_hash_params *params)
 {
 	params->hash_or[1][0] |= params->h2 = __hash_32_generic(params->h0);
 #if HAVE_ARCH__HASH_32 == 1
-	if (params->h1 != params->h2) {
-		pr_err("__hash_32(%#x) = %#x != __hash_32_generic() = %#x",
-		       params->h0, params->h1, params->h2);
-		return false;
-	}
+	KUNIT_EXPECT_EQ_MSG(test, params->h1, params->h2,
+			    "__hash_32(%#x) = %#x != __hash_32_generic() = %#x",
+			    params->h0, params->h1, params->h2);
 #endif
-	return true;
 }
 #endif
 
 #ifdef HAVE_ARCH_HASH_64
-static bool __init
-test_int_hash_64(struct test_hash_params *params, u32 const *m, int *k)
+static void
+test_int_hash_64(struct kunit *test, struct test_hash_params *params, u32 const *m, int *k)
 {
 	params->h2 = hash_64_generic(*params->h64, *k);
 #if HAVE_ARCH_HASH_64 == 1
-	if (params->h1 != params->h2) {
-		pr_err("hash_64(%#llx, %d) = %#x != hash_64_generic() = %#x",
-		       *params->h64, *k, params->h1, params->h2);
-		return false;
-	}
+	KUNIT_EXPECT_EQ_MSG(test, params->h1, params->h2,
+			    "hash_64(%#llx, %d) = %#x != hash_64_generic() = %#x",
+			    *params->h64, *k, params->h1, params->h2);
 #else
-	if (params->h2 > *m) {
-		pr_err("hash_64_generic(%#llx, %d) = %#x > %#x",
-		       *params->h64, *k, params->h1, *m);
-		return false;
-	}
+	KUNIT_EXPECT_LE_MSG(test, params->h1, params->h2,
+			    "hash_64_generic(%#llx, %d) = %#x > %#x",
+			    *params->h64, *k, params->h1, *m);
 #endif
-	return true;
 }
 #endif
 
@@ -117,8 +106,8 @@ test_int_hash_64(struct test_hash_params *params, u32 const *m, int *k)
  * inline, the code being tested is actually in the module, and you can
  * recompile and re-test the module without rebooting.
  */
-static bool __init
-test_int_hash(unsigned long long h64, u32 hash_or[2][33])
+static void
+test_int_hash(struct kunit *test, unsigned long long h64, u32 hash_or[2][33])
 {
 	int k;
 	struct test_hash_params params = { &h64, (u32)h64, 0, 0, hash_or };
@@ -126,8 +115,7 @@ test_int_hash(unsigned long long h64, u32 hash_or[2][33])
 	/* Test __hash32 */
 	hash_or[0][0] |= params.h1 = __hash_32(params.h0);
 #ifdef HAVE_ARCH__HASH_32
-	if (!test_int__hash_32(&params))
-		return false;
+	test_int__hash_32(test, &params);
 #endif
 
 	/* Test k = 1..32 bits */
@@ -136,29 +124,24 @@ test_int_hash(unsigned long long h64, u32 hash_or[2][33])
 
 		/* Test hash_32 */
 		hash_or[0][k] |= params.h1 = hash_32(params.h0, k);
-		if (params.h1 > m) {
-			pr_err("hash_32(%#x, %d) = %#x > %#x", params.h0, k, params.h1, m);
-			return false;
-		}
+		KUNIT_EXPECT_LE_MSG(test, params.h1, m,
+				    "hash_32(%#x, %d) = %#x > %#x",
+				    params.h0, k, params.h1, m);
 
 		/* Test hash_64 */
 		hash_or[1][k] |= params.h1 = hash_64(h64, k);
-		if (params.h1 > m) {
-			pr_err("hash_64(%#llx, %d) = %#x > %#x", h64, k, params.h1, m);
-			return false;
-		}
+		KUNIT_EXPECT_LE_MSG(test, params.h1, m,
+				    "hash_64(%#llx, %d) = %#x > %#x",
+				    h64, k, params.h1, m);
 #ifdef HAVE_ARCH_HASH_64
-		if (!test_int_hash_64(&params, &m, &k))
-			return false;
+		test_int_hash_64(test, &params, &m, &k);
 #endif
 	}
-
-	return true;
 }
 
 #define SIZE 256	/* Run time is cubic in SIZE */
 
-static int __init test_string_or(void)
+static void test_string_or(struct kunit *test)
 {
 	char buf[SIZE+1];
 	u32 string_or = 0;
@@ -178,20 +161,15 @@ static int __init test_string_or(void)
 	} /* j */
 
 	/* The OR of all the hash values should cover all the bits */
-	if (~string_or) {
-		pr_err("OR of all string hash results = %#x != %#x",
-		       string_or, -1u);
-		return -EINVAL;
-	}
-
-	return 0;
+	KUNIT_EXPECT_EQ_MSG(test, string_or, -1u,
+			    "OR of all string hash results = %#x != %#x",
+			    string_or, -1u);
 }
 
-static int __init test_hash_or(void)
+static void test_hash_or(struct kunit *test)
 {
 	char buf[SIZE+1];
 	u32 hash_or[2][33] = { { 0, } };
-	unsigned tests = 0;
 	unsigned long long h64 = 0;
 	int i, j;
 
@@ -206,39 +184,27 @@ static int __init test_hash_or(void)
 			u32 h0 = full_name_hash(buf+i, buf+i, j-i);
 
 			/* Check that hashlen_string gets the length right */
-			if (hashlen_len(hashlen) != j-i) {
-				pr_err("hashlen_string(%d..%d) returned length"
-					" %u, expected %d",
-					i, j, hashlen_len(hashlen), j-i);
-				return -EINVAL;
-			}
+			KUNIT_EXPECT_EQ_MSG(test, hashlen_len(hashlen), j-i,
+					    "hashlen_string(%d..%d) returned length %u, expected %d",
+					    i, j, hashlen_len(hashlen), j-i);
 			/* Check that the hashes match */
-			if (hashlen_hash(hashlen) != h0) {
-				pr_err("hashlen_string(%d..%d) = %08x != "
-					"full_name_hash() = %08x",
-					i, j, hashlen_hash(hashlen), h0);
-				return -EINVAL;
-			}
+			KUNIT_EXPECT_EQ_MSG(test, hashlen_hash(hashlen), h0,
+					    "hashlen_string(%d..%d) = %08x != full_name_hash() = %08x",
+					    i, j, hashlen_hash(hashlen), h0);
 
 			h64 = h64 << 32 | h0;	/* For use with hash_64 */
-			if (!test_int_hash(h64, hash_or))
-				return -EINVAL;
-			tests++;
+			test_int_hash(test, h64, hash_or);
 		} /* i */
 	} /* j */
 
-	if (~hash_or[0][0]) {
-		pr_err("OR of all __hash_32 results = %#x != %#x",
-			hash_or[0][0], -1u);
-		return -EINVAL;
-	}
+	KUNIT_EXPECT_EQ_MSG(test, hash_or[0][0], -1u,
+			    "OR of all __hash_32 results = %#x != %#x",
+			    hash_or[0][0], -1u);
 #ifdef HAVE_ARCH__HASH_32
 #if HAVE_ARCH__HASH_32 != 1	/* Test is pointless if results match */
-	if (~hash_or[1][0]) {
-		pr_err("OR of all __hash_32_generic results = %#x != %#x",
-			hash_or[1][0], -1u);
-		return -EINVAL;
-	}
+	KUNIT_EXPECT_EQ_MSG(test, hash_or[1][0], -1u,
+			    "OR of all __hash_32_generic results = %#x != %#x",
+			    hash_or[1][0], -1u);
 #endif
 #endif
 
@@ -246,65 +212,27 @@ static int __init test_hash_or(void)
 	for (i = 1; i <= 32; i++) {
 		u32 const m = ((u32)2 << (i-1)) - 1;	/* Low i bits set */
 
-		if (hash_or[0][i] != m) {
-			pr_err("OR of all hash_32(%d) results = %#x "
-				"(%#x expected)", i, hash_or[0][i], m);
-			return -EINVAL;
-		}
-		if (hash_or[1][i] != m) {
-			pr_err("OR of all hash_64(%d) results = %#x "
-				"(%#x expected)", i, hash_or[1][i], m);
-			return -EINVAL;
-		}
+		KUNIT_EXPECT_EQ_MSG(test, hash_or[0][i], m,
+				    "OR of all hash_32(%d) results = %#x (%#x expected)",
+				    i, hash_or[0][i], m);
+		KUNIT_EXPECT_EQ_MSG(test, hash_or[1][i], m,
+				    "OR of all hash_64(%d) results = %#x (%#x expected)",
+				    i, hash_or[1][i], m);
 	}
-
-	pr_notice("%u tests passed.", tests);
-
-	return 0;
 }
 
-static void __init notice_skipped_tests(void)
-{
-	/* Issue notices about skipped tests. */
-#ifdef HAVE_ARCH__HASH_32
-#if HAVE_ARCH__HASH_32 != 1
-	pr_info("__hash_32() is arch-specific; not compared to generic.");
-#endif
-#else
-	pr_info("__hash_32() has no arch implementation to test.");
-#endif
-#ifdef HAVE_ARCH_HASH_64
-#if HAVE_ARCH_HASH_64 != 1
-	pr_info("hash_64() is arch-specific; not compared to generic.");
-#endif
-#else
-	pr_info("hash_64() has no arch implementation to test.");
-#endif
-}
-
-static int __init
-test_hash_init(void)
-{
-	int ret;
-
-	ret = test_string_or();
-	if (ret < 0)
-		return ret;
-
-	ret = test_hash_or();
-	if (ret < 0)
-		return ret;
-
-	notice_skipped_tests();
+static struct kunit_case hash_test_cases[] __refdata = {
+	KUNIT_CASE(test_string_or),
+	KUNIT_CASE(test_hash_or),
+	{}
+};
 
-	return ret;
-}
+static struct kunit_suite hash_test_suite = {
+	.name = "hash",
+	.test_cases = hash_test_cases,
+};
 
-static void __exit test_hash_exit(void)
-{
-}
 
-module_init(test_hash_init);	/* Does everything */
-module_exit(test_hash_exit);	/* Does nothing */
+kunit_test_suite(hash_test_suite);
 
 MODULE_LICENSE("GPL");
-- 
2.34.1

Re: [PATCH RESEND v3 0/5] test_hash.c: refactor into KUnit

[David Gow]

On Thu, Dec 9, 2021 at 2:37 AM Isabella Basso <isabbasso@riseup.net> wrote:
>
> We refactored the lib/test_hash.c file into KUnit as part of the student
> group LKCAMP [1] introductory hackathon for kernel development.
>
> This test was pointed to our group by Daniel Latypov [2], so its full
> conversion into a pure KUnit test was our goal in this patch series, but
> we ran into many problems relating to it not being split as unit tests,
> which complicated matters a bit, as the reasoning behind the original
> tests is quite cryptic for those unfamiliar with hash implementations.
>
> Some interesting developments we'd like to highlight are:
>
> - In patch 1/5 we noticed that there was an unused define directive that
>   could be removed.
> - In patch 4/5 we noticed how stringhash and hash tests are all under
>   the lib/test_hash.c file, which might cause some confusion, and we
>   also broke those kernel config entries up.
>
> Overall KUnit developments have been made in the other patches in this
> series:
>
> In patches 2/5, 3/5 and 5/5 we refactored the lib/test_hash.c
> file so as to make it more compatible with the KUnit style, whilst
> preserving the original idea of the maintainer who designed it (i.e.
> George Spelvin), which might be undesirable for unit tests, but we
> assume it is enough for a first patch.
>
> This is our first patch series so we hope our contributions are
> interesting and also hope to get some useful criticism from the
> community. :)
>
> Changes since v2:
> - Added comments on struct elements.
> - Removed unecessary __init bits from KUnit test functions.
> - Change KUnit's "EXPECT_FALSE"s for "EXPECT_EQ"s.
> Changes since v1:
> - Fixed compilation on parisc and m68k.
> - Fixed whitespace mistakes.
> - Renamed a few functions.
> - Refactored globals into struct for test function params, thus removing
>   a patch.
> - Reworded some commit messages.
>
> [1] - https://lkcamp.dev/
> [2] - https://lore.kernel.org/linux-kselftest/CAGS_qxojszgM19u=3HLwFgKX5bm5KhywvsSunuBAt5RtR+GyxQ@mail.gmail.com/

This series still works fine for me, and is still:

Tested-by: David Gow <davidgow@google.com>
Reviewed-by: David Gow <davidgow@google.com>

Hopefully we can get this in soon!

Thanks,
-- David