Subject: [PATCH v2 09/12] lib/crc16_kunit: delete obsolete crc16_kunit.c

From: Eric Biggers <[email-masked]>
Date: Sun, 1 Dec 2024 17:20:53 -0800

From: Eric Biggers <[email-masked]>

This new test showed up in v6.13-rc1.  Delete it since it is being
superseded by crc_kunit.c, which is more comprehensive (tests multiple
CRC variants without duplicating code, includes a benchmark, etc.).

Cc: Vinicius Peixoto <[email-masked]>
Signed-off-by: Eric Biggers <[email-masked]>
---
 lib/Kconfig.debug |   9 ---
 lib/Makefile      |   1 -
 lib/crc16_kunit.c | 155 ----------------------------------------------
 3 files changed, 165 deletions(-)
 delete mode 100644 lib/crc16_kunit.c

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index d9b89dd3f6a0..688dace36f36 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2876,19 +2876,10 @@ config USERCOPY_KUNIT_TEST
 	help
 	  This builds the "usercopy_kunit" module that runs sanity checks
 	  on the copy_to/from_user infrastructure, making sure basic
 	  user/kernel boundary testing is working.
 
-config CRC16_KUNIT_TEST
-	tristate "KUnit tests for CRC16"
-	depends on KUNIT
-	default KUNIT_ALL_TESTS
-	select CRC16
-	help
-	  Enable this option to run unit tests for the kernel's CRC16
-	  implementation (<linux/crc16.h>).
-
 config TEST_UDELAY
 	tristate "udelay test driver"
 	help
 	  This builds the "udelay_test" module that helps to make sure
 	  that udelay() is working properly.
diff --git a/lib/Makefile b/lib/Makefile
index ccd803d03e58..34f4d61e3cf7 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -392,11 +392,10 @@ CFLAGS_fortify_kunit.o += $(call cc-disable-warning, stringop-truncation)
 CFLAGS_fortify_kunit.o += $(DISABLE_STRUCTLEAK_PLUGIN)
 obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
 obj-$(CONFIG_CRC_KUNIT_TEST) += crc_kunit.o
 obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o
 obj-$(CONFIG_USERCOPY_KUNIT_TEST) += usercopy_kunit.o
-obj-$(CONFIG_CRC16_KUNIT_TEST) += crc16_kunit.o
 
 obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o
 
 obj-$(CONFIG_FIRMWARE_TABLE) += fw_table.o
 
diff --git a/lib/crc16_kunit.c b/lib/crc16_kunit.c
deleted file mode 100644
index 0918c98a96d2..000000000000
--- a/lib/crc16_kunit.c
+++ /dev/null
@@ -1,155 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * KUnits tests for CRC16.
- *
- * Copyright (C) 2024, LKCAMP
- * Author: Vinicius Peixoto <[email-masked]>
- * Author: Fabricio Gasperin <[email-masked]>
- * Author: Enzo Bertoloti <[email-masked]>
- */
-#include <kunit/test.h>
-#include <linux/crc16.h>
-#include <linux/prandom.h>
-
-#define CRC16_KUNIT_DATA_SIZE 4096
-#define CRC16_KUNIT_TEST_SIZE 100
-#define CRC16_KUNIT_SEED 0x12345678
-
-/**
- * struct crc16_test - CRC16 test data
- * @crc: initial input value to CRC16
- * @start: Start index within the data buffer
- * @length: Length of the data
- */
-static struct crc16_test {
-	u16 crc;
-	u16 start;
-	u16 length;
-} tests[CRC16_KUNIT_TEST_SIZE];
-
-u8 data[CRC16_KUNIT_DATA_SIZE];
-
-
-/* Naive implementation of CRC16 for validation purposes */
-static inline u16 _crc16_naive_byte(u16 crc, u8 data)
-{
-	u8 i = 0;
-
-	crc ^= (u16) data;
-	for (i = 0; i < 8; i++) {
-		if (crc & 0x01)
-			crc = (crc >> 1) ^ 0xa001;
-		else
-			crc = crc >> 1;
-	}
-
-	return crc;
-}
-
-
-static inline u16 _crc16_naive(u16 crc, u8 *buffer, size_t len)
-{
-	while (len--)
-		crc = _crc16_naive_byte(crc, *buffer++);
-	return crc;
-}
-
-
-/* Small helper for generating pseudorandom 16-bit data */
-static inline u16 _rand16(void)
-{
-	static u32 rand = CRC16_KUNIT_SEED;
-
-	rand = next_pseudo_random32(rand);
-	return rand & 0xFFFF;
-}
-
-
-static int crc16_init_test_data(struct kunit_suite *suite)
-{
-	size_t i;
-
-	/* Fill the data buffer with random bytes */
-	for (i = 0; i < CRC16_KUNIT_DATA_SIZE; i++)
-		data[i] = _rand16() & 0xFF;
-
-	/* Generate random test data while ensuring the random
-	 * start + length values won't overflow the 4096-byte
-	 * buffer (0x7FF * 2 = 0xFFE < 0x1000)
-	 */
-	for (size_t i = 0; i < CRC16_KUNIT_TEST_SIZE; i++) {
-		tests[i].crc = _rand16();
-		tests[i].start = _rand16() & 0x7FF;
-		tests[i].length = _rand16() & 0x7FF;
-	}
-
-	return 0;
-}
-
-static void crc16_test_empty(struct kunit *test)
-{
-	u16 crc;
-
-	/* The result for empty data should be the same as the
-	 * initial crc
-	 */
-	crc = crc16(0x00, data, 0);
-	KUNIT_EXPECT_EQ(test, crc, 0);
-	crc = crc16(0xFF, data, 0);
-	KUNIT_EXPECT_EQ(test, crc, 0xFF);
-}
-
-static void crc16_test_correctness(struct kunit *test)
-{
-	size_t i;
-	u16 crc, crc_naive;
-
-	for (i = 0; i < CRC16_KUNIT_TEST_SIZE; i++) {
-		/* Compare results with the naive crc16 implementation */
-		crc = crc16(tests[i].crc, data + tests[i].start,
-			    tests[i].length);
-		crc_naive = _crc16_naive(tests[i].crc, data + tests[i].start,
-					 tests[i].length);
-		KUNIT_EXPECT_EQ(test, crc, crc_naive);
-	}
-}
-
-
-static void crc16_test_combine(struct kunit *test)
-{
-	size_t i, j;
-	u16 crc, crc_naive;
-
-	/* Make sure that combining two consecutive crc16 calculations
-	 * yields the same result as calculating the crc16 for the whole thing
-	 */
-	for (i = 0; i < CRC16_KUNIT_TEST_SIZE; i++) {
-		crc_naive = crc16(tests[i].crc, data + tests[i].start, tests[i].length);
-		for (j = 0; j < tests[i].length; j++) {
-			crc = crc16(tests[i].crc, data + tests[i].start, j);
-			crc = crc16(crc, data + tests[i].start + j, tests[i].length - j);
-			KUNIT_EXPECT_EQ(test, crc, crc_naive);
-		}
-	}
-}
-
-
-static struct kunit_case crc16_test_cases[] = {
-	KUNIT_CASE(crc16_test_empty),
-	KUNIT_CASE(crc16_test_combine),
-	KUNIT_CASE(crc16_test_correctness),
-	{},
-};
-
-static struct kunit_suite crc16_test_suite = {
-	.name = "crc16",
-	.test_cases = crc16_test_cases,
-	.suite_init = crc16_init_test_data,
-};
-kunit_test_suite(crc16_test_suite);
-
-MODULE_AUTHOR("Fabricio Gasperin <[email-masked]>");
-MODULE_AUTHOR("Vinicius Peixoto <[email-masked]>");
-MODULE_AUTHOR("Enzo Bertoloti <[email-masked]>");
-MODULE_DESCRIPTION("Unit tests for crc16");
-MODULE_LICENSE("GPL");
-- 
2.47.1