lib/crc: tests: Make crc_kunit test only the enabled CRC variants

Like commit 4478e8e ("lib/crypto: tests: Depend on library options
rather than selecting them") did with the crypto library tests, make
crc_kunit depend on the code it tests rather than selecting it.  This
follows the standard convention for KUnit and fixes an issue where
enabling KUNIT_ALL_TESTS enabled non-test code.

crc_kunit does differ from the crypto library tests in that it
consolidates the tests for multiple CRC variants, with 5 kconfig
options, into one KUnit suite.  Since depending on *all* of these
kconfig options would greatly restrict the ability to enable crc_kunit,
instead just depend on *any* of these options.  Update crc_kunit
accordingly to test only the reachable code.

Alternatively we could split crc_kunit into 5 test suites.  But keeping
it as one is simpler for now.

Fixes: e47d9b1 ("lib/crc_kunit.c: add KUnit test suite for CRC library functions")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20260306033557.250499-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

Author: Eric Biggers

lib/crc/Kconfig

@@ -99,13 +99,8 @@ config CRC_OPTIMIZATIONS
 
 config CRC_KUNIT_TEST
 	tristate "KUnit tests for CRC functions" if !KUNIT_ALL_TESTS
-	depends on KUNIT
+	depends on KUNIT && (CRC7 || CRC16 || CRC_T10DIF || CRC32 || CRC64)
 	default KUNIT_ALL_TESTS
-	select CRC7
-	select CRC16
-	select CRC_T10DIF
-	select CRC32
-	select CRC64
 	help
 	  Unit tests for the CRC library functions.
 

lib/crc/tests/crc_kunit.c

@@ -268,8 +268,7 @@ crc_benchmark(struct kunit *test,
 	}
 }
 
-/* crc7_be */
-
+#if IS_REACHABLE(CONFIG_CRC7)
 static u64 crc7_be_wrapper(u64 crc, const u8 *p, size_t len)
 {
 	/*
@@ -294,9 +293,9 @@ static void crc7_be_benchmark(struct kunit *test)
 {
 	crc_benchmark(test, crc7_be_wrapper);
 }
+#endif /* CONFIG_CRC7 */
 
-/* crc16 */
-
+#if IS_REACHABLE(CONFIG_CRC16)
 static u64 crc16_wrapper(u64 crc, const u8 *p, size_t len)
 {
 	return crc16(crc, p, len);
@@ -318,9 +317,9 @@ static void crc16_benchmark(struct kunit *test)
 {
 	crc_benchmark(test, crc16_wrapper);
 }
+#endif /* CONFIG_CRC16 */
 
-/* crc_t10dif */
-
+#if IS_REACHABLE(CONFIG_CRC_T10DIF)
 static u64 crc_t10dif_wrapper(u64 crc, const u8 *p, size_t len)
 {
 	return crc_t10dif_update(crc, p, len);
@@ -342,6 +341,9 @@ static void crc_t10dif_benchmark(struct kunit *test)
 {
 	crc_benchmark(test, crc_t10dif_wrapper);
 }
+#endif /* CONFIG_CRC_T10DIF */
+
+#if IS_REACHABLE(CONFIG_CRC32)
 
 /* crc32_le */
 
@@ -414,6 +416,9 @@ static void crc32c_benchmark(struct kunit *test)
 {
 	crc_benchmark(test, crc32c_wrapper);
 }
+#endif /* CONFIG_CRC32 */
+
+#if IS_REACHABLE(CONFIG_CRC64)
 
 /* crc64_be */
 
@@ -463,24 +468,35 @@ static void crc64_nvme_benchmark(struct kunit *test)
 {
 	crc_benchmark(test, crc64_nvme_wrapper);
 }
+#endif /* CONFIG_CRC64 */
 
 static struct kunit_case crc_test_cases[] = {
+#if IS_REACHABLE(CONFIG_CRC7)
 	KUNIT_CASE(crc7_be_test),
 	KUNIT_CASE(crc7_be_benchmark),
+#endif
+#if IS_REACHABLE(CONFIG_CRC16)
 	KUNIT_CASE(crc16_test),
 	KUNIT_CASE(crc16_benchmark),
+#endif
+#if IS_REACHABLE(CONFIG_CRC_T10DIF)
 	KUNIT_CASE(crc_t10dif_test),
 	KUNIT_CASE(crc_t10dif_benchmark),
+#endif
+#if IS_REACHABLE(CONFIG_CRC32)
 	KUNIT_CASE(crc32_le_test),
 	KUNIT_CASE(crc32_le_benchmark),
 	KUNIT_CASE(crc32_be_test),
 	KUNIT_CASE(crc32_be_benchmark),
 	KUNIT_CASE(crc32c_test),
 	KUNIT_CASE(crc32c_benchmark),
+#endif
+#if IS_REACHABLE(CONFIG_CRC64)
 	KUNIT_CASE(crc64_be_test),
 	KUNIT_CASE(crc64_be_benchmark),
 	KUNIT_CASE(crc64_nvme_test),
 	KUNIT_CASE(crc64_nvme_benchmark),
+#endif
 	{},
 };