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238 lines
6.5 KiB
238 lines
6.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Test cases for <linux/hash.h> and <linux/stringhash.h> |
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* This just verifies that various ways of computing a hash |
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* produce the same thing and, for cases where a k-bit hash |
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* value is requested, is of the requested size. |
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* |
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* We fill a buffer with a 255-byte null-terminated string, |
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* and use both full_name_hash() and hashlen_string() to hash the |
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* substrings from i to j, where 0 <= i < j < 256. |
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* |
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* The returned values are used to check that __hash_32() and |
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* __hash_32_generic() compute the same thing. Likewise hash_32() |
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* and hash_64(). |
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*/ |
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#include <linux/compiler.h> |
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#include <linux/types.h> |
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#include <linux/module.h> |
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#include <linux/hash.h> |
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#include <linux/stringhash.h> |
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#include <kunit/test.h> |
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/* 32-bit XORSHIFT generator. Seed must not be zero. */ |
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static u32 __attribute_const__ |
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xorshift(u32 seed) |
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{ |
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seed ^= seed << 13; |
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seed ^= seed >> 17; |
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seed ^= seed << 5; |
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return seed; |
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} |
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/* Given a non-zero x, returns a non-zero byte. */ |
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static u8 __attribute_const__ |
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mod255(u32 x) |
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{ |
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x = (x & 0xffff) + (x >> 16); /* 1 <= x <= 0x1fffe */ |
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x = (x & 0xff) + (x >> 8); /* 1 <= x <= 0x2fd */ |
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x = (x & 0xff) + (x >> 8); /* 1 <= x <= 0x100 */ |
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x = (x & 0xff) + (x >> 8); /* 1 <= x <= 0xff */ |
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return x; |
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} |
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/* Fill the buffer with non-zero bytes. */ |
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static void fill_buf(char *buf, size_t len, u32 seed) |
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{ |
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size_t i; |
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for (i = 0; i < len; i++) { |
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seed = xorshift(seed); |
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buf[i] = mod255(seed); |
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} |
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} |
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/* Holds most testing variables for the int test. */ |
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struct test_hash_params { |
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/* Pointer to integer to be hashed. */ |
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unsigned long long *h64; |
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/* Low 32-bits of integer to be hashed. */ |
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u32 h0; |
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/* Arch-specific hash result. */ |
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u32 h1; |
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/* Generic hash result. */ |
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u32 h2; |
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/* ORed hashes of given size (in bits). */ |
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u32 (*hash_or)[33]; |
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}; |
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#ifdef HAVE_ARCH__HASH_32 |
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static void |
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test_int__hash_32(struct kunit *test, struct test_hash_params *params) |
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{ |
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params->hash_or[1][0] |= params->h2 = __hash_32_generic(params->h0); |
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#if HAVE_ARCH__HASH_32 == 1 |
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KUNIT_EXPECT_EQ_MSG(test, params->h1, params->h2, |
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"__hash_32(%#x) = %#x != __hash_32_generic() = %#x", |
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params->h0, params->h1, params->h2); |
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#endif |
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} |
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#endif |
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#ifdef HAVE_ARCH_HASH_64 |
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static void |
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test_int_hash_64(struct kunit *test, struct test_hash_params *params, u32 const *m, int *k) |
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{ |
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params->h2 = hash_64_generic(*params->h64, *k); |
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#if HAVE_ARCH_HASH_64 == 1 |
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KUNIT_EXPECT_EQ_MSG(test, params->h1, params->h2, |
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"hash_64(%#llx, %d) = %#x != hash_64_generic() = %#x", |
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*params->h64, *k, params->h1, params->h2); |
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#else |
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KUNIT_EXPECT_LE_MSG(test, params->h1, params->h2, |
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"hash_64_generic(%#llx, %d) = %#x > %#x", |
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*params->h64, *k, params->h1, *m); |
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#endif |
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} |
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#endif |
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/* |
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* Test the various integer hash functions. h64 (or its low-order bits) |
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* is the integer to hash. hash_or accumulates the OR of the hash values, |
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* which are later checked to see that they cover all the requested bits. |
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* |
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* Because these functions (as opposed to the string hashes) are all |
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* inline, the code being tested is actually in the module, and you can |
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* recompile and re-test the module without rebooting. |
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*/ |
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static void |
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test_int_hash(struct kunit *test, unsigned long long h64, u32 hash_or[2][33]) |
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{ |
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int k; |
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struct test_hash_params params = { &h64, (u32)h64, 0, 0, hash_or }; |
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/* Test __hash32 */ |
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hash_or[0][0] |= params.h1 = __hash_32(params.h0); |
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#ifdef HAVE_ARCH__HASH_32 |
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test_int__hash_32(test, ¶ms); |
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#endif |
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/* Test k = 1..32 bits */ |
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for (k = 1; k <= 32; k++) { |
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u32 const m = ((u32)2 << (k-1)) - 1; /* Low k bits set */ |
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/* Test hash_32 */ |
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hash_or[0][k] |= params.h1 = hash_32(params.h0, k); |
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KUNIT_EXPECT_LE_MSG(test, params.h1, m, |
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"hash_32(%#x, %d) = %#x > %#x", |
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params.h0, k, params.h1, m); |
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/* Test hash_64 */ |
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hash_or[1][k] |= params.h1 = hash_64(h64, k); |
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KUNIT_EXPECT_LE_MSG(test, params.h1, m, |
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"hash_64(%#llx, %d) = %#x > %#x", |
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h64, k, params.h1, m); |
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#ifdef HAVE_ARCH_HASH_64 |
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test_int_hash_64(test, ¶ms, &m, &k); |
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#endif |
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} |
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} |
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#define SIZE 256 /* Run time is cubic in SIZE */ |
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static void test_string_or(struct kunit *test) |
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{ |
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char buf[SIZE+1]; |
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u32 string_or = 0; |
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int i, j; |
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fill_buf(buf, SIZE, 1); |
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/* Test every possible non-empty substring in the buffer. */ |
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for (j = SIZE; j > 0; --j) { |
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buf[j] = '\0'; |
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for (i = 0; i <= j; i++) { |
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u32 h0 = full_name_hash(buf+i, buf+i, j-i); |
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string_or |= h0; |
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} /* i */ |
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} /* j */ |
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/* The OR of all the hash values should cover all the bits */ |
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KUNIT_EXPECT_EQ_MSG(test, string_or, -1u, |
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"OR of all string hash results = %#x != %#x", |
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string_or, -1u); |
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} |
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static void test_hash_or(struct kunit *test) |
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{ |
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char buf[SIZE+1]; |
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u32 hash_or[2][33] = { { 0, } }; |
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unsigned long long h64 = 0; |
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int i, j; |
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fill_buf(buf, SIZE, 1); |
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/* Test every possible non-empty substring in the buffer. */ |
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for (j = SIZE; j > 0; --j) { |
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buf[j] = '\0'; |
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for (i = 0; i <= j; i++) { |
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u64 hashlen = hashlen_string(buf+i, buf+i); |
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u32 h0 = full_name_hash(buf+i, buf+i, j-i); |
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/* Check that hashlen_string gets the length right */ |
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KUNIT_EXPECT_EQ_MSG(test, hashlen_len(hashlen), j-i, |
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"hashlen_string(%d..%d) returned length %u, expected %d", |
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i, j, hashlen_len(hashlen), j-i); |
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/* Check that the hashes match */ |
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KUNIT_EXPECT_EQ_MSG(test, hashlen_hash(hashlen), h0, |
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"hashlen_string(%d..%d) = %08x != full_name_hash() = %08x", |
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i, j, hashlen_hash(hashlen), h0); |
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h64 = h64 << 32 | h0; /* For use with hash_64 */ |
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test_int_hash(test, h64, hash_or); |
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} /* i */ |
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} /* j */ |
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KUNIT_EXPECT_EQ_MSG(test, hash_or[0][0], -1u, |
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"OR of all __hash_32 results = %#x != %#x", |
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hash_or[0][0], -1u); |
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#ifdef HAVE_ARCH__HASH_32 |
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#if HAVE_ARCH__HASH_32 != 1 /* Test is pointless if results match */ |
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KUNIT_EXPECT_EQ_MSG(test, hash_or[1][0], -1u, |
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"OR of all __hash_32_generic results = %#x != %#x", |
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hash_or[1][0], -1u); |
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#endif |
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#endif |
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/* Likewise for all the i-bit hash values */ |
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for (i = 1; i <= 32; i++) { |
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u32 const m = ((u32)2 << (i-1)) - 1; /* Low i bits set */ |
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KUNIT_EXPECT_EQ_MSG(test, hash_or[0][i], m, |
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"OR of all hash_32(%d) results = %#x (%#x expected)", |
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i, hash_or[0][i], m); |
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KUNIT_EXPECT_EQ_MSG(test, hash_or[1][i], m, |
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"OR of all hash_64(%d) results = %#x (%#x expected)", |
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i, hash_or[1][i], m); |
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} |
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} |
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static struct kunit_case hash_test_cases[] __refdata = { |
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KUNIT_CASE(test_string_or), |
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KUNIT_CASE(test_hash_or), |
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{} |
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}; |
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static struct kunit_suite hash_test_suite = { |
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.name = "hash", |
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.test_cases = hash_test_cases, |
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}; |
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kunit_test_suite(hash_test_suite); |
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MODULE_LICENSE("GPL");
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