diff --git a/tools/testing/selftests/mm/mremap_test.c b/tools/testing/selftests/mm/mremap_test.c index 308576437228..131d9d6db867 100644 --- a/tools/testing/selftests/mm/mremap_test.c +++ b/tools/testing/selftests/mm/mremap_test.c @@ -76,27 +76,6 @@ enum { .expect_failure = should_fail \ } -/* compute square root using binary search */ -static unsigned long get_sqrt(unsigned long val) -{ - unsigned long low = 1; - - /* assuming rand_size is less than 1TB */ - unsigned long high = (1UL << 20); - - while (low <= high) { - unsigned long mid = low + (high - low) / 2; - unsigned long temp = mid * mid; - - if (temp == val) - return mid; - if (temp < val) - low = mid + 1; - high = mid - 1; - } - return low; -} - /* * Returns false if the requested remap region overlaps with an * existing mapping (e.g text, stack) else returns true. @@ -995,11 +974,9 @@ static long long remap_region(struct config c, unsigned int threshold_mb, char *rand_addr) { void *addr, *tmp_addr, *src_addr, *dest_addr, *dest_preamble_addr = NULL; - unsigned long long t, d; struct timespec t_start = {0, 0}, t_end = {0, 0}; long long start_ns, end_ns, align_mask, ret, offset; unsigned long long threshold; - unsigned long num_chunks; if (threshold_mb == VALIDATION_NO_THRESHOLD) threshold = c.region_size; @@ -1068,87 +1045,21 @@ static long long remap_region(struct config c, unsigned int threshold_mb, goto clean_up_dest_preamble; } - /* - * Verify byte pattern after remapping. Employ an algorithm with a - * square root time complexity in threshold: divide the range into - * chunks, if memcmp() returns non-zero, only then perform an - * iteration in that chunk to find the mismatch index. - */ - num_chunks = get_sqrt(threshold); - for (unsigned long i = 0; i < num_chunks; ++i) { - size_t chunk_size = threshold / num_chunks; - unsigned long shift = i * chunk_size; - - if (!memcmp(dest_addr + shift, rand_addr + shift, chunk_size)) - continue; - - /* brute force iteration only over mismatch segment */ - for (t = shift; t < shift + chunk_size; ++t) { - if (((char *) dest_addr)[t] != rand_addr[t]) { - ksft_print_msg("Data after remap doesn't match at offset %llu\n", - t); - ksft_print_msg("Expected: %#x\t Got: %#x\n", rand_addr[t] & 0xff, - ((char *) dest_addr)[t] & 0xff); - ret = -1; - goto clean_up_dest; - } - } - } - - /* - * if threshold is not divisible by num_chunks, then check the - * last chunk - */ - for (t = num_chunks * (threshold / num_chunks); t < threshold; ++t) { - if (((char *) dest_addr)[t] != rand_addr[t]) { - ksft_print_msg("Data after remap doesn't match at offset %llu\n", - t); - ksft_print_msg("Expected: %#x\t Got: %#x\n", rand_addr[t] & 0xff, - ((char *) dest_addr)[t] & 0xff); - ret = -1; - goto clean_up_dest; - } + /* Verify byte pattern after remapping */ + if (memcmp(dest_addr, rand_addr, threshold)) { + ksft_print_msg("Data after remap doesn't match\n"); + ret = -1; + goto clean_up_dest; } /* Verify the dest preamble byte pattern after remapping */ - if (!c.dest_preamble_size) - goto no_preamble; - - num_chunks = get_sqrt(c.dest_preamble_size); - - for (unsigned long i = 0; i < num_chunks; ++i) { - size_t chunk_size = c.dest_preamble_size / num_chunks; - unsigned long shift = i * chunk_size; - - if (!memcmp(dest_preamble_addr + shift, rand_addr + shift, - chunk_size)) - continue; - - /* brute force iteration only over mismatched segment */ - for (d = shift; d < shift + chunk_size; ++d) { - if (((char *) dest_preamble_addr)[d] != rand_addr[d]) { - ksft_print_msg("Preamble data after remap doesn't match at offset %llu\n", - d); - ksft_print_msg("Expected: %#x\t Got: %#x\n", rand_addr[d] & 0xff, - ((char *) dest_preamble_addr)[d] & 0xff); - ret = -1; - goto clean_up_dest; - } - } + if (c.dest_preamble_size && + memcmp(dest_preamble_addr, rand_addr, c.dest_preamble_size)) { + ksft_print_msg("Preamble data after remap doesn't match\n"); + ret = -1; + goto clean_up_dest; } - for (d = num_chunks * (c.dest_preamble_size / num_chunks); d < c.dest_preamble_size; ++d) { - if (((char *) dest_preamble_addr)[d] != rand_addr[d]) { - ksft_print_msg("Preamble data after remap doesn't match at offset %llu\n", - d); - ksft_print_msg("Expected: %#x\t Got: %#x\n", rand_addr[d] & 0xff, - ((char *) dest_preamble_addr)[d] & 0xff); - ret = -1; - goto clean_up_dest; - } - } - -no_preamble: start_ns = t_start.tv_sec * NS_PER_SEC + t_start.tv_nsec; end_ns = t_end.tv_sec * NS_PER_SEC + t_end.tv_nsec; ret = end_ns - start_ns;