[PATCH] selftests/mm: Fix loss of information warnings

From: Siddarth G
Date: Fri Mar 28 2025 - 18:01:54 EST


Cppcheck reported a style warning:
int result is assigned to long long variable. If the variable is long long
to avoid loss of information, then you have loss of information.

Changing the type of page_size from 'unsigned int' to 'unsigned long long'
was considered. But that might cause new conversion issues in other
parts of the code where calculations involving 'page_size' are assigned
to int variables. So we approach by appending ULL suffixes

Reported-by: David Binderman <dcb314@xxxxxxxxxxx>
Closes: https://lore.kernel.org/all/AS8PR02MB10217315060BBFDB21F19643E9CA62@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
Signed-off-by: Siddarth G <siddarthsgml@xxxxxxxxx>
---
tools/testing/selftests/mm/pagemap_ioctl.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c b/tools/testing/selftests/mm/pagemap_ioctl.c
index 57b4bba2b45f..f3b12402ca89 100644
--- a/tools/testing/selftests/mm/pagemap_ioctl.c
+++ b/tools/testing/selftests/mm/pagemap_ioctl.c
@@ -244,7 +244,7 @@ int sanity_tests_sd(void)
long walk_end;

vec_size = num_pages/2;
- mem_size = num_pages * page_size;
+ mem_size = num_pages * (long long)page_size;

vec = malloc(sizeof(struct page_region) * vec_size);
if (!vec)
@@ -432,7 +432,7 @@ int sanity_tests_sd(void)
free(vec2);

/* 8. Smaller vec */
- mem_size = 1050 * page_size;
+ mem_size = 1050ULL * page_size;
vec_size = mem_size/(page_size*2);

vec = malloc(sizeof(struct page_region) * vec_size);
@@ -487,7 +487,7 @@ int sanity_tests_sd(void)
total_pages = 0;

/* 9. Smaller vec */
- mem_size = 10000 * page_size;
+ mem_size = 10000ULL * page_size;
vec_size = 50;

vec = malloc(sizeof(struct page_region) * vec_size);
@@ -1058,7 +1058,7 @@ int sanity_tests(void)
char *tmp_buf;

/* 1. wrong operation */
- mem_size = 10 * page_size;
+ mem_size = 10ULL * page_size;
vec_size = mem_size / page_size;

vec = malloc(sizeof(struct page_region) * vec_size);
@@ -1507,7 +1507,7 @@ int main(int __attribute__((unused)) argc, char *argv[])
sanity_tests_sd();

/* 2. Normal page testing */
- mem_size = 10 * page_size;
+ mem_size = 10ULL * page_size;
mem = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
if (mem == MAP_FAILED)
ksft_exit_fail_msg("error nomem\n");
@@ -1520,7 +1520,7 @@ int main(int __attribute__((unused)) argc, char *argv[])
munmap(mem, mem_size);

/* 3. Large page testing */
- mem_size = 512 * 10 * page_size;
+ mem_size = 512ULL * 10 * page_size;
mem = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
if (mem == MAP_FAILED)
ksft_exit_fail_msg("error nomem\n");
--
2.43.0