[PATCH 2/3] mm: use vmalloc_array and vcalloc for array allocations

From: Paolo Bonzini
Date: Tue Mar 08 2022 - 05:59:39 EST


Instead of using array_size or just a multiply, use a function that
takes care of both the multiplication and the overflow checks.

Cc: linux-mm@xxxxxxxxx
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
mm/percpu-stats.c | 2 +-
mm/swap_cgroup.c | 4 +---
2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/mm/percpu-stats.c b/mm/percpu-stats.c
index c6bd092ff7a3..e71651cda2de 100644
--- a/mm/percpu-stats.c
+++ b/mm/percpu-stats.c
@@ -144,7 +144,7 @@ static int percpu_stats_show(struct seq_file *m, void *v)
spin_unlock_irq(&pcpu_lock);

/* there can be at most this many free and allocated fragments */
- buffer = vmalloc(array_size(sizeof(int), (2 * max_nr_alloc + 1)));
+ buffer = vmalloc_array(2 * max_nr_alloc + 1, sizeof(int));
if (!buffer)
return -ENOMEM;

diff --git a/mm/swap_cgroup.c b/mm/swap_cgroup.c
index 7f34343c075a..5a9442979a18 100644
--- a/mm/swap_cgroup.c
+++ b/mm/swap_cgroup.c
@@ -167,14 +167,12 @@ unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
int swap_cgroup_swapon(int type, unsigned long max_pages)
{
void *array;
- unsigned long array_size;
unsigned long length;
struct swap_cgroup_ctrl *ctrl;

length = DIV_ROUND_UP(max_pages, SC_PER_PAGE);
- array_size = length * sizeof(void *);

- array = vzalloc(array_size);
+ array = vcalloc(length, sizeof(void *));
if (!array)
goto nomem;

--
2.31.1