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

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Message-Id: <20220308105918.615575-3-pbonzini@redhat.com>
Date:   Tue,  8 Mar 2022 05:59:17 -0500
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Michael Ellerman <mpe@...erman.id.au>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Dennis Zhou <dennis@...nel.org>, Tejun Heo <tj@...nel.org>,
        Christoph Lameter <cl@...ux.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Michal Hocko <mhocko@...nel.org>,
        Vladimir Davydov <vdavydov.dev@...il.com>, linux-mm@...ck.org,
        cgroups@...r.kernel.org
Subject: [PATCH 2/3] mm: use vmalloc_array and vcalloc for array allocations

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@...ck.org
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 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