ratelimiter: use kvcalloc() instead of kvzalloc()

Use 2-factor argument form kvcalloc() instead of kvzalloc().

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

Author: GustavoARSilva

src/compat/compat.h

@@ -515,6 +515,28 @@ static inline void __compat_kvfree(const void *addr)
 #define kvfree __compat_kvfree
 #endif
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 12, 0)
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+static inline void *__compat_kvmalloc_array(size_t n, size_t size, gfp_t flags)
+{
+	if (n != 0 && SIZE_MAX / n < size)
+		return NULL;
+	return kvmalloc(n * size, flags);
+}
+#define kvmalloc_array __compat_kvmalloc_array
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 18, 0)
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+static inline void *__compat_kvcalloc(size_t n, size_t size, gfp_t flags)
+{
+        return kvmalloc_array(n, size, flags | __GFP_ZERO);
+}
+#define kvcalloc __compat_kvcalloc
+#endif
+
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 11, 9)
 #include <linux/netdevice.h>
 #define priv_destructor destructor

src/ratelimiter.c

@@ -188,12 +188,12 @@ int wg_ratelimiter_init(void)
 			(1U << 14) / sizeof(struct hlist_head)));
 	max_entries = table_size * 8;
 
-	table_v4 = kvzalloc(table_size * sizeof(*table_v4), GFP_KERNEL);
+	table_v4 = kvcalloc(table_size, sizeof(*table_v4), GFP_KERNEL);
 	if (unlikely(!table_v4))
 		goto err_kmemcache;
 
 #if IS_ENABLED(CONFIG_IPV6)
-	table_v6 = kvzalloc(table_size * sizeof(*table_v6), GFP_KERNEL);
+	table_v6 = kvcalloc(table_size, sizeof(*table_v6), GFP_KERNEL);
 	if (unlikely(!table_v6)) {
 		kvfree(table_v4);
 		goto err_kmemcache;