[PATCH v2 12/24] btrfs: zoned: use vmalloc_array and vcalloc

[Julia Lawall]

Use vmalloc_array and vcalloc to protect against
multiplication overflows.

The changes were done using the following Coccinelle
semantic patch:

// <smpl>
@initialize:ocaml@
@@

let rename alloc =
  match alloc with
    "vmalloc" -> "vmalloc_array"
  | "vzalloc" -> "vcalloc"
  | _ -> failwith "unknown"

@@
    size_t e1,e2;
    constant C1, C2;
    expression E1, E2, COUNT, x1, x2, x3;
    typedef u8;
    typedef __u8;
    type t = {u8,__u8,char,unsigned char};
    identifier alloc = {vmalloc,vzalloc};
    fresh identifier realloc = script:ocaml(alloc) { rename alloc };
@@

(
      alloc(x1*x2*x3)
|
      alloc(C1 * C2)
|
      alloc((sizeof(t)) * (COUNT), ...)
|
-     alloc((e1) * (e2))
+     realloc(e1, e2)
|
-     alloc((e1) * (COUNT))
+     realloc(COUNT, e1)
|
-     alloc((E1) * (E2))
+     realloc(E1, E2)
)
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxxx>

---
v2: Use vmalloc_array and vcalloc instead of array_size.
This also leaves a multiplication of a constant by a sizeof
as is.  Two patches are thus dropped from the series.

 fs/btrfs/zoned.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff -u -p a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -465,8 +465,8 @@ int btrfs_get_dev_zone_info(struct btrfs
 	 * use the cache.
 	 */
 	if (populate_cache && bdev_is_zoned(device->bdev)) {
-		zone_info->zone_cache = vzalloc(sizeof(struct blk_zone) *
-						zone_info->nr_zones);
+		zone_info->zone_cache = vcalloc(zone_info->nr_zones,
+						sizeof(struct blk_zone));
 		if (!zone_info->zone_cache) {
 			btrfs_err_in_rcu(device->fs_info,
 				"zoned: failed to allocate zone cache for %s",