blk-iocost: Use struct_size() in kzalloc_node()

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

This code was detected with the help of Coccinelle and, audited and
fixed manually.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 8ac4aad66ebc3783e009c51282eb52aa3edaa15d..cea5ee9be63999a2d340dadb8b61e76ba8ba2fda 100644 (file)
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -2045,8 +2045,7 @@ static struct blkg_policy_data *ioc_pd_alloc(gfp_t gfp, struct request_queue *q,
        int levels = blkcg->css.cgroup->level + 1;
        struct ioc_gq *iocg;
 
-       iocg = kzalloc_node(sizeof(*iocg) + levels * sizeof(iocg->ancestors[0]),
-                           gfp, q->node);
+       iocg = kzalloc_node(struct_size(iocg, ancestors, levels), gfp, q->node);
        if (!iocg)
                return NULL;