block: bio: Use struct_size() in kmalloc()

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/bio.c b/block/bio.c
index a7366c02c9b57fb089a7d64c3bf7dc73dbb486d6..fb5533416fa6708008776d0d4b89c544c42d30ab 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -444,9 +444,7 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, unsigned int nr_iovecs,
                if (nr_iovecs > UIO_MAXIOV)
                        return NULL;
 
-               p = kmalloc(sizeof(struct bio) +
-                           nr_iovecs * sizeof(struct bio_vec),
-                           gfp_mask);
+               p = kmalloc(struct_size(bio, bi_inline_vecs, nr_iovecs), gfp_mask);
                front_pad = 0;
                inline_vecs = nr_iovecs;
        } else {