block/bio-integrity: use struct_size() in kmalloc()

Use the new struct_size() helper to keep code simple.
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/bio-integrity.c

@@ -43,8 +43,7 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
 	unsigned inline_vecs;
 
 	if (!bs || !mempool_initialized(&bs->bio_integrity_pool)) {
-		bip = kmalloc(sizeof(struct bio_integrity_payload) +
-			      sizeof(struct bio_vec) * nr_vecs, gfp_mask);
+		bip = kmalloc(struct_size(bip, bip_inline_vecs, nr_vecs), gfp_mask);
 		inline_vecs = nr_vecs;
 	} else {
 		bip = mempool_alloc(&bs->bio_integrity_pool, gfp_mask);