fs/afs: use struct_size() in kzalloc()

As Gustavo said in other patches doing the same replace, we can now
use the new struct_size() helper to avoid leaving these open-coded and
prone to type mistake.

Signed-off-by: Zhengyuan Liu <[e-mail]>
Signed-off-by: David Howells <[e-mail]>

fs/afs/dir.c

···
 	if (nr_inline > (PAGE_SIZE - sizeof(*req)) / sizeof(struct page *))
 		nr_inline = 0;
 
-	req = kzalloc(sizeof(*req) + sizeof(struct page *) * nr_inline,
-		      GFP_KERNEL);
+	req = kzalloc(struct_size(req, array, nr_inline), GFP_KERNEL);
 	if (!req)
 		return ERR_PTR(-ENOMEM);
 

fs/afs/file.c

···
 		/* fall through */
 	default:
 	go_on:
-		req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *),
-			      GFP_KERNEL);
+		req = kzalloc(struct_size(req, array, 1), GFP_KERNEL);
 		if (!req)
 			goto enomem;
 
···
 		n++;
 	}
 
-	req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *) * n,
-		      GFP_NOFS);
+	req = kzalloc(struct_size(req, array, n), GFP_NOFS);
 	if (!req)
 		return -ENOMEM;
 

fs/afs/write.c

···
 		return 0;
 	}
 
-	req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *),
-		      GFP_KERNEL);
+	req = kzalloc(struct_size(req, array, 1), GFP_KERNEL);
 	if (!req)
 		return -ENOMEM;