io_uring: move io_uring_rsrc_update2 validation

[ Upstream commit 565c5e6 ]

Move validation to be more consistently straight after
copy_from_user. This is already done in io_register_rsrc_update and so
this removes that redundant check.

Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220412163042.2788062-2-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

fs/io_uring.c

@@ -10784,8 +10784,6 @@ static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
 	__u32 tmp;
 	int err;
 
-	if (up->resv)
-		return -EINVAL;
 	if (check_add_overflow(up->offset, nr_args, &tmp))
 		return -EOVERFLOW;
 	err = io_rsrc_node_switch_start(ctx);
@@ -10811,6 +10809,8 @@ static int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
 	memset(&up, 0, sizeof(up));
 	if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
 		return -EFAULT;
+	if (up.resv)
+		return -EINVAL;
 	return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
 }