io_uring: clean up io_prep_rw_setup()

Remove unnecessary call to iov_iter_save_state() in io_prep_rw_setup()
as io_import_iovec() already does this. Then the result from
io_import_iovec() can be returned directly.

Signed-off-by: David Wei <dw@davidwei.uk>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Tested-by: Li Zetao <lizetao1@huawei.com>
Link: https://lore.kernel.org/r/20241207004144.783631-1-dw@davidwei.uk
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: spikeh

io_uring/rw.c

@@ -240,7 +240,6 @@ static int io_rw_alloc_async(struct io_kiocb *req)
 static int io_prep_rw_setup(struct io_kiocb *req, int ddir, bool do_import)
 {
 	struct io_async_rw *rw;
-	int ret;
 
 	if (io_rw_alloc_async(req))
 		return -ENOMEM;
@@ -249,12 +248,7 @@ static int io_prep_rw_setup(struct io_kiocb *req, int ddir, bool do_import)
 		return 0;
 
 	rw = req->async_data;
-	ret = io_import_iovec(ddir, req, rw, 0);
-	if (unlikely(ret < 0))
-		return ret;
-
-	iov_iter_save_state(&rw->iter, &rw->iter_state);
-	return 0;
+	return io_import_iovec(ddir, req, rw, 0);
 }
 
 static inline void io_meta_save_state(struct io_async_rw *io)