Use ERR_CAST() instead of ERR_PTR(PTR_ERR()).
This makes it more readable and also fix this warning detected by
err_cast.cocci:
./fs/io_uring.c: WARNING: 3208: 11-18: ERR_CAST can be used with buf
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Changcheng Deng <deng.changcheng@zte.com.cn>
Link: https://lore.kernel.org/r/20211020084948.1038420-1-deng.changcheng@zte.com.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
 
                if (req->flags & REQ_F_BUFFER_SELECT) {
                        buf = io_rw_buffer_select(req, &sqe_len, issue_flags);
                        if (IS_ERR(buf))
-                               return ERR_PTR(PTR_ERR(buf));
+                               return ERR_CAST(buf);
                        req->rw.len = sqe_len;
                }