From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23289C5519F for ; Wed, 18 Nov 2020 22:17:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 72CCD246E2 for ; Wed, 18 Nov 2020 22:17:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726092AbgKRWR2 (ORCPT ); Wed, 18 Nov 2020 17:17:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:43570 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726081AbgKRWR1 (ORCPT ); Wed, 18 Nov 2020 17:17:27 -0500 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 19404246DE; Wed, 18 Nov 2020 22:17:26 +0000 (UTC) Date: Wed, 18 Nov 2020 17:17:22 -0500 From: Steven Rostedt To: "Yordan Karadzhov (VMware)" Cc: linux-trace-devel@vger.kernel.org Subject: Re: [PATCH v4 06/20] kernel-shark: Add basic methods for Data streams Message-ID: <20201118171722.3b305816@oasis.local.home> In-Reply-To: <20201118145003.156542-7-y.karadz@gmail.com> References: <20201118145003.156542-1-y.karadz@gmail.com> <20201118145003.156542-7-y.karadz@gmail.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Wed, 18 Nov 2020 16:49:49 +0200 "Yordan Karadzhov (VMware)" wrote: > +/** > + * Bit mask (16-63) used when converting indexes to pointers and vise-versa. > + */ > +#define INVALID_STREAM_MASK (~((uint64_t) INDEX_MASK)) This wont work on a 32 bit machine, as pointers are 32 bits not 64. > + > +static int index_from_ptr(void *ptr) > +{ > + unsigned long index = (unsigned long) ptr; > + > + return (int) (index & INDEX_MASK); > +} > + > +static void *index_to_ptr(unsigned int index) > +{ > + unsigned long p; > + > + p = INVALID_STREAM_MASK | index; > + > + return (void *) p; > +} > + > +static bool kshark_is_valid_stream(void *ptr) > +{ > + unsigned long p = (unsigned long) ptr; > + bool v = !((p & ~INDEX_MASK) == INVALID_STREAM_MASK); On 32 bit, the above will always fail, because unsigned long is 32 bits (as is void *), but INVALID_STREAM_MASK is 64 bits. And the two could never equal each other. -- Steve > + > + return p && v; > +} > +