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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 45A1CC47247 for ; Thu, 30 Apr 2020 20:42:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 12557207DD for ; Thu, 30 Apr 2020 20:42:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 12557207DD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A507B8E0005; Thu, 30 Apr 2020 16:42:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9FFB38E0001; Thu, 30 Apr 2020 16:42:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 915998E0005; Thu, 30 Apr 2020 16:42:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0085.hostedemail.com [216.40.44.85]) by kanga.kvack.org (Postfix) with ESMTP id 77B278E0001 for ; Thu, 30 Apr 2020 16:42:42 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 381538248D7C for ; Thu, 30 Apr 2020 20:42:42 +0000 (UTC) X-FDA: 76765694964.28.smash20_34a09fa921261 X-HE-Tag: smash20_34a09fa921261 X-Filterd-Recvd-Size: 2742 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by imf29.hostedemail.com (Postfix) with ESMTP for ; Thu, 30 Apr 2020 20:42:41 +0000 (UTC) IronPort-SDR: mo3UyG9lCZ5bWdSNn5vDH/UXVTW9ukSeMI/htlq9hjBdwkxy2hNu01wfPJm8fJ57hKtI48yscO KCjx9lAWPpoA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Apr 2020 13:42:39 -0700 IronPort-SDR: M6oqOMPzyFoVqddYs7RXgFErbffJCDivKopljAfdVamHixYraY4H4gkBAqaneuwRMIgM/plR4C XjTmGyPtMWrw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,337,1583222400"; d="scan'208";a="433100232" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by orsmga005.jf.intel.com with ESMTP; 30 Apr 2020 13:42:39 -0700 Date: Thu, 30 Apr 2020 13:48:42 -0700 From: Jacob Pan To: Jean-Philippe Brucker Cc: iommu@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, joro@8bytes.org, catalin.marinas@arm.com, will@kernel.org, robin.murphy@arm.com, kevin.tian@intel.com, baolu.lu@linux.intel.com, Jonathan.Cameron@huawei.com, christian.koenig@amd.com, felix.kuehling@amd.com, zhangfei.gao@linaro.org, jgg@ziepe.ca, xuzaibo@huawei.com, fenghua.yu@intel.com, hch@infradead.org, jacob.jun.pan@linux.intel.com Subject: Re: [PATCH v6 02/25] iommu/ioasid: Add ioasid references Message-ID: <20200430134842.74e596b8@jacob-builder> In-Reply-To: <20200430113931.0fbf7a37@jacob-builder> References: <20200430143424.2787566-1-jean-philippe@linaro.org> <20200430143424.2787566-3-jean-philippe@linaro.org> <20200430113931.0fbf7a37@jacob-builder> Organization: OTC X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, 30 Apr 2020 11:39:31 -0700 Jacob Pan wrote: > > -void ioasid_free(ioasid_t ioasid) > > +bool ioasid_free(ioasid_t ioasid) > > { Sorry I missed this in the last reply. I think free needs to be unconditional since there is not a good way to fail it. Also can we have more symmetric APIs, seems we don't have ioasid_put() in this patchset. How about? ioasid_alloc() ioasid_free(); //drop reference, mark inactive, but not reclaimed if refcount is not zero. ioasid_get() // returns err if the ioasid is marked inactive by ioasid_free() ioasid_put();// drop reference, reclaim if refcount is 0. It is similar to get/put/alloc/free pids.