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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 B8F77C11D32 for ; Mon, 24 Feb 2020 18:22:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9D41220838 for ; Mon, 24 Feb 2020 18:22:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727968AbgBXSWE (ORCPT ); Mon, 24 Feb 2020 13:22:04 -0500 Received: from mga17.intel.com ([192.55.52.151]:6019 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727939AbgBXSWD (ORCPT ); Mon, 24 Feb 2020 13:22:03 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Feb 2020 10:22:02 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,481,1574150400"; d="scan'208";a="284426587" Received: from araj-mobl1.jf.intel.com ([10.24.11.16]) by FMSMGA003.fm.intel.com with ESMTP; 24 Feb 2020 10:22:02 -0800 Date: Mon, 24 Feb 2020 10:22:02 -0800 From: "Raj, Ashok" To: Zhangfei Gao Cc: Greg Kroah-Hartman , Arnd Bergmann , Herbert Xu , jonathan.cameron@huawei.com, dave.jiang@intel.com, grant.likely@arm.com, jean-philippe , Jerome Glisse , ilias.apalodimas@linaro.org, francois.ozog@linaro.org, kenneth-lee-2012@foxmail.com, Wangzhou , "haojian . zhuang" , guodong.xu@linaro.org, linux-accelerators@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, iommu@lists.linux-foundation.org, Kenneth Lee , Zaibo Xu , Ashok Raj Subject: Re: [PATCH v12 2/4] uacce: add uacce driver Message-ID: <20200224182201.GA22668@araj-mobl1.jf.intel.com> References: <1579097568-17542-1-git-send-email-zhangfei.gao@linaro.org> <1579097568-17542-3-git-send-email-zhangfei.gao@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1579097568-17542-3-git-send-email-zhangfei.gao@linaro.org> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Kenneth, sorry for waking up late on this patchset. On Wed, Jan 15, 2020 at 10:12:46PM +0800, Zhangfei Gao wrote: [... trimmed] > + > +static int uacce_fops_open(struct inode *inode, struct file *filep) > +{ > + struct uacce_mm *uacce_mm = NULL; > + struct uacce_device *uacce; > + struct uacce_queue *q; > + int ret = 0; > + > + uacce = xa_load(&uacce_xa, iminor(inode)); > + if (!uacce) > + return -ENODEV; > + > + q = kzalloc(sizeof(struct uacce_queue), GFP_KERNEL); > + if (!q) > + return -ENOMEM; > + > + mutex_lock(&uacce->mm_lock); > + uacce_mm = uacce_mm_get(uacce, q, current->mm); I think having this at open time is a bit unnatural. Since when a process does fork, we do not inherit the PASID. Although it inherits the fd but cannot use the mmaped address in the child. If you move this to the mmap time, its more natural. The child could do a mmap() get a new PASID + mmio space to work with the hardware. > + mutex_unlock(&uacce->mm_lock); > + if (!uacce_mm) { > + ret = -ENOMEM; > + goto out_with_mem; > + } > +