From patchwork Thu Jun 13 16:30:07 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 10992765 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C94FD14E5 for ; Thu, 13 Jun 2019 16:30:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B943C2022C for ; Thu, 13 Jun 2019 16:30:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AD56F23B24; Thu, 13 Jun 2019 16:30:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 50BEF20881 for ; Thu, 13 Jun 2019 16:30:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403770AbfFMQaP (ORCPT ); Thu, 13 Jun 2019 12:30:15 -0400 Received: from mga11.intel.com ([192.55.52.93]:57287 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730917AbfFMQaN (ORCPT ); Thu, 13 Jun 2019 12:30:13 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Jun 2019 09:30:13 -0700 X-ExtLoop1: 1 Received: from gengelha-mobl.ger.corp.intel.com (HELO localhost) ([10.249.32.179]) by orsmga006.jf.intel.com with ESMTP; 13 Jun 2019 09:30:10 -0700 From: Jarkko Sakkinen To: linux-sgx@vger.kernel.org Cc: luto@kernel.org, cedric.xing@intel.com, Jarkko Sakkinen Subject: [PATCH RFC] x86/sgx: Do not increase encl->refcount for VMAs Date: Thu, 13 Jun 2019 19:30:07 +0300 Message-Id: <20190613163008.4060-1-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Since the device file stays open up until all VMAs have been closed we do not need to increase encl->refcount for VMAs. sgx_open() will increase it once and sgx_release() will decrease at a point where the device file is not mapped. anymore. Signed-off-by: Jarkko Sakkinen --- Based on the commentary from Andy and Cedric. arch/x86/kernel/cpu/sgx/driver/main.c | 2 -- arch/x86/kernel/cpu/sgx/encl.c | 3 --- 2 files changed, 5 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/driver/main.c b/arch/x86/kernel/cpu/sgx/driver/main.c index 87735ce8b5ba..0c831ee5e2de 100644 --- a/arch/x86/kernel/cpu/sgx/driver/main.c +++ b/arch/x86/kernel/cpu/sgx/driver/main.c @@ -68,8 +68,6 @@ static int sgx_mmap(struct file *file, struct vm_area_struct *vma) vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO; vma->vm_private_data = encl; - kref_get(&encl->refcount); - return 0; } diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 6b190eccd02e..9566eb72d417 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -208,7 +208,6 @@ static void sgx_vma_open(struct vm_area_struct *vma) goto error; } - kref_get(&encl->refcount); return; error: @@ -230,8 +229,6 @@ static void sgx_vma_close(struct vm_area_struct *vma) /* Release kref for the VMA. */ kref_put(&encl_mm->refcount, sgx_encl_mm_release); } - - kref_put(&encl->refcount, sgx_encl_release); } static unsigned int sgx_vma_fault(struct vm_fault *vmf)