From patchwork Mon Dec 10 17:12:29 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vivek Goyal X-Patchwork-Id: 10721997 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 10EB214E2 for ; Mon, 10 Dec 2018 17:21:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DE1182AF9E for ; Mon, 10 Dec 2018 17:21:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D220A2AFD6; Mon, 10 Dec 2018 17:21:29 +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 895C82AF9E for ; Mon, 10 Dec 2018 17:21:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728296AbeLJRNd (ORCPT ); Mon, 10 Dec 2018 12:13:33 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54125 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727356AbeLJRNd (ORCPT ); Mon, 10 Dec 2018 12:13:33 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0A2823154848; Mon, 10 Dec 2018 17:13:33 +0000 (UTC) Received: from horse.redhat.com (unknown [10.18.25.234]) by smtp.corp.redhat.com (Postfix) with ESMTP id 72AC9600D6; Mon, 10 Dec 2018 17:13:30 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id 0F31A223BB9; Mon, 10 Dec 2018 12:13:30 -0500 (EST) From: Vivek Goyal To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: vgoyal@redhat.com, miklos@szeredi.hu, stefanha@redhat.com, dgilbert@redhat.com, sweil@redhat.com, swhiteho@redhat.com Subject: [PATCH 03/52] fuse: rely on mutex_unlock() barrier instead of fput() Date: Mon, 10 Dec 2018 12:12:29 -0500 Message-Id: <20181210171318.16998-4-vgoyal@redhat.com> In-Reply-To: <20181210171318.16998-1-vgoyal@redhat.com> References: <20181210171318.16998-1-vgoyal@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Mon, 10 Dec 2018 17:13:33 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Stefan Hajnoczi fput() will be moved out of this function in a later patch, so we cannot rely on it as the memory barrier for ensuring file->private_data = fud is visible. Luckily there is a mutex_unlock() right before fput() which provides the same effect. Signed-off-by: Stefan Hajnoczi --- fs/fuse/inode.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 0b94b23b02d4..d08cd8bf7705 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1198,12 +1198,11 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) list_add_tail(&fc->entry, &fuse_conn_list); sb->s_root = root_dentry; file->private_data = fud; - mutex_unlock(&fuse_mutex); /* - * atomic_dec_and_test() in fput() provides the necessary - * memory barrier for file->private_data to be visible on all - * CPUs after this + * mutex_unlock() provides the necessary memory barrier for + * file->private_data to be visible on all CPUs after this */ + mutex_unlock(&fuse_mutex); fput(file); fuse_send_init(fc, init_req);