From patchwork Tue Apr 26 02:14:32 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 8934241 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id CB24B9F372 for ; Tue, 26 Apr 2016 02:15:43 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C93232014A for ; Tue, 26 Apr 2016 02:15:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1EB12015A for ; Tue, 26 Apr 2016 02:15:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751693AbcDZCOj (ORCPT ); Mon, 25 Apr 2016 22:14:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41563 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750817AbcDZCOi (ORCPT ); Mon, 25 Apr 2016 22:14:38 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 569F97F341; Tue, 26 Apr 2016 02:14:37 +0000 (UTC) Received: from hp-dl380pg8-02.lab.eng.pek2.redhat.com (hp-dl380pg8-02.lab.eng.pek2.redhat.com [10.73.8.12]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u3Q2EYN0025842; Mon, 25 Apr 2016 22:14:35 -0400 From: Jason Wang To: mst@redhat.com Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jason Wang Subject: [PATCH 1/2] vhost: simplify work flushing Date: Mon, 25 Apr 2016 22:14:32 -0400 Message-Id: <1461636873-45335-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We used to implement the work flushing through tracking queued seq, done seq, and the number of flushing. This patch simplify this by just implement work flushing through another kind of vhost work with completion. This will be used by lockless enqueuing patch. Signed-off-by: Jason Wang --- drivers/vhost/vhost.c | 53 ++++++++++++++++++++------------------------------- 1 file changed, 21 insertions(+), 32 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 669fef1..73dd16d 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -131,6 +131,19 @@ static void vhost_reset_is_le(struct vhost_virtqueue *vq) vq->is_le = virtio_legacy_is_little_endian(); } +struct vhost_flush_struct { + struct vhost_work work; + struct completion wait_event; +}; + +static void vhost_flush_work(struct vhost_work *work) +{ + struct vhost_flush_struct *s; + + s = container_of(work, struct vhost_flush_struct, work); + complete(&s->wait_event); +} + static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh, poll_table *pt) { @@ -158,8 +171,6 @@ void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn) INIT_LIST_HEAD(&work->node); work->fn = fn; init_waitqueue_head(&work->done); - work->flushing = 0; - work->queue_seq = work->done_seq = 0; } EXPORT_SYMBOL_GPL(vhost_work_init); @@ -211,31 +222,17 @@ void vhost_poll_stop(struct vhost_poll *poll) } EXPORT_SYMBOL_GPL(vhost_poll_stop); -static bool vhost_work_seq_done(struct vhost_dev *dev, struct vhost_work *work, - unsigned seq) -{ - int left; - - spin_lock_irq(&dev->work_lock); - left = seq - work->done_seq; - spin_unlock_irq(&dev->work_lock); - return left <= 0; -} - void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work) { - unsigned seq; - int flushing; + struct vhost_flush_struct flush; + + if (dev->worker) { + init_completion(&flush.wait_event); + vhost_work_init(&flush.work, vhost_flush_work); - spin_lock_irq(&dev->work_lock); - seq = work->queue_seq; - work->flushing++; - spin_unlock_irq(&dev->work_lock); - wait_event(work->done, vhost_work_seq_done(dev, work, seq)); - spin_lock_irq(&dev->work_lock); - flushing = --work->flushing; - spin_unlock_irq(&dev->work_lock); - BUG_ON(flushing < 0); + vhost_work_queue(dev, &flush.work); + wait_for_completion(&flush.wait_event); + } } EXPORT_SYMBOL_GPL(vhost_work_flush); @@ -254,7 +251,6 @@ void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work) spin_lock_irqsave(&dev->work_lock, flags); if (list_empty(&work->node)) { list_add_tail(&work->node, &dev->work_list); - work->queue_seq++; spin_unlock_irqrestore(&dev->work_lock, flags); wake_up_process(dev->worker); } else { @@ -310,7 +306,6 @@ static int vhost_worker(void *data) { struct vhost_dev *dev = data; struct vhost_work *work = NULL; - unsigned uninitialized_var(seq); mm_segment_t oldfs = get_fs(); set_fs(USER_DS); @@ -321,11 +316,6 @@ static int vhost_worker(void *data) set_current_state(TASK_INTERRUPTIBLE); spin_lock_irq(&dev->work_lock); - if (work) { - work->done_seq = seq; - if (work->flushing) - wake_up_all(&work->done); - } if (kthread_should_stop()) { spin_unlock_irq(&dev->work_lock); @@ -336,7 +326,6 @@ static int vhost_worker(void *data) work = list_first_entry(&dev->work_list, struct vhost_work, node); list_del_init(&work->node); - seq = work->queue_seq; } else work = NULL; spin_unlock_irq(&dev->work_lock);