From patchwork Fri Jan 29 13:19:05 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rusty Russell X-Patchwork-Id: 43911 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 2FE05B7D20 for ; Sat, 30 Jan 2010 00:19:16 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753924Ab0A2NTJ (ORCPT ); Fri, 29 Jan 2010 08:19:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753725Ab0A2NTJ (ORCPT ); Fri, 29 Jan 2010 08:19:09 -0500 Received: from ozlabs.org ([203.10.76.45]:41829 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753412Ab0A2NTI (ORCPT ); Fri, 29 Jan 2010 08:19:08 -0500 Received: from vivaldi.localnet (ppp118-210-11-1.lns20.adl2.internode.on.net [118.210.11.1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPSA id 7B0E9B7D1C; Sat, 30 Jan 2010 00:19:07 +1100 (EST) From: Rusty Russell To: netdev@vger.kernel.org Subject: [PATCH 1/2] virtio: Add ability to detach unused buffers from vrings Date: Fri, 29 Jan 2010 23:49:05 +1030 User-Agent: KMail/1.12.2 (Linux/2.6.31-17-generic; KDE/4.3.2; i686; ; ) Cc: David Miller , virtualization@lists.linux-foundation.org, Shirley Ma , "Michael S. Tsirkin" References: <201001292346.43675.rusty@rustcorp.com.au> In-Reply-To: <201001292346.43675.rusty@rustcorp.com.au> MIME-Version: 1.0 Message-Id: <201001292349.05360.rusty@rustcorp.com.au> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Shirley Ma There's currently no way for a virtio driver to ask for unused buffers, so it has to keep a list itself to reclaim them at shutdown. This is redundant, since virtio_ring stores that information. So add a new hook to do this. Signed-off-by: Shirley Ma Signed-off-by: Amit Shah Signed-off-by: Rusty Russell --- drivers/virtio/virtio_ring.c | 25 +++++++++++++++++++++++++ include/linux/virtio.h | 4 ++++ 2 files changed, 29 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index fbd2ecd..71929ee 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -334,6 +334,30 @@ static bool vring_enable_cb(struct virtqueue *_vq) return true; } +static void *vring_detach_unused_buf(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + unsigned int i; + void *buf; + + START_USE(vq); + + for (i = 0; i < vq->vring.num; i++) { + if (!vq->data[i]) + continue; + /* detach_buf clears data, so grab it now. */ + buf = vq->data[i]; + detach_buf(vq, i); + END_USE(vq); + return buf; + } + /* That should have freed everything. */ + BUG_ON(vq->num_free != vq->vring.num); + + END_USE(vq); + return NULL; +} + irqreturn_t vring_interrupt(int irq, void *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); @@ -360,6 +384,7 @@ static struct virtqueue_ops vring_vq_ops = { .kick = vring_kick, .disable_cb = vring_disable_cb, .enable_cb = vring_enable_cb, + .detach_unused_buf = vring_detach_unused_buf, }; struct virtqueue *vring_new_virtqueue(unsigned int num, diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 057a2e0..f508c65 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -51,6 +51,9 @@ struct virtqueue { * This re-enables callbacks; it returns "false" if there are pending * buffers in the queue, to detect a possible race between the driver * checking for more work, and enabling callbacks. + * @detach_unused_buf: detach first unused buffer + * vq: the struct virtqueue we're talking about. + * Returns NULL or the "data" token handed to add_buf * * Locking rules are straightforward: the driver is responsible for * locking. No two operations may be invoked simultaneously, with the exception @@ -71,6 +74,7 @@ struct virtqueue_ops { void (*disable_cb)(struct virtqueue *vq); bool (*enable_cb)(struct virtqueue *vq); + void *(*detach_unused_buf)(struct virtqueue *vq); }; /**