Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753629Ab0BWRBo (ORCPT ); Tue, 23 Feb 2010 12:01:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:1025 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753492Ab0BWRBj (ORCPT ); Tue, 23 Feb 2010 12:01:39 -0500 Date: Tue, 23 Feb 2010 18:57:43 +0200 From: "Michael S. Tsirkin" To: Rusty Russell , kvm@vger.kernel.org, virtualization@lists.osdl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, David Miller , markmc@redhat.com, gleb@redhat.com, herbert.xu@redhat.com, quintela@redhat.com, dlaor@redhat.com, avi@redhat.com Subject: [PATCH 1/3] vhost: logging math fix Message-ID: <51e0f786b06c198ab355abab19f0bd11ac6a167b.1266943453.git.mst@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Mutt-Fcc: =sent User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1434 Lines: 41 vhost was dong some complex math to get offset to log at, and got it wrong by a couple of bytes, while in fact it's simple: get address where we write, subtract start of buffer, add log base. Do it this way. Signed-off-by: Michael S. Tsirkin --- drivers/vhost/vhost.c | 10 ++++++---- 1 files changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 6eb1525..c767279 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1004,10 +1004,12 @@ int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) if (unlikely(vq->log_used)) { /* Make sure data is seen before log. */ smp_wmb(); - log_write(vq->log_base, vq->log_addr + sizeof *vq->used->ring * - (vq->last_used_idx % vq->num), - sizeof *vq->used->ring); - log_write(vq->log_base, vq->log_addr, sizeof *vq->used->ring); + log_write(vq->log_base, + vq->log_addr + ((void *)used - (void *)vq->used), + sizeof *used); + log_write(vq->log_base, + vq->log_addr + offsetof(struct vring_used, idx), + sizeof vq->used->idx); if (vq->log_ctx) eventfd_signal(vq->log_ctx, 1); } -- 1.7.0.18.g0d53a5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/