Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753221Ab1EEIeu (ORCPT ); Thu, 5 May 2011 04:34:50 -0400 Received: from mail-yw0-f46.google.com ([209.85.213.46]:57342 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753107Ab1EEIer convert rfc822-to-8bit (ORCPT ); Thu, 5 May 2011 04:34:47 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=cG7IeQAf8iyK0KeamEhDPK4VVLl4vZRxsxW6emwYpXLwDGYqvxLY0h+dThT4gdVR7x X9PDy2UkcqrrGuEFz3YOwO/JV0r5XQGYMaMMK7WC9b+szVE9wqsaA0o/3bFMXXwk7/50 U2c3t6KwxBITF4pxRbkX6hl3m9U+bbrH6fdkQ= MIME-Version: 1.0 In-Reply-To: References: Date: Thu, 5 May 2011 09:34:46 +0100 Message-ID: Subject: Re: [PATCH 07/18] virtio ring: inline function to check for events From: Stefan Hajnoczi To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, Krishna Kumar , Carsten Otte , lguest@lists.ozlabs.org, Shirley Ma , kvm@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org, habanero@linux.vnet.ibm.com, Heiko Carstens , virtualization@lists.linux-foundation.org, steved@us.ibm.com, Christian Borntraeger , Tom Lendacky , Martin Schwidefsky , linux390@de.ibm.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1503 Lines: 35 On Wed, May 4, 2011 at 9:51 PM, Michael S. Tsirkin wrote: > With the new used_event and avail_event and features, both > host and guest need similar logic to check whether events are > enabled, so it helps to put the common code in the header. > > Note that Xen has similar logic for notification hold-off > in include/xen/interface/io/ring.h with req_event and req_prod > corresponding to event_idx + 1 and new_idx respectively. > +1 comes from the fact that req_event and req_prod in Xen start at 1, > while event index in virtio starts at 0. > > Signed-off-by: Michael S. Tsirkin > --- > ?include/linux/virtio_ring.h | ? 14 ++++++++++++++ > ?1 files changed, 14 insertions(+), 0 deletions(-) > > diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h > index f791772..2a3b0ea 100644 > --- a/include/linux/virtio_ring.h > +++ b/include/linux/virtio_ring.h > @@ -124,6 +124,20 @@ static inline unsigned vring_size(unsigned int num, unsigned long align) > ? ? ? ? ? ? ? ?+ sizeof(__u16) * 3 + sizeof(struct vring_used_elem) * num; > ?} > > +/* The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX */ > +/* Assuming a given event_idx value from the other size, if s/other size/other side/ ? Stefan -- 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/