Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754089AbaKXMD3 (ORCPT ); Mon, 24 Nov 2014 07:03:29 -0500 Received: from mail-la0-f48.google.com ([209.85.215.48]:34446 "EHLO mail-la0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751839AbaKXMDZ (ORCPT ); Mon, 24 Nov 2014 07:03:25 -0500 MIME-Version: 1.0 In-Reply-To: <1416829787-14252-5-git-send-email-mst@redhat.com> References: <1416829787-14252-1-git-send-email-mst@redhat.com> <1416829787-14252-5-git-send-email-mst@redhat.com> Date: Mon, 24 Nov 2014 13:03:24 +0100 X-Google-Sender-Auth: _dSoPuhVqYbwiHy17fXKocV0p20 Message-ID: Subject: Re: [PATCH v3 04/41] virtio: memory access APIs From: Geert Uytterhoeven To: "Michael S. Tsirkin" Cc: "linux-kernel@vger.kernel.org" , David Miller , cornelia.huck@de.ibm.com, rusty@au1.ibm.com, Nicholas Bellinger , Paolo Bonzini , Rusty Russell , Greg Kroah-Hartman , Alexei Starovoitov , Pranavkumar Sawargaonkar , Anup Patel , Sakari Ailus , Bjarke Istrup Pedersen , stephen hemminger , virtualization@lists.linux-foundation.org, linux-api@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 24, 2014 at 12:52 PM, Michael S. Tsirkin wrote: > virtio 1.0 makes all memory structures LE, so > we need APIs to conditionally do a byteswap on BE > architectures. > > To make it easier to check code statically, > add virtio specific types for multi-byte integers > in memory. > > Add low level wrappers that do a byteswap conditionally, these will be > useful e.g. for vhost. Add high level wrappers that > query device endian-ness and act accordingly. > diff --git a/include/linux/virtio_byteorder.h b/include/linux/virtio_byteorder.h > new file mode 100644 > index 0000000..824ed0b > --- /dev/null > +++ b/include/linux/virtio_byteorder.h > +static inline u16 __virtio16_to_cpu(bool little_endian, __virtio16 val) > +{ > + if (little_endian) > + return le16_to_cpu((__force __le16)val); > + else > + return (__force u16)val; > +} What's wrong with just using le16-to_cpu() ... > --- a/include/uapi/linux/virtio_ring.h > +++ b/include/uapi/linux/virtio_ring.h > /* Virtio ring descriptors: 16 bytes. These can chain together via "next". */ > struct vring_desc { > /* Address (guest-physical). */ > - __u64 addr; > + __virtio64 addr; ... and __le64? There's already lots of precedence or this, even in include/uapi/. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- 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/