From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta7.messagelabs.com (mail6.bemta7.messagelabs.com [216.82.255.55]) by kanga.kvack.org (Postfix) with ESMTP id 398146B002C for ; Mon, 10 Oct 2011 12:27:34 -0400 (EDT) Subject: Re: [PATCH 1/9] mm: add a "struct subpage" type containing a page, offset and length From: Ian Campbell Date: Mon, 10 Oct 2011 17:27:07 +0100 In-Reply-To: <1318245101-16890-1-git-send-email-ian.campbell@citrix.com> References: <1318245076.21903.408.camel@zakaz.uk.xensource.com> <1318245101-16890-1-git-send-email-ian.campbell@citrix.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Message-ID: <1318264027.21903.470.camel@zakaz.uk.xensource.com> MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: "netdev@vger.kernel.org" Cc: "linux-mm@kvack.org" , linux-kernel , Jens Axboe , Christoph Hellwig (reposting including LKML to catch other potential users) Is this structure of any use to unify other instances of a similar tuple, e.g. biovec, pagefrag etc? Ian. On Mon, 2011-10-10 at 12:11 +0100, Ian Campbell wrote: > A few network drivers currently use skb_frag_struct for this purpose but I have > patches which add additional fields and semantics there which these other uses > do not want. > > A structure for reference sub-page regions seems like a generally useful thing > so do so instead of adding a network subsystem specific structure. > > Signed-off-by: Ian Campbell > Cc: linux-mm@kvack.org > --- > include/linux/mm_types.h | 11 +++++++++++ > 1 files changed, 11 insertions(+), 0 deletions(-) > > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 774b895..dc1d103 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -135,6 +135,17 @@ struct page { > #endif > ; > > +struct subpage { > + struct page *page; > +#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536) > + __u32 page_offset; > + __u32 size; > +#else > + __u16 page_offset; > + __u16 size; > +#endif > +}; > + > typedef unsigned long __nocast vm_flags_t; > > /* -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org