[Xen-devel] problems of 'blktap'

To:	Xen-devel@xxxxxxxxxxxxxxxxxxx
Subject:	[Xen-devel] problems of 'blktap'
From:	李敏 <fly.limin@xxxxxxxxx>
Date:	Tue, 3 Mar 2009 18:02:47 +0800
Cc:
Delivery-date:	Tue, 03 Mar 2009 02:03:16 -0800
Dkim-signature:	v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:date:message-id:subject :from:to:content-type; bh=zr+Vqh4upiIvChaRL4ozU9GQdsugyEusyWw85qdlfdU=; b=tVILJgQ8RLMCnGkuH4JzQkiZCvQu2Q8WKALqgEa4d09wVo5J5Kihg2xVP8dlSpeLD9 P0wP3brVT6XrJdutKmJr/rlJHwujhhfv6dYtyAX3lk2ke/ubma/t7/lcc4tsGFFreQBt AC0O3TgCg2huy0hdB2uDfvk/zdZe4j6Rmd1sY=
Domainkey-signature:	a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=IopqNQmSO1CTRQROiZnocm/cG4ZrXBMp7wTttICIFgnkRn/WHmWqtbNAx6R92HX1AW FddZ46EW0f68izyzp8zapG7qVhmAyXwoyxHFNEQ8l/OHR/CkZ/EcLOpOGyV7aFiff529 F8T5n+mCF4wiC2J+hIjzefPF2ukqo6l9lvVVw=
Envelope-to:	www-data@xxxxxxxxxxxxxxxxxxx
List-help:	<mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id:	Xen developer discussion <xen-devel.lists.xensource.com>
List-post:	<mailto:xen-devel@lists.xensource.com>
List-subscribe:	<http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe:	<http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender:	xen-devel-bounces@xxxxxxxxxxxxxxxxxxx

when I am studying blktap mechanism , I faced a problem that I can't understand.

In tapdisk.c(xen-3.3.0/tools/blktap/drivers) line 687-689

page = (char *)MMAP_VADDR(info->vstart,
(unsigned long)req->id, i);
page += (req->seg[i].first_sect << SECTOR_SHIFT);

how was the page address caculated? I am not quite understanding.

thanks a lot!
--
Min Li
School of Computer Science and Technology
Cluster and Grid Computing Lab
Services Computing Technology and System Lab
Huazhong University of Science and Technology
Wuhan, 430074, China
Tel: 13986251431 027-65236831
Email: fly.limin@xxxxxxxxx

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

WARNING - OLD ARCHIVES

xen-devel

[Xen-devel] problems of 'blktap'