From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Date: Fri, 14 Nov 2008 01:39:21 +0000 Subject: Re: [PATCH] [v2] linux: virtio: Standardize virtio's concept of "page size" Message-Id: <200811141157.22850.rusty@rustcorp.com.au> List-Id: References: <200811130844.57749.rusty@rustcorp.com.au> <1226612913.5339.42.camel@localhost.localdomain> In-Reply-To: <1226612913.5339.42.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Hollis Blanchard Cc: aliguori-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org, markmc-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, xiantao.zhang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kvm-ppc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Friday 14 November 2008 08:18:33 Hollis Blanchard wrote: > On Thu, 2008-11-13 at 08:44 +1030, Rusty Russell wrote: > > Note that I still don't have a balloon patch: want to send me one? > > linux: virtio-balloon: avoid implicit use of Linux page size in balloon > interface Thanks, applied with following diff: Use tabs to indent, and put BUILD_BUG_ON pagesize assumption. Signed-off-by: Rusty Russell diff -r 50e970613233 drivers/virtio/virtio_balloon.c --- a/drivers/virtio/virtio_balloon.c Fri Nov 14 11:40:38 2008 +1030 +++ b/drivers/virtio/virtio_balloon.c Fri Nov 14 11:41:19 2008 +1030 @@ -58,10 +58,11 @@ static u32 page_to_balloon_pfn(struct page *page) { - unsigned long pfn = page_to_pfn(page); + unsigned long pfn = page_to_pfn(page); - /* Convert pfn from Linux page size to balloon page size. */ - return pfn >> (PAGE_SHIFT - VIRTIO_BALLOON_PFN_SHIFT); + BUILD_BUG_ON(PAGE_SHIFT < VIRTIO_BALLOON_PFN_SHIFT); + /* Convert pfn from Linux page size to balloon page size. */ + return pfn >> (PAGE_SHIFT - VIRTIO_BALLOON_PFN_SHIFT); } static void balloon_ack(struct virtqueue *vq)