From: Rusty Russell Date: Mon, 12 Nov 2007 02:39:18 +0000 (+1100) Subject: virtio: Force use of power-of-two for descriptor ring sizes X-Git-Tag: v2.6.24-rc3~154^2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=42b36cc0ce717deeb10030141a43dede763a3ebe;p=pandora-kernel.git virtio: Force use of power-of-two for descriptor ring sizes The virtio descriptor rings of size N-1 were nicely set up to be aligned to an N-byte boundary. But as Anthony Liguori points out, the free-running indices used by virtio require that the sizes be a power of 2, otherwise we get problems on wrap (demonstrated with lguest). So we replace the clever "2^n-1" scheme with a simple "align to page boundary" scheme: this means that all virtio rings take at least two pages, but it's safer than guessing cache alignment. Signed-off-by: Rusty Russell --- Reading git-diff-tree failed