According to http://www.drbd.org/download/mainline/, it is recommended to use drbd v8.3.13 with kernel 3.5-3.7.
The following ebuild has been tested with kernel 3.7.1 (however, not in production yet): --- drbd-8.3.12.ebuild 2013-01-10 15:13:24.971967879 +0100 +++ drbd-8.3.13.ebuild 2013-01-10 15:13:01.683617683 +0100 @@ -17,7 +17,6 @@ SLOT="0" src_prepare() { - epatch "${FILESDIR}/drbd-8.3.11-kernel3.patch" # respect LDFLAGS sed -i -e "s/\$(CC) -o/\$(CC) \$(LDFLAGS) -o/" user/Makefile.in || die # respect multilib
*drbd-8.4.2 (17 Jan 2013) *drbd-8.3.15 (17 Jan 2013) 17 Jan 2013; Robin H. Johnson <robbat2@gentoo.org> +drbd-8.3.15.ebuild, +drbd-8.4.2.ebuild, files/drbd-8.0.rc: Bump. Also fix cosmetic bug #219280 that rmmod of a static kernel returns a false error on stop.
Thank you