The patch mapping_nrpages.patch from RT kernel Subject: mm/fs: abstract address_space::nrpages Currently the tree_lock protects mapping->nrpages, this will not be possible much longer. Hence abstract the access to this variable so that it can be easily replaced by an atomic_ulong_t. Signed-off-by: Peter Zijlstra <a.p.zijlstra(a)chello.nl&gt; renames address_space.nrpages to address_space.__nrpages. This patch implements that renaming for crash if address_space.nrpages is invalid. Signed-off-by: Bernhard Walle <bwalle(a)suse.de&gt; --- memory.c | 3 +++ 1 file changed, 3 insertions(+) --- a/memory.c +++ b/memory.c @@ -320,6 +320,9 @@ vm_init(void) MEMBER_OFFSET_INIT(block_device_bd_disk, "block_device", "bd_disk"); MEMBER_OFFSET_INIT(inode_i_mapping, "inode", "i_mapping"); MEMBER_OFFSET_INIT(address_space_nrpages, "address_space", "nrpages"); + if (INVALID_MEMBER(address_space_nrpages)) + MEMBER_OFFSET_INIT(address_space_nrpages, "address_space", "__nrpages"); + MEMBER_OFFSET_INIT(gendisk_major, "gendisk", "major"); MEMBER_OFFSET_INIT(gendisk_fops, "gendisk", "fops"); MEMBER_OFFSET_INIT(gendisk_disk_name, "gendisk", "disk_name"); --