4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Arnd Bergmann <[email protected]> commit 358c07fcc3b60ab08d77f1684de8bd81bcf49a1a upstream. A bugfix in v4.8-rc2 introduced a harmless warning when CONFIG_MEMCG_SWAP is disabled but CONFIG_MEMCG is enabled: mm/memcontrol.c:4085:27: error: 'mem_cgroup_id_get_online' defined but not used [-Werror=unused-function] static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) This moves the function inside of the #ifdef block that hides the calling function, to avoid the warning. Fixes: 1f47b61fb407 ("mm: memcontrol: fix swap counter leak on swapout from offline cgroup") Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnd Bergmann <[email protected]> Acked-by: Michal Hocko <[email protected]> Acked-by: Vladimir Davydov <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- mm/memcontrol.c | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-) --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4150,24 +4150,6 @@ static void mem_cgroup_id_get_many(struc atomic_add(n, &memcg->id.ref); } -static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) -{ - while (!atomic_inc_not_zero(&memcg->id.ref)) { - /* - * The root cgroup cannot be destroyed, so it's refcount must - * always be >= 1. - */ - if (WARN_ON_ONCE(memcg == root_mem_cgroup)) { - VM_BUG_ON(1); - break; - } - memcg = parent_mem_cgroup(memcg); - if (!memcg) - memcg = root_mem_cgroup; - } - return memcg; -} - static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n) { if (atomic_sub_and_test(n, &memcg->id.ref)) { @@ -5751,6 +5733,24 @@ static int __init mem_cgroup_init(void) subsys_initcall(mem_cgroup_init); #ifdef CONFIG_MEMCG_SWAP +static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) +{ + while (!atomic_inc_not_zero(&memcg->id.ref)) { + /* + * The root cgroup cannot be destroyed, so it's refcount must + * always be >= 1. + */ + if (WARN_ON_ONCE(memcg == root_mem_cgroup)) { + VM_BUG_ON(1); + break; + } + memcg = parent_mem_cgroup(memcg); + if (!memcg) + memcg = root_mem_cgroup; + } + return memcg; +} + /** * mem_cgroup_swapout - transfer a memsw charge to swap * @page: page whose memsw charge to transfer
