From 7dbdb199d3bf88f043ea17e97113eb28d5b100bc Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 18 Sep 2015 17:54:23 -0400 Subject: cgroup: replace cftype->mode with CFTYPE_WORLD_WRITABLE cftype->mode allows controllers to give arbitrary permissions to interface knobs. Except for "cgroup.event_control", the existing uses are spurious. * Some explicitly specify S_IRUGO | S_IWUSR even though that's the default. * "cpuset.memory_pressure" specifies S_IRUGO while also setting a write callback which returns -EACCES. All it needs to do is simply not setting a write callback. "cgroup.event_control" uses cftype->mode to make the file world-writable. It's a misdesigned interface and we don't want controllers to be tweaking interface file permissions in general. This patch removes cftype->mode and all its spurious uses and implements CFTYPE_WORLD_WRITABLE for "cgroup.event_control" which is marked as compatibility-only. Signed-off-by: Tejun Heo Cc: Li Zefan Cc: Johannes Weiner --- mm/memcontrol.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'mm/memcontrol.c') diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b35c4cc47a30..e672f2689326 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4060,8 +4060,7 @@ static struct cftype mem_cgroup_legacy_files[] = { { .name = "cgroup.event_control", /* XXX: for compat */ .write = memcg_write_event_control, - .flags = CFTYPE_NO_PREFIX, - .mode = S_IWUGO, + .flags = CFTYPE_NO_PREFIX | CFTYPE_WORLD_WRITABLE, }, { .name = "swappiness", -- cgit v1.2.3-55-g7522