cgroup: replace cgroup_add_cftypes() with cgroup_add_legacy_cftypes()

Currently, cftypes added by cgroup_add_cftypes() are used for both the
unified default hierarchy and legacy ones and subsystems can mark each
file with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE if it has to
appear only on one of them.  This is quite hairy and error-prone.
Also, we may end up exposing interface files to the default hierarchy
without thinking it through.

cgroup_subsys will grow two separate cftype addition functions and
apply each only on the hierarchies of the matching type.  This will
allow organizing cftypes in a lot clearer way and encourage subsystems
to scrutinize the interface which is being exposed in the new default
hierarchy.

In preparation, this patch adds cgroup_add_legacy_cftypes() which
currently is a simple wrapper around cgroup_add_cftypes() and replaces
all cgroup_add_cftypes() usages with it.

While at it, this patch drops a completely spurious return from
__hugetlb_cgroup_file_init().

This patch doesn't introduce any functional differences.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
This commit is contained in:
Tejun Heo 2014-07-15 11:05:09 -04:00
parent 5577964e64
commit 2cf669a58d
6 changed files with 14 additions and 8 deletions

View File

@ -1124,7 +1124,8 @@ int __init blkcg_policy_register(struct blkcg_policy *pol)
/* everything is in place, add intf files for the new policy */
if (pol->cftypes)
WARN_ON(cgroup_add_cftypes(&blkio_cgrp_subsys, pol->cftypes));
WARN_ON(cgroup_add_legacy_cftypes(&blkio_cgrp_subsys,
pol->cftypes));
ret = 0;
out_unlock:
mutex_unlock(&blkcg_pol_mutex);

View File

@ -590,7 +590,7 @@ static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
int cgroup_rm_cftypes(struct cftype *cfts);
bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor);

View File

@ -3170,7 +3170,7 @@ int cgroup_rm_cftypes(struct cftype *cfts)
* function currently returns 0 as long as @cfts registration is successful
* even if some file creation attempts on existing cgroups fail.
*/
int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
static int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
{
int ret;
@ -3195,6 +3195,11 @@ int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
return ret;
}
int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
{
return cgroup_add_cftypes(ss, cfts);
}
/**
* cgroup_task_count - count the number of tasks in a cgroup.
* @cgrp: the cgroup in question

View File

@ -358,9 +358,8 @@ static void __init __hugetlb_cgroup_file_init(int idx)
cft = &h->cgroup_files[4];
memset(cft, 0, sizeof(*cft));
WARN_ON(cgroup_add_cftypes(&hugetlb_cgrp_subsys, h->cgroup_files));
return;
WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys,
h->cgroup_files));
}
void __init hugetlb_cgroup_file_init(void)

View File

@ -7065,7 +7065,8 @@ __setup("swapaccount=", enable_swap_account);
static void __init memsw_file_init(void)
{
WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, memsw_cgroup_files));
WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
memsw_cgroup_files));
}
static void __init enable_swap_cgroup(void)

View File

@ -222,7 +222,7 @@ static struct cftype tcp_files[] = {
static int __init tcp_memcontrol_init(void)
{
WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, tcp_files));
WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, tcp_files));
return 0;
}
__initcall(tcp_memcontrol_init);