Commit 2cf669a5 authored by Tejun Heo's avatar Tejun Heo
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Acked-by: default avatarLi 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>
parent 5577964e

block/blk-cgroup.c

+2 −1
Original line number Diff line number Diff line
@@ -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);

include/linux/cgroup.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

kernel/cgroup.c

+6 −1
Original line number Diff line number Diff line
@@ -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

mm/hugetlb_cgroup.c

+2 −3
Original line number Diff line number Diff line
@@ -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)

mm/memcontrol.c

+2 −1
Original line number Diff line number Diff line
@@ -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)

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