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Commit 3e1d2eed authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: introduce cgroup_subsys->legacy_name 



This allows cgroup subsystems to use a different name on the unified
hierarchy.  cgroup_subsys->name is used on the unified hierarchy,
->legacy_name elsewhere.  If ->legacy_name is not explicitly set, it's
automatically set to ->name and the userland visible behavior remains
unchanged.

v2: Make parse_cgroupfs_options() only consider ->legacy_name as mount
    options are used only on legacy hierarchies.  Suggested by Li
    Zefan.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: cgroups@vger.kernel.org
parent d98817d4

include/linux/cgroup-defs.h

+3 −0
Original line number Diff line number Diff line
@@ -434,6 +434,9 @@ struct cgroup_subsys { 
	int id;

	const char *name;



	/* optional, initialized automatically during boot if not set */

	const char *legacy_name;



	/* link to parent, protected by cgroup_lock() */

	struct cgroup_root *root;

kernel/cgroup.c

+18 −11
Original line number Diff line number Diff line
@@ -1028,10 +1028,13 @@ static const struct file_operations proc_cgroupstats_operations; 
static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,

			      char *buf)

{

	struct cgroup_subsys *ss = cft->ss;



	if (cft->ss && !(cft->flags & CFTYPE_NO_PREFIX) &&

	    !(cgrp->root->flags & CGRP_ROOT_NOPREFIX))

		snprintf(buf, CGROUP_FILE_NAME_MAX, "%s.%s",

			 cft->ss->name, cft->name);

			 cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,

			 cft->name);

	else

		strncpy(buf, cft->name, CGROUP_FILE_NAME_MAX);

	return buf;
@@ -1336,7 +1339,7 @@ static int cgroup_show_options(struct seq_file *seq, 
	if (root != &cgrp_dfl_root)

		for_each_subsys(ss, ssid)

			if (root->subsys_mask & (1 << ssid))

				seq_printf(seq, ",%s", ss->name);

				seq_printf(seq, ",%s", ss->legacy_name);

	if (root->flags & CGRP_ROOT_NOPREFIX)

		seq_puts(seq, ",noprefix");

	if (root->flags & CGRP_ROOT_XATTR)
@@ -1449,7 +1452,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) 
		}



		for_each_subsys(ss, i) {

			if (strcmp(token, ss->name))

			if (strcmp(token, ss->legacy_name))

				continue;

			if (ss->disabled)

				continue;
@@ -4995,6 +4998,8 @@ int __init cgroup_init_early(void) 


		ss->id = i;

		ss->name = cgroup_subsys_name[i];

		if (!ss->legacy_name)

			ss->legacy_name = cgroup_subsys_name[i];



		if (ss->early_init)

			cgroup_init_subsys(ss, true);
@@ -5142,7 +5147,7 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, 
			for_each_subsys(ss, ssid)

				if (root->subsys_mask & (1 << ssid))

					seq_printf(m, "%s%s", count++ ? "," : "",

						   ss->name);

						   ss->legacy_name);

		if (strlen(root->name))

			seq_printf(m, "%sname=%s", count ? "," : "",

				   root->name);
@@ -5182,7 +5187,7 @@ static int proc_cgroupstats_show(struct seq_file *m, void *v) 


	for_each_subsys(ss, i)

		seq_printf(m, "%s\t%d\t%d\t%d\n",

			   ss->name, ss->root->hierarchy_id,

			   ss->legacy_name, ss->root->hierarchy_id,

			   atomic_read(&ss->root->nr_cgrps), !ss->disabled);



	mutex_unlock(&cgroup_mutex);
@@ -5404,14 +5409,16 @@ static int __init cgroup_disable(char *str) 
			continue;



		for_each_subsys(ss, i) {

			if (!strcmp(token, ss->name)) {

			if (strcmp(token, ss->name) &&

			    strcmp(token, ss->legacy_name))

				continue;



			ss->disabled = 1;

				printk(KERN_INFO "Disabling %s control group"

					" subsystem\n", ss->name);

			printk(KERN_INFO "Disabling %s control group subsystem\n",

			       ss->name);

			break;

		}

	}

	}

	return 1;

}

__setup("cgroup_disable=", cgroup_disable);