cgroup: move cgroup files under kernel/cgroup/

They're growing to be too many and planned to get split further.  Move
them under their own directory.

 kernel/cgroup.c		-> kernel/cgroup/cgroup.c
 kernel/cgroup_freezer.c	-> kernel/cgroup/freezer.c
 kernel/cgroup_pids.c		-> kernel/cgroup/pids.c
 kernel/cpuset.c		-> kernel/cgroup/cpuset.c

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Acked-by: Zefan Li <lizefan@huawei.com>

1 files changed, 0 insertions, 348 deletions

diff --git a/kernel/cgroup_pids.c b/kernel/cgroup_pids.c
deleted file mode 100644
index 2bd673783f1a..000000000000
--- a/kernel/cgroup_pids.c
+++ /dev/null
@@ -1,348 +0,0 @@
-/*
- * Process number limiting controller for cgroups.
- *
- * Used to allow a cgroup hierarchy to stop any new processes from fork()ing
- * after a certain limit is reached.
- *
- * Since it is trivial to hit the task limit without hitting any kmemcg limits
- * in place, PIDs are a fundamental resource. As such, PID exhaustion must be
- * preventable in the scope of a cgroup hierarchy by allowing resource limiting
- * of the number of tasks in a cgroup.
- *
- * In order to use the `pids` controller, set the maximum number of tasks in
- * pids.max (this is not available in the root cgroup for obvious reasons). The
- * number of processes currently in the cgroup is given by pids.current.
- * Organisational operations are not blocked by cgroup policies, so it is
- * possible to have pids.current > pids.max. However, it is not possible to
- * violate a cgroup policy through fork(). fork() will return -EAGAIN if forking
- * would cause a cgroup policy to be violated.
- *
- * To set a cgroup to have no limit, set pids.max to "max". This is the default
- * for all new cgroups (N.B. that PID limits are hierarchical, so the most
- * stringent limit in the hierarchy is followed).
- *
- * pids.current tracks all child cgroup hierarchies, so parent/pids.current is
- * a superset of parent/child/pids.current.
- *
- * Copyright (C) 2015 Aleksa Sarai <cyphar@cyphar.com>
- *
- * This file is subject to the terms and conditions of version 2 of the GNU
- * General Public License.  See the file COPYING in the main directory of the
- * Linux distribution for more details.
- */
-
-#include <linux/kernel.h>
-#include <linux/threads.h>
-#include <linux/atomic.h>
-#include <linux/cgroup.h>
-#include <linux/slab.h>
-
-#define PIDS_MAX (PID_MAX_LIMIT + 1ULL)
-#define PIDS_MAX_STR "max"
-
-struct pids_cgroup {
-	struct cgroup_subsys_state	css;
-
-	/*
-	 * Use 64-bit types so that we can safely represent "max" as
-	 * %PIDS_MAX = (%PID_MAX_LIMIT + 1).
-	 */
-	atomic64_t			counter;
-	int64_t				limit;
-
-	/* Handle for "pids.events" */
-	struct cgroup_file		events_file;
-
-	/* Number of times fork failed because limit was hit. */
-	atomic64_t			events_limit;
-};
-
-static struct pids_cgroup *css_pids(struct cgroup_subsys_state *css)
-{
-	return container_of(css, struct pids_cgroup, css);
-}
-
-static struct pids_cgroup *parent_pids(struct pids_cgroup *pids)
-{
-	return css_pids(pids->css.parent);
-}
-
-static struct cgroup_subsys_state *
-pids_css_alloc(struct cgroup_subsys_state *parent)
-{
-	struct pids_cgroup *pids;
-
-	pids = kzalloc(sizeof(struct pids_cgroup), GFP_KERNEL);
-	if (!pids)
-		return ERR_PTR(-ENOMEM);
-
-	pids->limit = PIDS_MAX;
-	atomic64_set(&pids->counter, 0);
-	atomic64_set(&pids->events_limit, 0);
-	return &pids->css;
-}
-
-static void pids_css_free(struct cgroup_subsys_state *css)
-{
-	kfree(css_pids(css));
-}
-
-/**
- * pids_cancel - uncharge the local pid count
- * @pids: the pid cgroup state
- * @num: the number of pids to cancel
- *
- * This function will WARN if the pid count goes under 0, because such a case is
- * a bug in the pids controller proper.
- */
-static void pids_cancel(struct pids_cgroup *pids, int num)
-{
-	/*
-	 * A negative count (or overflow for that matter) is invalid,
-	 * and indicates a bug in the `pids` controller proper.
-	 */
-	WARN_ON_ONCE(atomic64_add_negative(-num, &pids->counter));
-}
-
-/**
- * pids_uncharge - hierarchically uncharge the pid count
- * @pids: the pid cgroup state
- * @num: the number of pids to uncharge
- */
-static void pids_uncharge(struct pids_cgroup *pids, int num)
-{
-	struct pids_cgroup *p;
-
-	for (p = pids; parent_pids(p); p = parent_pids(p))
-		pids_cancel(p, num);
-}
-
-/**
- * pids_charge - hierarchically charge the pid count
- * @pids: the pid cgroup state
- * @num: the number of pids to charge
- *
- * This function does *not* follow the pid limit set. It cannot fail and the new
- * pid count may exceed the limit. This is only used for reverting failed
- * attaches, where there is no other way out than violating the limit.
- */
-static void pids_charge(struct pids_cgroup *pids, int num)
-{
-	struct pids_cgroup *p;
-
-	for (p = pids; parent_pids(p); p = parent_pids(p))
-		atomic64_add(num, &p->counter);
-}
-
-/**
- * pids_try_charge - hierarchically try to charge the pid count
- * @pids: the pid cgroup state
- * @num: the number of pids to charge
- *
- * This function follows the set limit. It will fail if the charge would cause
- * the new value to exceed the hierarchical limit. Returns 0 if the charge
- * succeeded, otherwise -EAGAIN.
- */
-static int pids_try_charge(struct pids_cgroup *pids, int num)
-{
-	struct pids_cgroup *p, *q;
-
-	for (p = pids; parent_pids(p); p = parent_pids(p)) {
-		int64_t new = atomic64_add_return(num, &p->counter);
-
-		/*
-		 * Since new is capped to the maximum number of pid_t, if
-		 * p->limit is %PIDS_MAX then we know that this test will never
-		 * fail.
-		 */
-		if (new > p->limit)
-			goto revert;
-	}
-
-	return 0;
-
-revert:
-	for (q = pids; q != p; q = parent_pids(q))
-		pids_cancel(q, num);
-	pids_cancel(p, num);
-
-	return -EAGAIN;
-}
-
-static int pids_can_attach(struct cgroup_taskset *tset)
-{
-	struct task_struct *task;
-	struct cgroup_subsys_state *dst_css;
-
-	cgroup_taskset_for_each(task, dst_css, tset) {
-		struct pids_cgroup *pids = css_pids(dst_css);
-		struct cgroup_subsys_state *old_css;
-		struct pids_cgroup *old_pids;
-
-		/*
-		 * No need to pin @old_css between here and cancel_attach()
-		 * because cgroup core protects it from being freed before
-		 * the migration completes or fails.
-		 */
-		old_css = task_css(task, pids_cgrp_id);
-		old_pids = css_pids(old_css);
-
-		pids_charge(pids, 1);
-		pids_uncharge(old_pids, 1);
-	}
-
-	return 0;
-}
-
-static void pids_cancel_attach(struct cgroup_taskset *tset)
-{
-	struct task_struct *task;
-	struct cgroup_subsys_state *dst_css;
-
-	cgroup_taskset_for_each(task, dst_css, tset) {
-		struct pids_cgroup *pids = css_pids(dst_css);
-		struct cgroup_subsys_state *old_css;
-		struct pids_cgroup *old_pids;
-
-		old_css = task_css(task, pids_cgrp_id);
-		old_pids = css_pids(old_css);
-
-		pids_charge(old_pids, 1);
-		pids_uncharge(pids, 1);
-	}
-}
-
-/*
- * task_css_check(true) in pids_can_fork() and pids_cancel_fork() relies
- * on threadgroup_change_begin() held by the copy_process().
- */
-static int pids_can_fork(struct task_struct *task)
-{
-	struct cgroup_subsys_state *css;
-	struct pids_cgroup *pids;
-	int err;
-
-	css = task_css_check(current, pids_cgrp_id, true);
-	pids = css_pids(css);
-	err = pids_try_charge(pids, 1);
-	if (err) {
-		/* Only log the first time events_limit is incremented. */
-		if (atomic64_inc_return(&pids->events_limit) == 1) {
-			pr_info("cgroup: fork rejected by pids controller in ");
-			pr_cont_cgroup_path(task_cgroup(current, pids_cgrp_id));
-			pr_cont("\n");
-		}
-		cgroup_file_notify(&pids->events_file);
-	}
-	return err;
-}
-
-static void pids_cancel_fork(struct task_struct *task)
-{
-	struct cgroup_subsys_state *css;
-	struct pids_cgroup *pids;
-
-	css = task_css_check(current, pids_cgrp_id, true);
-	pids = css_pids(css);
-	pids_uncharge(pids, 1);
-}
-
-static void pids_free(struct task_struct *task)
-{
-	struct pids_cgroup *pids = css_pids(task_css(task, pids_cgrp_id));
-
-	pids_uncharge(pids, 1);
-}
-
-static ssize_t pids_max_write(struct kernfs_open_file *of, char *buf,
-			      size_t nbytes, loff_t off)
-{
-	struct cgroup_subsys_state *css = of_css(of);
-	struct pids_cgroup *pids = css_pids(css);
-	int64_t limit;
-	int err;
-
-	buf = strstrip(buf);
-	if (!strcmp(buf, PIDS_MAX_STR)) {
-		limit = PIDS_MAX;
-		goto set_limit;
-	}
-
-	err = kstrtoll(buf, 0, &limit);
-	if (err)
-		return err;
-
-	if (limit < 0 || limit >= PIDS_MAX)
-		return -EINVAL;
-
-set_limit:
-	/*
-	 * Limit updates don't need to be mutex'd, since it isn't
-	 * critical that any racing fork()s follow the new limit.
-	 */
-	pids->limit = limit;
-	return nbytes;
-}
-
-static int pids_max_show(struct seq_file *sf, void *v)
-{
-	struct cgroup_subsys_state *css = seq_css(sf);
-	struct pids_cgroup *pids = css_pids(css);
-	int64_t limit = pids->limit;
-
-	if (limit >= PIDS_MAX)
-		seq_printf(sf, "%s\n", PIDS_MAX_STR);
-	else
-		seq_printf(sf, "%lld\n", limit);
-
-	return 0;
-}
-
-static s64 pids_current_read(struct cgroup_subsys_state *css,
-			     struct cftype *cft)
-{
-	struct pids_cgroup *pids = css_pids(css);
-
-	return atomic64_read(&pids->counter);
-}
-
-static int pids_events_show(struct seq_file *sf, void *v)
-{
-	struct pids_cgroup *pids = css_pids(seq_css(sf));
-
-	seq_printf(sf, "max %lld\n", (s64)atomic64_read(&pids->events_limit));
-	return 0;
-}
-
-static struct cftype pids_files[] = {
-	{
-		.name = "max",
-		.write = pids_max_write,
-		.seq_show = pids_max_show,
-		.flags = CFTYPE_NOT_ON_ROOT,
-	},
-	{
-		.name = "current",
-		.read_s64 = pids_current_read,
-		.flags = CFTYPE_NOT_ON_ROOT,
-	},
-	{
-		.name = "events",
-		.seq_show = pids_events_show,
-		.file_offset = offsetof(struct pids_cgroup, events_file),
-		.flags = CFTYPE_NOT_ON_ROOT,
-	},
-	{ }	/* terminate */
-};
-
-struct cgroup_subsys pids_cgrp_subsys = {
-	.css_alloc	= pids_css_alloc,
-	.css_free	= pids_css_free,
-	.can_attach 	= pids_can_attach,
-	.cancel_attach 	= pids_cancel_attach,
-	.can_fork	= pids_can_fork,
-	.cancel_fork	= pids_cancel_fork,
-	.free		= pids_free,
-	.legacy_cftypes	= pids_files,
-	.dfl_cftypes	= pids_files,
-};