Merge branch 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup updates from Tejun Heo:

 - cgroup v2 interface is now official.  It's no longer hidden behind a
   devel flag and can be mounted using the new cgroup2 fs type.

   Unfortunately, cpu v2 interface hasn't made it yet due to the
   discussion around in-process hierarchical resource distribution and
   only memory and io controllers can be used on the v2 interface at the
   moment.

 - The existing documentation which has always been a bit of mess is
   relocated under Documentation/cgroup-v1/. Documentation/cgroup-v2.txt
   is added as the authoritative documentation for the v2 interface.

 - Some features are added through for-4.5-ancestor-test branch to
   enable netfilter xt_cgroup match to use cgroup v2 paths.  The actual
   netfilter changes will be merged through the net tree which pulled in
   the said branch.

 - Various cleanups

* 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: rename cgroup documentations
  cgroup: fix a typo.
  cgroup: Remove resource_counter.txt in Documentation/cgroup-legacy/00-INDEX.
  cgroup: demote subsystem init messages to KERN_DEBUG
  cgroup: Fix uninitialized variable warning
  cgroup: put controller Kconfig options in meaningful order
  cgroup: clean up the kernel configuration menu nomenclature
  cgroup_pids: fix a typo.
  Subject: cgroup: Fix incomplete dd command in blkio documentation
  cgroup: kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] and friends
  cpuset: Replace all instances of time_t with time64_t
  cgroup: replace unified-hierarchy.txt with a proper cgroup v2 documentation
  cgroup: rename Documentation/cgroups/ to Documentation/cgroup-legacy/
  cgroup: replace __DEVEL__sane_behavior with cgroup2 fs type

1 files changed, 32 insertions, 49 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index fe95970b1f79..c03a640ef6da 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -211,6 +211,7 @@ static unsigned long have_free_callback __read_mostly;
 /* Ditto for the can_fork callback. */
 static unsigned long have_canfork_callback __read_mostly;
 
+static struct file_system_type cgroup2_fs_type;
 static struct cftype cgroup_dfl_base_files[];
 static struct cftype cgroup_legacy_base_files[];
 
@@ -1623,10 +1624,6 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
 			all_ss = true;
 			continue;
 		}
-		if (!strcmp(token, "__DEVEL__sane_behavior")) {
-			opts->flags |= CGRP_ROOT_SANE_BEHAVIOR;
-			continue;
-		}
 		if (!strcmp(token, "noprefix")) {
 			opts->flags |= CGRP_ROOT_NOPREFIX;
 			continue;
@@ -1693,15 +1690,6 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
 			return -ENOENT;
 	}
 
-	if (opts->flags & CGRP_ROOT_SANE_BEHAVIOR) {
-		pr_warn("sane_behavior: this is still under development and its behaviors will change, proceed at your own risk\n");
-		if (nr_opts != 1) {
-			pr_err("sane_behavior: no other mount options allowed\n");
-			return -EINVAL;
-		}
-		return 0;
-	}
-
 	/*
 	 * If the 'all' option was specified select all the subsystems,
 	 * otherwise if 'none', 'name=' and a subsystem name options were
@@ -1981,6 +1969,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
 			 int flags, const char *unused_dev_name,
 			 void *data)
 {
+	bool is_v2 = fs_type == &cgroup2_fs_type;
 	struct super_block *pinned_sb = NULL;
 	struct cgroup_subsys *ss;
 	struct cgroup_root *root;
@@ -1997,6 +1986,17 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
 	if (!use_task_css_set_links)
 		cgroup_enable_task_cg_lists();
 
+	if (is_v2) {
+		if (data) {
+			pr_err("cgroup2: unknown option \"%s\"\n", (char *)data);
+			return ERR_PTR(-EINVAL);
+		}
+		cgrp_dfl_root_visible = true;
+		root = &cgrp_dfl_root;
+		cgroup_get(&root->cgrp);
+		goto out_mount;
+	}
+
 	mutex_lock(&cgroup_mutex);
 
 	/* First find the desired set of subsystems */
@@ -2004,15 +2004,6 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
 	if (ret)
 		goto out_unlock;
 
-	/* look for a matching existing root */
-	if (opts.flags & CGRP_ROOT_SANE_BEHAVIOR) {
-		cgrp_dfl_root_visible = true;
-		root = &cgrp_dfl_root;
-		cgroup_get(&root->cgrp);
-		ret = 0;
-		goto out_unlock;
-	}
-
 	/*
 	 * Destruction of cgroup root is asynchronous, so subsystems may
 	 * still be dying after the previous unmount.  Let's drain the
@@ -2123,9 +2114,10 @@ out_free:
 
 	if (ret)
 		return ERR_PTR(ret);
-
+out_mount:
 	dentry = kernfs_mount(fs_type, flags, root->kf_root,
-				CGROUP_SUPER_MAGIC, &new_sb);
+			      is_v2 ? CGROUP2_SUPER_MAGIC : CGROUP_SUPER_MAGIC,
+			      &new_sb);
 	if (IS_ERR(dentry) || !new_sb)
 		cgroup_put(&root->cgrp);
 
@@ -2168,6 +2160,12 @@ static struct file_system_type cgroup_fs_type = {
 	.kill_sb = cgroup_kill_sb,
 };
 
+static struct file_system_type cgroup2_fs_type = {
+	.name = "cgroup2",
+	.mount = cgroup_mount,
+	.kill_sb = cgroup_kill_sb,
+};
+
 /**
  * task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
  * @task: target task
@@ -4039,7 +4037,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
 		goto out_err;
 
 	/*
-	 * Migrate tasks one-by-one until @form is empty.  This fails iff
+	 * Migrate tasks one-by-one until @from is empty.  This fails iff
 	 * ->can_attach() fails.
 	 */
 	do {
@@ -5171,7 +5169,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early)
 {
 	struct cgroup_subsys_state *css;
 
-	printk(KERN_INFO "Initializing cgroup subsys %s\n", ss->name);
+	pr_debug("Initializing cgroup subsys %s\n", ss->name);
 
 	mutex_lock(&cgroup_mutex);
 
@@ -5329,6 +5327,7 @@ int __init cgroup_init(void)
 
 	WARN_ON(sysfs_create_mount_point(fs_kobj, "cgroup"));
 	WARN_ON(register_filesystem(&cgroup_fs_type));
+	WARN_ON(register_filesystem(&cgroup2_fs_type));
 	WARN_ON(!proc_create("cgroups", 0, NULL, &proc_cgroupstats_operations));
 
 	return 0;
@@ -5472,19 +5471,6 @@ static const struct file_operations proc_cgroupstats_operations = {
 	.release = single_release,
 };
 
-static void **subsys_canfork_priv_p(void *ss_priv[CGROUP_CANFORK_COUNT], int i)
-{
-	if (CGROUP_CANFORK_START <= i && i < CGROUP_CANFORK_END)
-		return &ss_priv[i - CGROUP_CANFORK_START];
-	return NULL;
-}
-
-static void *subsys_canfork_priv(void *ss_priv[CGROUP_CANFORK_COUNT], int i)
-{
-	void **private = subsys_canfork_priv_p(ss_priv, i);
-	return private ? *private : NULL;
-}
-
 /**
  * cgroup_fork - initialize cgroup related fields during copy_process()
  * @child: pointer to task_struct of forking parent process.
@@ -5507,14 +5493,13 @@ void cgroup_fork(struct task_struct *child)
  * returns an error, the fork aborts with that error code. This allows for
  * a cgroup subsystem to conditionally allow or deny new forks.
  */
-int cgroup_can_fork(struct task_struct *child,
-		    void *ss_priv[CGROUP_CANFORK_COUNT])
+int cgroup_can_fork(struct task_struct *child)
 {
 	struct cgroup_subsys *ss;
 	int i, j, ret;
 
 	for_each_subsys_which(ss, i, &have_canfork_callback) {
-		ret = ss->can_fork(child, subsys_canfork_priv_p(ss_priv, i));
+		ret = ss->can_fork(child);
 		if (ret)
 			goto out_revert;
 	}
@@ -5526,7 +5511,7 @@ out_revert:
 		if (j >= i)
 			break;
 		if (ss->cancel_fork)
-			ss->cancel_fork(child, subsys_canfork_priv(ss_priv, j));
+			ss->cancel_fork(child);
 	}
 
 	return ret;
@@ -5539,15 +5524,14 @@ out_revert:
  * This calls the cancel_fork() callbacks if a fork failed *after*
  * cgroup_can_fork() succeded.
  */
-void cgroup_cancel_fork(struct task_struct *child,
-			void *ss_priv[CGROUP_CANFORK_COUNT])
+void cgroup_cancel_fork(struct task_struct *child)
 {
 	struct cgroup_subsys *ss;
 	int i;
 
 	for_each_subsys(ss, i)
 		if (ss->cancel_fork)
-			ss->cancel_fork(child, subsys_canfork_priv(ss_priv, i));
+			ss->cancel_fork(child);
 }
 
 /**
@@ -5560,8 +5544,7 @@ void cgroup_cancel_fork(struct task_struct *child,
  * cgroup_task_iter_start() - to guarantee that the new task ends up on its
  * list.
  */
-void cgroup_post_fork(struct task_struct *child,
-		      void *old_ss_priv[CGROUP_CANFORK_COUNT])
+void cgroup_post_fork(struct task_struct *child)
 {
 	struct cgroup_subsys *ss;
 	int i;
@@ -5605,7 +5588,7 @@ void cgroup_post_fork(struct task_struct *child,
 	 * and addition to css_set.
 	 */
 	for_each_subsys_which(ss, i, &have_fork_callback)
-		ss->fork(child, subsys_canfork_priv(old_ss_priv, i));
+		ss->fork(child);
 }
 
 /**