cgroup: move v1 mount functions to kernel/cgroup/cgroup-v1.c

Now that the v1 mount code is split into separate functions, move them
to kernel/cgroup/cgroup-v1.c along with the mount option handling
code.  As this puts all v1-only kernfs_syscall_ops in cgroup-v1.c,
move cgroup1_kf_syscall_ops to cgroup-v1.c too.

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

1 files changed, 10 insertions, 400 deletions

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index de6a2ac41d0b..4be306510aff 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -31,7 +31,6 @@
 #include "cgroup-internal.h"
 
 #include <linux/cred.h>
-#include <linux/ctype.h>
 #include <linux/errno.h>
 #include <linux/init_task.h>
 #include <linux/kernel.h>
@@ -49,7 +48,6 @@
 #include <linux/hashtable.h>
 #include <linux/idr.h>
 #include <linux/kthread.h>
-#include <linux/delay.h>
 #include <linux/atomic.h>
 #include <linux/cpuset.h>
 #include <linux/proc_ns.h>
@@ -1078,7 +1076,7 @@ static void cgroup_exit_root_id(struct cgroup_root *root)
 	idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id);
 }
 
-static void cgroup_free_root(struct cgroup_root *root)
+void cgroup_free_root(struct cgroup_root *root)
 {
 	if (root) {
 		idr_destroy(&root->cgroup_idr);
@@ -1232,7 +1230,6 @@ struct cgroup *task_cgroup_from_root(struct task_struct *task,
  * update of a tasks cgroup pointer by cgroup_attach_task()
  */
 
-static struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
 static struct kernfs_syscall_ops cgroup_kf_syscall_ops;
 
 static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,
@@ -1540,8 +1537,8 @@ int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask)
 	return 0;
 }
 
-static int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
-			    struct kernfs_root *kf_root)
+int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
+		     struct kernfs_root *kf_root)
 {
 	int len = 0;
 	char *buf = NULL;
@@ -1567,232 +1564,6 @@ static int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
 	return len;
 }
 
-static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_root)
-{
-	struct cgroup_root *root = cgroup_root_from_kf(kf_root);
-	struct cgroup_subsys *ss;
-	int ssid;
-
-	for_each_subsys(ss, ssid)
-		if (root->subsys_mask & (1 << ssid))
-			seq_show_option(seq, ss->legacy_name, NULL);
-	if (root->flags & CGRP_ROOT_NOPREFIX)
-		seq_puts(seq, ",noprefix");
-	if (root->flags & CGRP_ROOT_XATTR)
-		seq_puts(seq, ",xattr");
-
-	spin_lock(&release_agent_path_lock);
-	if (strlen(root->release_agent_path))
-		seq_show_option(seq, "release_agent",
-				root->release_agent_path);
-	spin_unlock(&release_agent_path_lock);
-
-	if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags))
-		seq_puts(seq, ",clone_children");
-	if (strlen(root->name))
-		seq_show_option(seq, "name", root->name);
-	return 0;
-}
-
-struct cgroup_sb_opts {
-	u16 subsys_mask;
-	unsigned int flags;
-	char *release_agent;
-	bool cpuset_clone_children;
-	char *name;
-	/* User explicitly requested empty subsystem */
-	bool none;
-};
-
-static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
-{
-	char *token, *o = data;
-	bool all_ss = false, one_ss = false;
-	u16 mask = U16_MAX;
-	struct cgroup_subsys *ss;
-	int nr_opts = 0;
-	int i;
-
-#ifdef CONFIG_CPUSETS
-	mask = ~((u16)1 << cpuset_cgrp_id);
-#endif
-
-	memset(opts, 0, sizeof(*opts));
-
-	while ((token = strsep(&o, ",")) != NULL) {
-		nr_opts++;
-
-		if (!*token)
-			return -EINVAL;
-		if (!strcmp(token, "none")) {
-			/* Explicitly have no subsystems */
-			opts->none = true;
-			continue;
-		}
-		if (!strcmp(token, "all")) {
-			/* Mutually exclusive option 'all' + subsystem name */
-			if (one_ss)
-				return -EINVAL;
-			all_ss = true;
-			continue;
-		}
-		if (!strcmp(token, "noprefix")) {
-			opts->flags |= CGRP_ROOT_NOPREFIX;
-			continue;
-		}
-		if (!strcmp(token, "clone_children")) {
-			opts->cpuset_clone_children = true;
-			continue;
-		}
-		if (!strcmp(token, "xattr")) {
-			opts->flags |= CGRP_ROOT_XATTR;
-			continue;
-		}
-		if (!strncmp(token, "release_agent=", 14)) {
-			/* Specifying two release agents is forbidden */
-			if (opts->release_agent)
-				return -EINVAL;
-			opts->release_agent =
-				kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL);
-			if (!opts->release_agent)
-				return -ENOMEM;
-			continue;
-		}
-		if (!strncmp(token, "name=", 5)) {
-			const char *name = token + 5;
-			/* Can't specify an empty name */
-			if (!strlen(name))
-				return -EINVAL;
-			/* Must match [\w.-]+ */
-			for (i = 0; i < strlen(name); i++) {
-				char c = name[i];
-				if (isalnum(c))
-					continue;
-				if ((c == '.') || (c == '-') || (c == '_'))
-					continue;
-				return -EINVAL;
-			}
-			/* Specifying two names is forbidden */
-			if (opts->name)
-				return -EINVAL;
-			opts->name = kstrndup(name,
-					      MAX_CGROUP_ROOT_NAMELEN - 1,
-					      GFP_KERNEL);
-			if (!opts->name)
-				return -ENOMEM;
-
-			continue;
-		}
-
-		for_each_subsys(ss, i) {
-			if (strcmp(token, ss->legacy_name))
-				continue;
-			if (!cgroup_ssid_enabled(i))
-				continue;
-			if (cgroup_ssid_no_v1(i))
-				continue;
-
-			/* Mutually exclusive option 'all' + subsystem name */
-			if (all_ss)
-				return -EINVAL;
-			opts->subsys_mask |= (1 << i);
-			one_ss = true;
-
-			break;
-		}
-		if (i == CGROUP_SUBSYS_COUNT)
-			return -ENOENT;
-	}
-
-	/*
-	 * If the 'all' option was specified select all the subsystems,
-	 * otherwise if 'none', 'name=' and a subsystem name options were
-	 * not specified, let's default to 'all'
-	 */
-	if (all_ss || (!one_ss && !opts->none && !opts->name))
-		for_each_subsys(ss, i)
-			if (cgroup_ssid_enabled(i) && !cgroup_ssid_no_v1(i))
-				opts->subsys_mask |= (1 << i);
-
-	/*
-	 * We either have to specify by name or by subsystems. (So all
-	 * empty hierarchies must have a name).
-	 */
-	if (!opts->subsys_mask && !opts->name)
-		return -EINVAL;
-
-	/*
-	 * Option noprefix was introduced just for backward compatibility
-	 * with the old cpuset, so we allow noprefix only if mounting just
-	 * the cpuset subsystem.
-	 */
-	if ((opts->flags & CGRP_ROOT_NOPREFIX) && (opts->subsys_mask & mask))
-		return -EINVAL;
-
-	/* Can't specify "none" and some subsystems */
-	if (opts->subsys_mask && opts->none)
-		return -EINVAL;
-
-	return 0;
-}
-
-static int cgroup1_remount(struct kernfs_root *kf_root, int *flags, char *data)
-{
-	int ret = 0;
-	struct cgroup_root *root = cgroup_root_from_kf(kf_root);
-	struct cgroup_sb_opts opts;
-	u16 added_mask, removed_mask;
-
-	cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
-
-	/* See what subsystems are wanted */
-	ret = parse_cgroupfs_options(data, &opts);
-	if (ret)
-		goto out_unlock;
-
-	if (opts.subsys_mask != root->subsys_mask || opts.release_agent)
-		pr_warn("option changes via remount are deprecated (pid=%d comm=%s)\n",
-			task_tgid_nr(current), current->comm);
-
-	added_mask = opts.subsys_mask & ~root->subsys_mask;
-	removed_mask = root->subsys_mask & ~opts.subsys_mask;
-
-	/* Don't allow flags or name to change at remount */
-	if ((opts.flags ^ root->flags) ||
-	    (opts.name && strcmp(opts.name, root->name))) {
-		pr_err("option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"\n",
-		       opts.flags, opts.name ?: "", root->flags, root->name);
-		ret = -EINVAL;
-		goto out_unlock;
-	}
-
-	/* remounting is not allowed for populated hierarchies */
-	if (!list_empty(&root->cgrp.self.children)) {
-		ret = -EBUSY;
-		goto out_unlock;
-	}
-
-	ret = rebind_subsystems(root, added_mask);
-	if (ret)
-		goto out_unlock;
-
-	WARN_ON(rebind_subsystems(&cgrp_dfl_root, removed_mask));
-
-	if (opts.release_agent) {
-		spin_lock(&release_agent_path_lock);
-		strcpy(root->release_agent_path, opts.release_agent);
-		spin_unlock(&release_agent_path_lock);
-	}
-
-	trace_cgroup_remount(root);
-
- out_unlock:
-	kfree(opts.release_agent);
-	kfree(opts.name);
-	mutex_unlock(&cgroup_mutex);
-	return ret;
-}
-
 static int cgroup_remount(struct kernfs_root *kf_root, int *flags, char *data)
 {
 	pr_err("remount is not allowed\n");
@@ -1877,8 +1648,7 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp)
 	INIT_WORK(&cgrp->release_agent_work, cgroup_release_agent);
 }
 
-static void init_cgroup_root(struct cgroup_root *root,
-			     struct cgroup_sb_opts *opts)
+void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts)
 {
 	struct cgroup *cgrp = &root->cgrp;
 
@@ -1897,7 +1667,7 @@ static void init_cgroup_root(struct cgroup_root *root,
 		set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags);
 }
 
-static int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
+int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
 {
 	LIST_HEAD(tmp_links);
 	struct cgroup *root_cgrp = &root->cgrp;
@@ -1994,10 +1764,9 @@ out:
 	return ret;
 }
 
-static struct dentry *cgroup_do_mount(struct file_system_type *fs_type,
-				      int flags, struct cgroup_root *root,
-				      unsigned long magic,
-				      struct cgroup_namespace *ns)
+struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
+			       struct cgroup_root *root, unsigned long magic,
+			       struct cgroup_namespace *ns)
 {
 	struct dentry *dentry;
 	bool new_sb;
@@ -2031,155 +1800,6 @@ static struct dentry *cgroup_do_mount(struct file_system_type *fs_type,
 	return dentry;
 }
 
-static struct dentry *cgroup1_mount(struct file_system_type *fs_type,
-				    int flags, void *data,
-				    unsigned long magic,
-				    struct cgroup_namespace *ns)
-{
-	struct super_block *pinned_sb = NULL;
-	struct cgroup_sb_opts opts;
-	struct cgroup_root *root;
-	struct cgroup_subsys *ss;
-	struct dentry *dentry;
-	int i, ret;
-
-	cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
-
-	/* First find the desired set of subsystems */
-	ret = parse_cgroupfs_options(data, &opts);
-	if (ret)
-		goto out_unlock;
-
-	/*
-	 * Destruction of cgroup root is asynchronous, so subsystems may
-	 * still be dying after the previous unmount.  Let's drain the
-	 * dying subsystems.  We just need to ensure that the ones
-	 * unmounted previously finish dying and don't care about new ones
-	 * starting.  Testing ref liveliness is good enough.
-	 */
-	for_each_subsys(ss, i) {
-		if (!(opts.subsys_mask & (1 << i)) ||
-		    ss->root == &cgrp_dfl_root)
-			continue;
-
-		if (!percpu_ref_tryget_live(&ss->root->cgrp.self.refcnt)) {
-			mutex_unlock(&cgroup_mutex);
-			msleep(10);
-			ret = restart_syscall();
-			goto out_free;
-		}
-		cgroup_put(&ss->root->cgrp);
-	}
-
-	for_each_root(root) {
-		bool name_match = false;
-
-		if (root == &cgrp_dfl_root)
-			continue;
-
-		/*
-		 * If we asked for a name then it must match.  Also, if
-		 * name matches but sybsys_mask doesn't, we should fail.
-		 * Remember whether name matched.
-		 */
-		if (opts.name) {
-			if (strcmp(opts.name, root->name))
-				continue;
-			name_match = true;
-		}
-
-		/*
-		 * If we asked for subsystems (or explicitly for no
-		 * subsystems) then they must match.
-		 */
-		if ((opts.subsys_mask || opts.none) &&
-		    (opts.subsys_mask != root->subsys_mask)) {
-			if (!name_match)
-				continue;
-			ret = -EBUSY;
-			goto out_unlock;
-		}
-
-		if (root->flags ^ opts.flags)
-			pr_warn("new mount options do not match the existing superblock, will be ignored\n");
-
-		/*
-		 * We want to reuse @root whose lifetime is governed by its
-		 * ->cgrp.  Let's check whether @root is alive and keep it
-		 * that way.  As cgroup_kill_sb() can happen anytime, we
-		 * want to block it by pinning the sb so that @root doesn't
-		 * get killed before mount is complete.
-		 *
-		 * With the sb pinned, tryget_live can reliably indicate
-		 * whether @root can be reused.  If it's being killed,
-		 * drain it.  We can use wait_queue for the wait but this
-		 * path is super cold.  Let's just sleep a bit and retry.
-		 */
-		pinned_sb = kernfs_pin_sb(root->kf_root, NULL);
-		if (IS_ERR(pinned_sb) ||
-		    !percpu_ref_tryget_live(&root->cgrp.self.refcnt)) {
-			mutex_unlock(&cgroup_mutex);
-			if (!IS_ERR_OR_NULL(pinned_sb))
-				deactivate_super(pinned_sb);
-			msleep(10);
-			ret = restart_syscall();
-			goto out_free;
-		}
-
-		ret = 0;
-		goto out_unlock;
-	}
-
-	/*
-	 * No such thing, create a new one.  name= matching without subsys
-	 * specification is allowed for already existing hierarchies but we
-	 * can't create new one without subsys specification.
-	 */
-	if (!opts.subsys_mask && !opts.none) {
-		ret = -EINVAL;
-		goto out_unlock;
-	}
-
-	/* Hierarchies may only be created in the initial cgroup namespace. */
-	if (ns != &init_cgroup_ns) {
-		ret = -EPERM;
-		goto out_unlock;
-	}
-
-	root = kzalloc(sizeof(*root), GFP_KERNEL);
-	if (!root) {
-		ret = -ENOMEM;
-		goto out_unlock;
-	}
-
-	init_cgroup_root(root, &opts);
-
-	ret = cgroup_setup_root(root, opts.subsys_mask);
-	if (ret)
-		cgroup_free_root(root);
-
-out_unlock:
-	mutex_unlock(&cgroup_mutex);
-out_free:
-	kfree(opts.release_agent);
-	kfree(opts.name);
-
-	if (ret)
-		return ERR_PTR(ret);
-
-	dentry = cgroup_do_mount(&cgroup_fs_type, flags, root,
-				 CGROUP_SUPER_MAGIC, ns);
-
-	/*
-	 * If @pinned_sb, we're reusing an existing root and holding an
-	 * extra ref on its sb.  Mount is complete.  Put the extra ref.
-	 */
-	if (pinned_sb)
-		deactivate_super(pinned_sb);
-
-	return dentry;
-}
-
 static struct dentry *cgroup_mount(struct file_system_type *fs_type,
 			 int flags, const char *unused_dev_name,
 			 void *data)
@@ -4587,8 +4207,7 @@ out_destroy:
 	return ERR_PTR(ret);
 }
 
-static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
-			umode_t mode)
+int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode)
 {
 	struct cgroup *parent, *cgrp;
 	struct kernfs_node *kn;
@@ -4800,7 +4419,7 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
 	return 0;
 };
 
-static int cgroup_rmdir(struct kernfs_node *kn)
+int cgroup_rmdir(struct kernfs_node *kn)
 {
 	struct cgroup *cgrp;
 	int ret = 0;
@@ -4818,15 +4437,6 @@ static int cgroup_rmdir(struct kernfs_node *kn)
 	return ret;
 }
 
-static struct kernfs_syscall_ops cgroup1_kf_syscall_ops = {
-	.remount_fs		= cgroup1_remount,
-	.show_options		= cgroup1_show_options,
-	.rename			= cgroup1_rename,
-	.mkdir			= cgroup_mkdir,
-	.rmdir			= cgroup_rmdir,
-	.show_path		= cgroup_show_path,
-};
-
 static struct kernfs_syscall_ops cgroup_kf_syscall_ops = {
 	.remount_fs		= cgroup_remount,
 	.mkdir			= cgroup_mkdir,