cgroup: move v1 mount functions to kernel/cgroup/cgroup-v1.c (1592c9b2) · Commits · e / devices / android_kernel_teracube_mt6765

kernel/cgroup/cgroup-internal.h

+25 −3

Original line number	Diff line number	Diff line
		@@ -26,6 +26,16 @@ struct cgrp_cset_link {
		struct list_head cgrp_link;
		};

		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;
		};

		extern struct mutex cgroup_mutex;
		extern spinlock_t css_set_lock;
		extern struct cgroup_subsys *cgroup_subsys[];
		@@ -66,7 +76,13 @@ void cgroup_kn_unlock(struct kernfs_node *kn);
		int cgroup_path_ns_locked(struct cgroup cgrp, char buf, size_t buflen,
		struct cgroup_namespace *ns);

		void cgroup_free_root(struct cgroup_root *root);
		void init_cgroup_root(struct cgroup_root root, struct cgroup_sb_opts opts);
		int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask);
		int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
		struct dentry cgroup_do_mount(struct file_system_type fs_type, int flags,
		struct cgroup_root *root, unsigned long magic,
		struct cgroup_namespace *ns);

		bool cgroup_may_migrate_to(struct cgroup *dst_cgrp);
		void cgroup_migrate_finish(struct list_head *preloaded_csets);
		@@ -86,18 +102,24 @@ ssize_t cgroup_procs_write(struct kernfs_open_file of, char buf, size_t nbytes

		void cgroup_lock_and_drain_offline(struct cgroup *cgrp);

		int cgroup_mkdir(struct kernfs_node parent_kn, const char name, umode_t mode);
		int cgroup_rmdir(struct kernfs_node *kn);
		int cgroup_show_path(struct seq_file sf, struct kernfs_node kf_node,
		struct kernfs_root *kf_root);

		/*
		* cgroup-v1.c
		*/
		extern spinlock_t release_agent_path_lock;
		extern struct cftype cgroup_legacy_base_files[];
		extern const struct file_operations proc_cgroupstats_operations;
		extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;

		bool cgroup_ssid_no_v1(int ssid);
		void cgroup_pidlist_destroy_all(struct cgroup *cgrp);
		int cgroup1_rename(struct kernfs_node kn, struct kernfs_node new_parent,
		const char *new_name_str);
		void cgroup_release_agent(struct work_struct *work);
		void check_for_release(struct cgroup *cgrp);
		struct dentry cgroup1_mount(struct file_system_type fs_type, int flags,
		void *data, unsigned long magic,
		struct cgroup_namespace *ns);

		#endif /* __CGROUP_INTERNAL_H */

kernel/cgroup/cgroup-v1.c

+378 −3

Original line number	Diff line number	Diff line
		#include "cgroup-internal.h"

		#include <linux/ctype.h>
		#include <linux/kmod.h>
		#include <linux/sort.h>
		#include <linux/delay.h>
		#include <linux/mm.h>
		#include <linux/slab.h>
		#include <linux/vmalloc.h>
		@@ -32,7 +34,7 @@ static struct workqueue_struct *cgroup_pidlist_destroy_wq;
		* Protects cgroup_subsys->release_agent_path. Modifying it also requires
		* cgroup_mutex. Reading requires either cgroup_mutex or this spinlock.
		*/
		DEFINE_SPINLOCK(release_agent_path_lock);
		static DEFINE_SPINLOCK(release_agent_path_lock);

		bool cgroup_ssid_no_v1(int ssid)
		{
		@@ -800,7 +802,7 @@ void cgroup_release_agent(struct work_struct *work)
		/*
		* cgroup_rename - Only allow simple rename of directories in place.
		*/
		int cgroup1_rename(struct kernfs_node kn, struct kernfs_node new_parent,
		static int cgroup1_rename(struct kernfs_node kn, struct kernfs_node new_parent,
		const char *new_name_str)
		{
		struct cgroup *cgrp = kn->priv;
		@@ -832,6 +834,379 @@ int cgroup1_rename(struct kernfs_node kn, struct kernfs_node new_parent,
		return ret;
		}

		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;
		}

		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;
		}

		struct kernfs_syscall_ops cgroup1_kf_syscall_ops = {
		.rename = cgroup1_rename,
		.show_options = cgroup1_show_options,
		.remount_fs = cgroup1_remount,
		.mkdir = cgroup_mkdir,
		.rmdir = cgroup_rmdir,
		.show_path = cgroup_show_path,
		};

		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 int __init cgroup1_wq_init(void)
		{
		/*

kernel/cgroup/cgroup.c

+10 −400

File changed.

Preview size limit exceeded, changes collapsed.