*/
#ifdef CONFIG_PROVE_RCU
DEFINE_MUTEX(cgroup_mutex);
-EXPORT_SYMBOL_GPL(cgroup_mutex); /* only for task_subsys_state_check() */
+EXPORT_SYMBOL_GPL(cgroup_mutex); /* only for lockdep */
#else
static DEFINE_MUTEX(cgroup_mutex);
#endif
*/
static int need_forkexit_callback __read_mostly;
+static struct cftype cgroup_base_files[];
+
static void cgroup_offline_fn(struct work_struct *work);
static int cgroup_destroy_locked(struct cgroup *cgrp);
-static int cgroup_addrm_files(struct cgroup *cgrp, struct cgroup_subsys *subsys,
- struct cftype cfts[], bool is_add);
+static int cgroup_addrm_files(struct cgroup *cgrp, struct cftype cfts[],
+ bool is_add);
/* convenient tests for these bits */
static inline bool cgroup_is_dead(const struct cgroup *cgrp)
* @new_cgrp: cgroup that's being entered by the task
* @template: desired set of css pointers in css_set (pre-calculated)
*
- * Returns true if "cg" matches "old_cg" except for the hierarchy
+ * Returns true if "cset" matches "old_cset" except for the hierarchy
* which "new_cgrp" belongs to, for which it should match "new_cgrp".
*/
static bool compare_css_sets(struct css_set *cset,
static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
static struct dentry *cgroup_lookup(struct inode *, struct dentry *, unsigned int);
static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry);
-static int cgroup_populate_dir(struct cgroup *cgrp, bool base_files,
- unsigned long subsys_mask);
+static int cgroup_populate_dir(struct cgroup *cgrp, unsigned long subsys_mask);
static const struct inode_operations cgroup_dir_inode_operations;
static const struct file_operations proc_cgroupstats_operations;
/*
* Release the subsystem state objects.
*/
- for_each_root_subsys(cgrp->root, ss)
- ss->css_free(cgrp);
+ for_each_root_subsys(cgrp->root, ss) {
+ struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id];
+
+ ss->css_free(css);
+ }
cgrp->root->number_of_cgroups--;
mutex_unlock(&cgroup_mutex);
*/
dput(cgrp->parent->dentry);
- ida_simple_remove(&cgrp->root->cgroup_ida, cgrp->id);
-
/*
* Drop the active superblock reference that we took when we
* created the cgroup. This will free cgrp->root, if we are
}
/**
- * cgroup_clear_directory - selective removal of base and subsystem files
- * @dir: directory containing the files
- * @base_files: true if the base files should be removed
+ * cgroup_clear_dir - remove subsys files in a cgroup directory
+ * @cgrp: target cgroup
* @subsys_mask: mask of the subsystem ids whose files should be removed
*/
-static void cgroup_clear_directory(struct dentry *dir, bool base_files,
- unsigned long subsys_mask)
+static void cgroup_clear_dir(struct cgroup *cgrp, unsigned long subsys_mask)
{
- struct cgroup *cgrp = __d_cgrp(dir);
struct cgroup_subsys *ss;
+ int i;
- for_each_root_subsys(cgrp->root, ss) {
+ for_each_subsys(ss, i) {
struct cftype_set *set;
- if (!test_bit(ss->subsys_id, &subsys_mask))
+
+ if (!test_bit(i, &subsys_mask))
continue;
list_for_each_entry(set, &ss->cftsets, node)
- cgroup_addrm_files(cgrp, NULL, set->cfts, false);
- }
- if (base_files) {
- while (!list_empty(&cgrp->files))
- cgroup_rm_file(cgrp, NULL);
+ cgroup_addrm_files(cgrp, set->cfts, false);
}
}
static void cgroup_d_remove_dir(struct dentry *dentry)
{
struct dentry *parent;
- struct cgroupfs_root *root = dentry->d_sb->s_fs_info;
-
- cgroup_clear_directory(dentry, true, root->subsys_mask);
parent = dentry->d_parent;
spin_lock(&parent->d_lock);
{
struct cgroup *cgrp = &root->top_cgroup;
struct cgroup_subsys *ss;
- int i;
+ unsigned long pinned = 0;
+ int i, ret;
BUG_ON(!mutex_is_locked(&cgroup_mutex));
BUG_ON(!mutex_is_locked(&cgroup_root_mutex));
/* Check that any added subsystems are currently free */
for_each_subsys(ss, i) {
- unsigned long bit = 1UL << i;
-
- if (!(bit & added_mask))
+ if (!(added_mask & (1 << i)))
continue;
+ /* is the subsystem mounted elsewhere? */
if (ss->root != &cgroup_dummy_root) {
- /* Subsystem isn't free */
- return -EBUSY;
+ ret = -EBUSY;
+ goto out_put;
}
+
+ /* pin the module */
+ if (!try_module_get(ss->module)) {
+ ret = -ENOENT;
+ goto out_put;
+ }
+ pinned |= 1 << i;
}
- /* Currently we don't handle adding/removing subsystems when
- * any child cgroups exist. This is theoretically supportable
- * but involves complex error handling, so it's being left until
- * later */
- if (root->number_of_cgroups > 1)
- return -EBUSY;
+ /* subsys could be missing if unloaded between parsing and here */
+ if (added_mask != pinned) {
+ ret = -ENOENT;
+ goto out_put;
+ }
+
+ ret = cgroup_populate_dir(cgrp, added_mask);
+ if (ret)
+ goto out_put;
+
+ /*
+ * Nothing can fail from this point on. Remove files for the
+ * removed subsystems and rebind each subsystem.
+ */
+ cgroup_clear_dir(cgrp, removed_mask);
- /* Process each subsystem */
for_each_subsys(ss, i) {
unsigned long bit = 1UL << i;
list_move(&ss->sibling, &root->subsys_list);
ss->root = root;
if (ss->bind)
- ss->bind(cgrp);
+ ss->bind(cgrp->subsys[i]);
/* refcount was already taken, and we're keeping it */
root->subsys_mask |= bit;
BUG_ON(cgrp->subsys[i]->cgroup != cgrp);
if (ss->bind)
- ss->bind(cgroup_dummy_top);
+ ss->bind(cgroup_dummy_top->subsys[i]);
cgroup_dummy_top->subsys[i]->cgroup = cgroup_dummy_top;
cgrp->subsys[i] = NULL;
cgroup_subsys[i]->root = &cgroup_dummy_root;
/* subsystem is now free - drop reference on module */
module_put(ss->module);
root->subsys_mask &= ~bit;
- } else if (bit & root->subsys_mask) {
- /* Subsystem state should already exist */
- BUG_ON(!cgrp->subsys[i]);
- /*
- * a refcount was taken, but we already had one, so
- * drop the extra reference.
- */
- module_put(ss->module);
-#ifdef CONFIG_MODULE_UNLOAD
- BUG_ON(ss->module && !module_refcount(ss->module));
-#endif
- } else {
- /* Subsystem state shouldn't exist */
- BUG_ON(cgrp->subsys[i]);
}
}
root->flags |= CGRP_ROOT_SUBSYS_BOUND;
return 0;
+
+out_put:
+ for_each_subsys(ss, i)
+ if (pinned & (1 << i))
+ module_put(ss->module);
+ return ret;
}
static int cgroup_show_options(struct seq_file *seq, struct dentry *dentry)
char *token, *o = data;
bool all_ss = false, one_ss = false;
unsigned long mask = (unsigned long)-1;
- bool module_pin_failed = false;
struct cgroup_subsys *ss;
int i;
if (!opts->subsys_mask && !opts->name)
return -EINVAL;
- /*
- * Grab references on all the modules we'll need, so the subsystems
- * don't dance around before rebind_subsystems attaches them. This may
- * take duplicate reference counts on a subsystem that's already used,
- * but rebind_subsystems handles this case.
- */
- for_each_subsys(ss, i) {
- if (!(opts->subsys_mask & (1UL << i)))
- continue;
- if (!try_module_get(cgroup_subsys[i]->module)) {
- module_pin_failed = true;
- break;
- }
- }
- if (module_pin_failed) {
- /*
- * oops, one of the modules was going away. this means that we
- * raced with a module_delete call, and to the user this is
- * essentially a "subsystem doesn't exist" case.
- */
- for (i--; i >= 0; i--) {
- /* drop refcounts only on the ones we took */
- unsigned long bit = 1UL << i;
-
- if (!(bit & opts->subsys_mask))
- continue;
- module_put(cgroup_subsys[i]->module);
- }
- return -ENOENT;
- }
-
return 0;
}
-static void drop_parsed_module_refcounts(unsigned long subsys_mask)
-{
- struct cgroup_subsys *ss;
- int i;
-
- mutex_lock(&cgroup_mutex);
- for_each_subsys(ss, i)
- if (subsys_mask & (1UL << i))
- module_put(cgroup_subsys[i]->module);
- mutex_unlock(&cgroup_mutex);
-}
-
static int cgroup_remount(struct super_block *sb, int *flags, char *data)
{
int ret = 0;
goto out_unlock;
}
- /*
- * Clear out the files of subsystems that should be removed, do
- * this before rebind_subsystems, since rebind_subsystems may
- * change this hierarchy's subsys_list.
- */
- cgroup_clear_directory(cgrp->dentry, false, removed_mask);
-
- ret = rebind_subsystems(root, added_mask, removed_mask);
- if (ret) {
- /* rebind_subsystems failed, re-populate the removed files */
- cgroup_populate_dir(cgrp, false, removed_mask);
+ /* remounting is not allowed for populated hierarchies */
+ if (root->number_of_cgroups > 1) {
+ ret = -EBUSY;
goto out_unlock;
}
- /* re-populate subsystem files */
- cgroup_populate_dir(cgrp, false, added_mask);
+ ret = rebind_subsystems(root, added_mask, removed_mask);
+ if (ret)
+ goto out_unlock;
if (opts.release_agent)
strcpy(root->release_agent_path, opts.release_agent);
mutex_unlock(&cgroup_root_mutex);
mutex_unlock(&cgroup_mutex);
mutex_unlock(&cgrp->dentry->d_inode->i_mutex);
- if (ret)
- drop_parsed_module_refcounts(opts.subsys_mask);
return ret;
}
INIT_LIST_HEAD(&cgrp->release_list);
INIT_LIST_HEAD(&cgrp->pidlists);
mutex_init(&cgrp->pidlist_mutex);
+ cgrp->dummy_css.cgroup = cgrp;
INIT_LIST_HEAD(&cgrp->event_list);
spin_lock_init(&cgrp->event_list_lock);
simple_xattrs_init(&cgrp->xattrs);
cgrp->root = root;
RCU_INIT_POINTER(cgrp->name, &root_cgroup_name);
init_cgroup_housekeeping(cgrp);
+ idr_init(&root->cgroup_idr);
}
static int cgroup_init_root_id(struct cgroupfs_root *root, int start, int end)
*/
root->subsys_mask = opts->subsys_mask;
root->flags = opts->flags;
- ida_init(&root->cgroup_ida);
if (opts->release_agent)
strcpy(root->release_agent_path, opts->release_agent);
if (opts->name)
/* hierarhcy ID shoulid already have been released */
WARN_ON_ONCE(root->hierarchy_id);
- ida_destroy(&root->cgroup_ida);
+ idr_destroy(&root->cgroup_idr);
kfree(root);
}
}
int ret = 0;
struct super_block *sb;
struct cgroupfs_root *new_root;
+ struct list_head tmp_links;
struct inode *inode;
+ const struct cred *cred;
/* First find the desired set of subsystems */
mutex_lock(&cgroup_mutex);
new_root = cgroup_root_from_opts(&opts);
if (IS_ERR(new_root)) {
ret = PTR_ERR(new_root);
- goto drop_modules;
+ goto out_err;
}
opts.new_root = new_root;
if (IS_ERR(sb)) {
ret = PTR_ERR(sb);
cgroup_free_root(opts.new_root);
- goto drop_modules;
+ goto out_err;
}
root = sb->s_fs_info;
BUG_ON(!root);
if (root == opts.new_root) {
/* We used the new root structure, so this is a new hierarchy */
- struct list_head tmp_links;
struct cgroup *root_cgrp = &root->top_cgroup;
struct cgroupfs_root *existing_root;
- const struct cred *cred;
int i;
struct css_set *cset;
mutex_lock(&cgroup_mutex);
mutex_lock(&cgroup_root_mutex);
+ root_cgrp->id = idr_alloc(&root->cgroup_idr, root_cgrp,
+ 0, 1, GFP_KERNEL);
+ if (root_cgrp->id < 0)
+ goto unlock_drop;
+
/* Check for name clashes with existing mounts */
ret = -EBUSY;
if (strlen(root->name))
if (ret)
goto unlock_drop;
+ sb->s_root->d_fsdata = root_cgrp;
+ root_cgrp->dentry = sb->s_root;
+
+ /*
+ * We're inside get_sb() and will call lookup_one_len() to
+ * create the root files, which doesn't work if SELinux is
+ * in use. The following cred dancing somehow works around
+ * it. See 2ce9738ba ("cgroupfs: use init_cred when
+ * populating new cgroupfs mount") for more details.
+ */
+ cred = override_creds(&init_cred);
+
+ ret = cgroup_addrm_files(root_cgrp, cgroup_base_files, true);
+ if (ret)
+ goto rm_base_files;
+
ret = rebind_subsystems(root, root->subsys_mask, 0);
- if (ret == -EBUSY) {
- free_cgrp_cset_links(&tmp_links);
- goto unlock_drop;
- }
+ if (ret)
+ goto rm_base_files;
+
+ revert_creds(cred);
+
/*
* There must be no failure case after here, since rebinding
* takes care of subsystems' refcounts, which are explicitly
* dropped in the failure exit path.
*/
- /* EBUSY should be the only error here */
- BUG_ON(ret);
-
list_add(&root->root_list, &cgroup_roots);
cgroup_root_count++;
- sb->s_root->d_fsdata = root_cgrp;
- root->top_cgroup.dentry = sb->s_root;
-
/* Link the top cgroup in this hierarchy into all
* the css_set objects */
write_lock(&css_set_lock);
BUG_ON(!list_empty(&root_cgrp->children));
BUG_ON(root->number_of_cgroups != 1);
- cred = override_creds(&init_cred);
- cgroup_populate_dir(root_cgrp, true, root->subsys_mask);
- revert_creds(cred);
mutex_unlock(&cgroup_root_mutex);
mutex_unlock(&cgroup_mutex);
mutex_unlock(&inode->i_mutex);
pr_warning("cgroup: new mount options do not match the existing superblock, will be ignored\n");
}
}
-
- /* no subsys rebinding, so refcounts don't change */
- drop_parsed_module_refcounts(opts.subsys_mask);
}
kfree(opts.release_agent);
kfree(opts.name);
return dget(sb->s_root);
+ rm_base_files:
+ free_cgrp_cset_links(&tmp_links);
+ cgroup_addrm_files(&root->top_cgroup, cgroup_base_files, false);
+ revert_creds(cred);
unlock_drop:
cgroup_exit_root_id(root);
mutex_unlock(&cgroup_root_mutex);
mutex_unlock(&inode->i_mutex);
drop_new_super:
deactivate_locked_super(sb);
- drop_modules:
- drop_parsed_module_refcounts(opts.subsys_mask);
out_err:
kfree(opts.release_agent);
kfree(opts.name);
BUG_ON(root->number_of_cgroups != 1);
BUG_ON(!list_empty(&cgrp->children));
+ mutex_lock(&cgrp->dentry->d_inode->i_mutex);
mutex_lock(&cgroup_mutex);
mutex_lock(&cgroup_root_mutex);
mutex_unlock(&cgroup_root_mutex);
mutex_unlock(&cgroup_mutex);
+ mutex_unlock(&cgrp->dentry->d_inode->i_mutex);
simple_xattrs_free(&cgrp->xattrs);
EXPORT_SYMBOL_GPL(cgroup_path);
/**
- * task_cgroup_path_from_hierarchy - cgroup path of a task on a hierarchy
+ * task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
* @task: target task
- * @hierarchy_id: the hierarchy to look up @task's cgroup from
* @buf: the buffer to write the path into
* @buflen: the length of the buffer
*
- * Determine @task's cgroup on the hierarchy specified by @hierarchy_id and
- * copy its path into @buf. This function grabs cgroup_mutex and shouldn't
- * be used inside locks used by cgroup controller callbacks.
+ * Determine @task's cgroup on the first (the one with the lowest non-zero
+ * hierarchy_id) cgroup hierarchy and copy its path into @buf. This
+ * function grabs cgroup_mutex and shouldn't be used inside locks used by
+ * cgroup controller callbacks.
+ *
+ * Returns 0 on success, fails with -%ENAMETOOLONG if @buflen is too short.
*/
-int task_cgroup_path_from_hierarchy(struct task_struct *task, int hierarchy_id,
- char *buf, size_t buflen)
+int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
{
struct cgroupfs_root *root;
- struct cgroup *cgrp = NULL;
- int ret = -ENOENT;
+ struct cgroup *cgrp;
+ int hierarchy_id = 1, ret = 0;
+
+ if (buflen < 2)
+ return -ENAMETOOLONG;
mutex_lock(&cgroup_mutex);
- root = idr_find(&cgroup_hierarchy_idr, hierarchy_id);
+ root = idr_get_next(&cgroup_hierarchy_idr, &hierarchy_id);
+
if (root) {
cgrp = task_cgroup_from_root(task, root);
ret = cgroup_path(cgrp, buf, buflen);
+ } else {
+ /* if no hierarchy exists, everyone is in "/" */
+ memcpy(buf, "/", 2);
}
mutex_unlock(&cgroup_mutex);
-
return ret;
}
-EXPORT_SYMBOL_GPL(task_cgroup_path_from_hierarchy);
+EXPORT_SYMBOL_GPL(task_cgroup_path);
/*
* Control Group taskset
struct task_and_cgroup {
struct task_struct *task;
struct cgroup *cgrp;
- struct css_set *cg;
+ struct css_set *cset;
};
struct cgroup_taskset {
* step 1: check that we can legitimately attach to the cgroup.
*/
for_each_root_subsys(root, ss) {
+ struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id];
+
if (ss->can_attach) {
- retval = ss->can_attach(cgrp, &tset);
+ retval = ss->can_attach(css, &tset);
if (retval) {
failed_ss = ss;
goto out_cancel_attach;
tc = flex_array_get(group, i);
old_cset = task_css_set(tc->task);
- tc->cg = find_css_set(old_cset, cgrp);
- if (!tc->cg) {
+ tc->cset = find_css_set(old_cset, cgrp);
+ if (!tc->cset) {
retval = -ENOMEM;
goto out_put_css_set_refs;
}
*/
for (i = 0; i < group_size; i++) {
tc = flex_array_get(group, i);
- cgroup_task_migrate(tc->cgrp, tc->task, tc->cg);
+ cgroup_task_migrate(tc->cgrp, tc->task, tc->cset);
}
/* nothing is sensitive to fork() after this point. */
* step 4: do subsystem attach callbacks.
*/
for_each_root_subsys(root, ss) {
+ struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id];
+
if (ss->attach)
- ss->attach(cgrp, &tset);
+ ss->attach(css, &tset);
}
/*
if (retval) {
for (i = 0; i < group_size; i++) {
tc = flex_array_get(group, i);
- if (!tc->cg)
+ if (!tc->cset)
break;
- put_css_set(tc->cg);
+ put_css_set(tc->cset);
}
}
out_cancel_attach:
if (retval) {
for_each_root_subsys(root, ss) {
+ struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id];
+
if (ss == failed_ss)
break;
if (ss->cancel_attach)
- ss->cancel_attach(cgrp, &tset);
+ ss->cancel_attach(css, &tset);
}
}
out_free_group_list:
mutex_lock(&cgroup_mutex);
for_each_active_root(root) {
- struct cgroup *from_cg = task_cgroup_from_root(from, root);
+ struct cgroup *from_cgrp = task_cgroup_from_root(from, root);
- retval = cgroup_attach_task(from_cg, tsk, false);
+ retval = cgroup_attach_task(from_cgrp, tsk, false);
if (retval)
break;
}
}
EXPORT_SYMBOL_GPL(cgroup_attach_task_all);
-static int cgroup_tasks_write(struct cgroup *cgrp, struct cftype *cft, u64 pid)
+static int cgroup_tasks_write(struct cgroup_subsys_state *css,
+ struct cftype *cft, u64 pid)
{
- return attach_task_by_pid(cgrp, pid, false);
+ return attach_task_by_pid(css->cgroup, pid, false);
}
-static int cgroup_procs_write(struct cgroup *cgrp, struct cftype *cft, u64 tgid)
+static int cgroup_procs_write(struct cgroup_subsys_state *css,
+ struct cftype *cft, u64 tgid)
{
- return attach_task_by_pid(cgrp, tgid, true);
+ return attach_task_by_pid(css->cgroup, tgid, true);
}
-static int cgroup_release_agent_write(struct cgroup *cgrp, struct cftype *cft,
- const char *buffer)
+static int cgroup_release_agent_write(struct cgroup_subsys_state *css,
+ struct cftype *cft, const char *buffer)
{
- BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
+ BUILD_BUG_ON(sizeof(css->cgroup->root->release_agent_path) < PATH_MAX);
if (strlen(buffer) >= PATH_MAX)
return -EINVAL;
- if (!cgroup_lock_live_group(cgrp))
+ if (!cgroup_lock_live_group(css->cgroup))
return -ENODEV;
mutex_lock(&cgroup_root_mutex);
- strcpy(cgrp->root->release_agent_path, buffer);
+ strcpy(css->cgroup->root->release_agent_path, buffer);
mutex_unlock(&cgroup_root_mutex);
mutex_unlock(&cgroup_mutex);
return 0;
}
-static int cgroup_release_agent_show(struct cgroup *cgrp, struct cftype *cft,
- struct seq_file *seq)
+static int cgroup_release_agent_show(struct cgroup_subsys_state *css,
+ struct cftype *cft, struct seq_file *seq)
{
+ struct cgroup *cgrp = css->cgroup;
+
if (!cgroup_lock_live_group(cgrp))
return -ENODEV;
seq_puts(seq, cgrp->root->release_agent_path);
return 0;
}
-static int cgroup_sane_behavior_show(struct cgroup *cgrp, struct cftype *cft,
- struct seq_file *seq)
+static int cgroup_sane_behavior_show(struct cgroup_subsys_state *css,
+ struct cftype *cft, struct seq_file *seq)
{
- seq_printf(seq, "%d\n", cgroup_sane_behavior(cgrp));
+ seq_printf(seq, "%d\n", cgroup_sane_behavior(css->cgroup));
return 0;
}
+/* return the css for the given cgroup file */
+static struct cgroup_subsys_state *cgroup_file_css(struct cfent *cfe)
+{
+ struct cftype *cft = cfe->type;
+ struct cgroup *cgrp = __d_cgrp(cfe->dentry->d_parent);
+
+ if (cft->ss)
+ return cgrp->subsys[cft->ss->subsys_id];
+ return &cgrp->dummy_css;
+}
+
/* A buffer size big enough for numbers or short strings */
#define CGROUP_LOCAL_BUFFER_SIZE 64
-static ssize_t cgroup_write_X64(struct cgroup *cgrp, struct cftype *cft,
- struct file *file,
- const char __user *userbuf,
- size_t nbytes, loff_t *unused_ppos)
+static ssize_t cgroup_write_X64(struct cgroup_subsys_state *css,
+ struct cftype *cft, struct file *file,
+ const char __user *userbuf, size_t nbytes,
+ loff_t *unused_ppos)
{
char buffer[CGROUP_LOCAL_BUFFER_SIZE];
int retval = 0;
u64 val = simple_strtoull(strstrip(buffer), &end, 0);
if (*end)
return -EINVAL;
- retval = cft->write_u64(cgrp, cft, val);
+ retval = cft->write_u64(css, cft, val);
} else {
s64 val = simple_strtoll(strstrip(buffer), &end, 0);
if (*end)
return -EINVAL;
- retval = cft->write_s64(cgrp, cft, val);
+ retval = cft->write_s64(css, cft, val);
}
if (!retval)
retval = nbytes;
return retval;
}
-static ssize_t cgroup_write_string(struct cgroup *cgrp, struct cftype *cft,
- struct file *file,
- const char __user *userbuf,
- size_t nbytes, loff_t *unused_ppos)
+static ssize_t cgroup_write_string(struct cgroup_subsys_state *css,
+ struct cftype *cft, struct file *file,
+ const char __user *userbuf, size_t nbytes,
+ loff_t *unused_ppos)
{
char local_buffer[CGROUP_LOCAL_BUFFER_SIZE];
int retval = 0;
}
buffer[nbytes] = 0; /* nul-terminate */
- retval = cft->write_string(cgrp, cft, strstrip(buffer));
+ retval = cft->write_string(css, cft, strstrip(buffer));
if (!retval)
retval = nbytes;
out:
}
static ssize_t cgroup_file_write(struct file *file, const char __user *buf,
- size_t nbytes, loff_t *ppos)
+ size_t nbytes, loff_t *ppos)
{
+ struct cfent *cfe = __d_cfe(file->f_dentry);
struct cftype *cft = __d_cft(file->f_dentry);
- struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
+ struct cgroup_subsys_state *css = cgroup_file_css(cfe);
- if (cgroup_is_dead(cgrp))
- return -ENODEV;
if (cft->write)
- return cft->write(cgrp, cft, file, buf, nbytes, ppos);
+ return cft->write(css, cft, file, buf, nbytes, ppos);
if (cft->write_u64 || cft->write_s64)
- return cgroup_write_X64(cgrp, cft, file, buf, nbytes, ppos);
+ return cgroup_write_X64(css, cft, file, buf, nbytes, ppos);
if (cft->write_string)
- return cgroup_write_string(cgrp, cft, file, buf, nbytes, ppos);
+ return cgroup_write_string(css, cft, file, buf, nbytes, ppos);
if (cft->trigger) {
- int ret = cft->trigger(cgrp, (unsigned int)cft->private);
+ int ret = cft->trigger(css, (unsigned int)cft->private);
return ret ? ret : nbytes;
}
return -EINVAL;
}
-static ssize_t cgroup_read_u64(struct cgroup *cgrp, struct cftype *cft,
- struct file *file,
- char __user *buf, size_t nbytes,
- loff_t *ppos)
+static ssize_t cgroup_read_u64(struct cgroup_subsys_state *css,
+ struct cftype *cft, struct file *file,
+ char __user *buf, size_t nbytes, loff_t *ppos)
{
char tmp[CGROUP_LOCAL_BUFFER_SIZE];
- u64 val = cft->read_u64(cgrp, cft);
+ u64 val = cft->read_u64(css, cft);
int len = sprintf(tmp, "%llu\n", (unsigned long long) val);
return simple_read_from_buffer(buf, nbytes, ppos, tmp, len);
}
-static ssize_t cgroup_read_s64(struct cgroup *cgrp, struct cftype *cft,
- struct file *file,
- char __user *buf, size_t nbytes,
- loff_t *ppos)
+static ssize_t cgroup_read_s64(struct cgroup_subsys_state *css,
+ struct cftype *cft, struct file *file,
+ char __user *buf, size_t nbytes, loff_t *ppos)
{
char tmp[CGROUP_LOCAL_BUFFER_SIZE];
- s64 val = cft->read_s64(cgrp, cft);
+ s64 val = cft->read_s64(css, cft);
int len = sprintf(tmp, "%lld\n", (long long) val);
return simple_read_from_buffer(buf, nbytes, ppos, tmp, len);
}
static ssize_t cgroup_file_read(struct file *file, char __user *buf,
- size_t nbytes, loff_t *ppos)
+ size_t nbytes, loff_t *ppos)
{
+ struct cfent *cfe = __d_cfe(file->f_dentry);
struct cftype *cft = __d_cft(file->f_dentry);
- struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
-
- if (cgroup_is_dead(cgrp))
- return -ENODEV;
+ struct cgroup_subsys_state *css = cgroup_file_css(cfe);
if (cft->read)
- return cft->read(cgrp, cft, file, buf, nbytes, ppos);
+ return cft->read(css, cft, file, buf, nbytes, ppos);
if (cft->read_u64)
- return cgroup_read_u64(cgrp, cft, file, buf, nbytes, ppos);
+ return cgroup_read_u64(css, cft, file, buf, nbytes, ppos);
if (cft->read_s64)
- return cgroup_read_s64(cgrp, cft, file, buf, nbytes, ppos);
+ return cgroup_read_s64(css, cft, file, buf, nbytes, ppos);
return -EINVAL;
}
* supports string->u64 maps, but can be extended in future.
*/
-struct cgroup_seqfile_state {
- struct cftype *cft;
- struct cgroup *cgroup;
-};
-
static int cgroup_map_add(struct cgroup_map_cb *cb, const char *key, u64 value)
{
struct seq_file *sf = cb->state;
static int cgroup_seqfile_show(struct seq_file *m, void *arg)
{
- struct cgroup_seqfile_state *state = m->private;
- struct cftype *cft = state->cft;
+ struct cfent *cfe = m->private;
+ struct cftype *cft = cfe->type;
+ struct cgroup_subsys_state *css = cgroup_file_css(cfe);
+
if (cft->read_map) {
struct cgroup_map_cb cb = {
.fill = cgroup_map_add,
.state = m,
};
- return cft->read_map(state->cgroup, cft, &cb);
+ return cft->read_map(css, cft, &cb);
}
- return cft->read_seq_string(state->cgroup, cft, m);
-}
-
-static int cgroup_seqfile_release(struct inode *inode, struct file *file)
-{
- struct seq_file *seq = file->private_data;
- kfree(seq->private);
- return single_release(inode, file);
+ return cft->read_seq_string(css, cft, m);
}
static const struct file_operations cgroup_seqfile_operations = {
.read = seq_read,
.write = cgroup_file_write,
.llseek = seq_lseek,
- .release = cgroup_seqfile_release,
+ .release = single_release,
};
static int cgroup_file_open(struct inode *inode, struct file *file)
{
+ struct cfent *cfe = __d_cfe(file->f_dentry);
+ struct cftype *cft = __d_cft(file->f_dentry);
+ struct cgroup_subsys_state *css = cgroup_file_css(cfe);
int err;
- struct cftype *cft;
err = generic_file_open(inode, file);
if (err)
return err;
- cft = __d_cft(file->f_dentry);
- if (cft->read_map || cft->read_seq_string) {
- struct cgroup_seqfile_state *state;
-
- state = kzalloc(sizeof(*state), GFP_USER);
- if (!state)
- return -ENOMEM;
+ /*
+ * If the file belongs to a subsystem, pin the css. Will be
+ * unpinned either on open failure or release. This ensures that
+ * @css stays alive for all file operations.
+ */
+ if (css->ss && !css_tryget(css))
+ return -ENODEV;
- state->cft = cft;
- state->cgroup = __d_cgrp(file->f_dentry->d_parent);
+ if (cft->read_map || cft->read_seq_string) {
file->f_op = &cgroup_seqfile_operations;
- err = single_open(file, cgroup_seqfile_show, state);
- if (err < 0)
- kfree(state);
- } else if (cft->open)
+ err = single_open(file, cgroup_seqfile_show, cfe);
+ } else if (cft->open) {
err = cft->open(inode, file);
- else
- err = 0;
+ }
+ if (css->ss && err)
+ css_put(css);
return err;
}
static int cgroup_file_release(struct inode *inode, struct file *file)
{
+ struct cfent *cfe = __d_cfe(file->f_dentry);
struct cftype *cft = __d_cft(file->f_dentry);
+ struct cgroup_subsys_state *css = cgroup_file_css(cfe);
+ int ret = 0;
+
if (cft->release)
- return cft->release(inode, file);
- return 0;
+ ret = cft->release(inode, file);
+ if (css->ss)
+ css_put(css);
+ return ret;
}
/*
return mode;
}
-static int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys,
- struct cftype *cft)
+static int cgroup_add_file(struct cgroup *cgrp, struct cftype *cft)
{
struct dentry *dir = cgrp->dentry;
struct cgroup *parent = __d_cgrp(dir);
umode_t mode;
char name[MAX_CGROUP_TYPE_NAMELEN + MAX_CFTYPE_NAME + 2] = { 0 };
- if (subsys && !(cgrp->root->flags & CGRP_ROOT_NOPREFIX)) {
- strcpy(name, subsys->name);
+ if (cft->ss && !(cgrp->root->flags & CGRP_ROOT_NOPREFIX)) {
+ strcpy(name, cft->ss->name);
strcat(name, ".");
}
strcat(name, cft->name);
return error;
}
-static int cgroup_addrm_files(struct cgroup *cgrp, struct cgroup_subsys *subsys,
- struct cftype cfts[], bool is_add)
+/**
+ * cgroup_addrm_files - add or remove files to a cgroup directory
+ * @cgrp: the target cgroup
+ * @cfts: array of cftypes to be added
+ * @is_add: whether to add or remove
+ *
+ * Depending on @is_add, add or remove files defined by @cfts on @cgrp.
+ * For removals, this function never fails. If addition fails, this
+ * function doesn't remove files already added. The caller is responsible
+ * for cleaning up.
+ */
+static int cgroup_addrm_files(struct cgroup *cgrp, struct cftype cfts[],
+ bool is_add)
{
struct cftype *cft;
- int err, ret = 0;
+ int ret;
+
+ lockdep_assert_held(&cgrp->dentry->d_inode->i_mutex);
+ lockdep_assert_held(&cgroup_mutex);
for (cft = cfts; cft->name[0] != '\0'; cft++) {
/* does cft->flags tell us to skip this file on @cgrp? */
continue;
if (is_add) {
- err = cgroup_add_file(cgrp, subsys, cft);
- if (err)
+ ret = cgroup_add_file(cgrp, cft);
+ if (ret) {
pr_warn("cgroup_addrm_files: failed to add %s, err=%d\n",
- cft->name, err);
- ret = err;
+ cft->name, ret);
+ return ret;
+ }
} else {
cgroup_rm_file(cgrp, cft);
}
}
- return ret;
+ return 0;
}
static void cgroup_cfts_prepare(void)
/*
* Thanks to the entanglement with vfs inode locking, we can't walk
* the existing cgroups under cgroup_mutex and create files.
- * Instead, we use cgroup_for_each_descendant_pre() and drop RCU
- * read lock before calling cgroup_addrm_files().
+ * Instead, we use css_for_each_descendant_pre() and drop RCU read
+ * lock before calling cgroup_addrm_files().
*/
mutex_lock(&cgroup_mutex);
}
-static void cgroup_cfts_commit(struct cgroup_subsys *ss,
- struct cftype *cfts, bool is_add)
+static int cgroup_cfts_commit(struct cftype *cfts, bool is_add)
__releases(&cgroup_mutex)
{
LIST_HEAD(pending);
- struct cgroup *cgrp, *root = &ss->root->top_cgroup;
+ struct cgroup_subsys *ss = cfts[0].ss;
+ struct cgroup *root = &ss->root->top_cgroup;
struct super_block *sb = ss->root->sb;
struct dentry *prev = NULL;
struct inode *inode;
+ struct cgroup_subsys_state *css;
u64 update_before;
+ int ret = 0;
/* %NULL @cfts indicates abort and don't bother if @ss isn't attached */
if (!cfts || ss->root == &cgroup_dummy_root ||
!atomic_inc_not_zero(&sb->s_active)) {
mutex_unlock(&cgroup_mutex);
- return;
+ return 0;
}
/*
inode = root->dentry->d_inode;
mutex_lock(&inode->i_mutex);
mutex_lock(&cgroup_mutex);
- cgroup_addrm_files(root, ss, cfts, is_add);
+ ret = cgroup_addrm_files(root, cfts, is_add);
mutex_unlock(&cgroup_mutex);
mutex_unlock(&inode->i_mutex);
+ if (ret)
+ goto out_deact;
+
/* add/rm files for all cgroups created before */
rcu_read_lock();
- cgroup_for_each_descendant_pre(cgrp, root) {
+ css_for_each_descendant_pre(css, cgroup_css(root, ss->subsys_id)) {
+ struct cgroup *cgrp = css->cgroup;
+
if (cgroup_is_dead(cgrp))
continue;
mutex_lock(&inode->i_mutex);
mutex_lock(&cgroup_mutex);
if (cgrp->serial_nr < update_before && !cgroup_is_dead(cgrp))
- cgroup_addrm_files(cgrp, ss, cfts, is_add);
+ ret = cgroup_addrm_files(cgrp, cfts, is_add);
mutex_unlock(&cgroup_mutex);
mutex_unlock(&inode->i_mutex);
rcu_read_lock();
+ if (ret)
+ break;
}
rcu_read_unlock();
dput(prev);
+out_deact:
deactivate_super(sb);
+ return ret;
}
/**
int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
{
struct cftype_set *set;
+ struct cftype *cft;
+ int ret;
set = kzalloc(sizeof(*set), GFP_KERNEL);
if (!set)
return -ENOMEM;
+ for (cft = cfts; cft->name[0] != '\0'; cft++)
+ cft->ss = ss;
+
cgroup_cfts_prepare();
set->cfts = cfts;
list_add_tail(&set->node, &ss->cftsets);
- cgroup_cfts_commit(ss, cfts, true);
-
- return 0;
+ ret = cgroup_cfts_commit(cfts, true);
+ if (ret)
+ cgroup_rm_cftypes(cfts);
+ return ret;
}
EXPORT_SYMBOL_GPL(cgroup_add_cftypes);
/**
* cgroup_rm_cftypes - remove an array of cftypes from a subsystem
- * @ss: target cgroup subsystem
* @cfts: zero-length name terminated array of cftypes
*
- * Unregister @cfts from @ss. Files described by @cfts are removed from
- * all existing cgroups to which @ss is attached and all future cgroups
- * won't have them either. This function can be called anytime whether @ss
- * is attached or not.
+ * Unregister @cfts. Files described by @cfts are removed from all
+ * existing cgroups and all future cgroups won't have them either. This
+ * function can be called anytime whether @cfts' subsys is attached or not.
*
* Returns 0 on successful unregistration, -ENOENT if @cfts is not
- * registered with @ss.
+ * registered.
*/
-int cgroup_rm_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
+int cgroup_rm_cftypes(struct cftype *cfts)
{
struct cftype_set *set;
+ if (!cfts || !cfts[0].ss)
+ return -ENOENT;
+
cgroup_cfts_prepare();
- list_for_each_entry(set, &ss->cftsets, node) {
+ list_for_each_entry(set, &cfts[0].ss->cftsets, node) {
if (set->cfts == cfts) {
list_del(&set->node);
kfree(set);
- cgroup_cfts_commit(ss, cfts, false);
+ cgroup_cfts_commit(cfts, false);
return 0;
}
}
- cgroup_cfts_commit(ss, NULL, false);
+ cgroup_cfts_commit(NULL, false);
return -ENOENT;
}
}
/**
- * cgroup_next_sibling - find the next sibling of a given cgroup
- * @pos: the current cgroup
+ * css_next_child - find the next child of a given css
+ * @pos_css: the current position (%NULL to initiate traversal)
+ * @parent_css: css whose children to walk
*
- * This function returns the next sibling of @pos and should be called
- * under RCU read lock. The only requirement is that @pos is accessible.
- * The next sibling is guaranteed to be returned regardless of @pos's
- * state.
+ * This function returns the next child of @parent_css and should be called
+ * under RCU read lock. The only requirement is that @parent_css and
+ * @pos_css are accessible. The next sibling is guaranteed to be returned
+ * regardless of their states.
*/
-struct cgroup *cgroup_next_sibling(struct cgroup *pos)
+struct cgroup_subsys_state *
+css_next_child(struct cgroup_subsys_state *pos_css,
+ struct cgroup_subsys_state *parent_css)
{
+ struct cgroup *pos = pos_css ? pos_css->cgroup : NULL;
+ struct cgroup *cgrp = parent_css->cgroup;
struct cgroup *next;
WARN_ON_ONCE(!rcu_read_lock_held());
* safe to dereference from this RCU critical section. If
* ->sibling.next is inaccessible, cgroup_is_dead() is guaranteed
* to be visible as %true here.
+ *
+ * If @pos is dead, its next pointer can't be dereferenced;
+ * however, as each cgroup is given a monotonically increasing
+ * unique serial number and always appended to the sibling list,
+ * the next one can be found by walking the parent's children until
+ * we see a cgroup with higher serial number than @pos's. While
+ * this path can be slower, it's taken only when either the current
+ * cgroup is removed or iteration and removal race.
*/
- if (likely(!cgroup_is_dead(pos))) {
+ if (!pos) {
+ next = list_entry_rcu(cgrp->children.next, struct cgroup, sibling);
+ } else if (likely(!cgroup_is_dead(pos))) {
next = list_entry_rcu(pos->sibling.next, struct cgroup, sibling);
- if (&next->sibling != &pos->parent->children)
- return next;
- return NULL;
+ } else {
+ list_for_each_entry_rcu(next, &cgrp->children, sibling)
+ if (next->serial_nr > pos->serial_nr)
+ break;
}
- /*
- * Can't dereference the next pointer. Each cgroup is given a
- * monotonically increasing unique serial number and always
- * appended to the sibling list, so the next one can be found by
- * walking the parent's children until we see a cgroup with higher
- * serial number than @pos's.
- *
- * While this path can be slow, it's taken only when either the
- * current cgroup is removed or iteration and removal race.
- */
- list_for_each_entry_rcu(next, &pos->parent->children, sibling)
- if (next->serial_nr > pos->serial_nr)
- return next;
- return NULL;
+ if (&next->sibling == &cgrp->children)
+ return NULL;
+
+ if (parent_css->ss)
+ return cgroup_css(next, parent_css->ss->subsys_id);
+ else
+ return &next->dummy_css;
}
-EXPORT_SYMBOL_GPL(cgroup_next_sibling);
+EXPORT_SYMBOL_GPL(css_next_child);
/**
- * cgroup_next_descendant_pre - find the next descendant for pre-order walk
+ * css_next_descendant_pre - find the next descendant for pre-order walk
* @pos: the current position (%NULL to initiate traversal)
- * @cgroup: cgroup whose descendants to walk
+ * @root: css whose descendants to walk
*
- * To be used by cgroup_for_each_descendant_pre(). Find the next
- * descendant to visit for pre-order traversal of @cgroup's descendants.
+ * To be used by css_for_each_descendant_pre(). Find the next descendant
+ * to visit for pre-order traversal of @root's descendants.
*
* While this function requires RCU read locking, it doesn't require the
* whole traversal to be contained in a single RCU critical section. This
* function will return the correct next descendant as long as both @pos
- * and @cgroup are accessible and @pos is a descendant of @cgroup.
+ * and @root are accessible and @pos is a descendant of @root.
*/
-struct cgroup *cgroup_next_descendant_pre(struct cgroup *pos,
- struct cgroup *cgroup)
+struct cgroup_subsys_state *
+css_next_descendant_pre(struct cgroup_subsys_state *pos,
+ struct cgroup_subsys_state *root)
{
- struct cgroup *next;
+ struct cgroup_subsys_state *next;
WARN_ON_ONCE(!rcu_read_lock_held());
- /* if first iteration, pretend we just visited @cgroup */
+ /* if first iteration, pretend we just visited @root */
if (!pos)
- pos = cgroup;
+ pos = root;
/* visit the first child if exists */
- next = list_first_or_null_rcu(&pos->children, struct cgroup, sibling);
+ next = css_next_child(NULL, pos);
if (next)
return next;
/* no child, visit my or the closest ancestor's next sibling */
- while (pos != cgroup) {
- next = cgroup_next_sibling(pos);
+ while (pos != root) {
+ next = css_next_child(pos, css_parent(pos));
if (next)
return next;
- pos = pos->parent;
+ pos = css_parent(pos);
}
return NULL;
}
-EXPORT_SYMBOL_GPL(cgroup_next_descendant_pre);
+EXPORT_SYMBOL_GPL(css_next_descendant_pre);
/**
- * cgroup_rightmost_descendant - return the rightmost descendant of a cgroup
- * @pos: cgroup of interest
+ * css_rightmost_descendant - return the rightmost descendant of a css
+ * @pos: css of interest
*
- * Return the rightmost descendant of @pos. If there's no descendant,
- * @pos is returned. This can be used during pre-order traversal to skip
+ * Return the rightmost descendant of @pos. If there's no descendant, @pos
+ * is returned. This can be used during pre-order traversal to skip
* subtree of @pos.
*
* While this function requires RCU read locking, it doesn't require the
* function will return the correct rightmost descendant as long as @pos is
* accessible.
*/
-struct cgroup *cgroup_rightmost_descendant(struct cgroup *pos)
+struct cgroup_subsys_state *
+css_rightmost_descendant(struct cgroup_subsys_state *pos)
{
- struct cgroup *last, *tmp;
+ struct cgroup_subsys_state *last, *tmp;
WARN_ON_ONCE(!rcu_read_lock_held());
last = pos;
/* ->prev isn't RCU safe, walk ->next till the end */
pos = NULL;
- list_for_each_entry_rcu(tmp, &last->children, sibling)
+ css_for_each_child(tmp, last)
pos = tmp;
} while (pos);
return last;
}
-EXPORT_SYMBOL_GPL(cgroup_rightmost_descendant);
+EXPORT_SYMBOL_GPL(css_rightmost_descendant);
-static struct cgroup *cgroup_leftmost_descendant(struct cgroup *pos)
+static struct cgroup_subsys_state *
+css_leftmost_descendant(struct cgroup_subsys_state *pos)
{
- struct cgroup *last;
+ struct cgroup_subsys_state *last;
do {
last = pos;
- pos = list_first_or_null_rcu(&pos->children, struct cgroup,
- sibling);
+ pos = css_next_child(NULL, pos);
} while (pos);
return last;
}
/**
- * cgroup_next_descendant_post - find the next descendant for post-order walk
+ * css_next_descendant_post - find the next descendant for post-order walk
* @pos: the current position (%NULL to initiate traversal)
- * @cgroup: cgroup whose descendants to walk
+ * @root: css whose descendants to walk
*
- * To be used by cgroup_for_each_descendant_post(). Find the next
- * descendant to visit for post-order traversal of @cgroup's descendants.
+ * To be used by css_for_each_descendant_post(). Find the next descendant
+ * to visit for post-order traversal of @root's descendants.
*
* While this function requires RCU read locking, it doesn't require the
* whole traversal to be contained in a single RCU critical section. This
* function will return the correct next descendant as long as both @pos
* and @cgroup are accessible and @pos is a descendant of @cgroup.
*/
-struct cgroup *cgroup_next_descendant_post(struct cgroup *pos,
- struct cgroup *cgroup)
+struct cgroup_subsys_state *
+css_next_descendant_post(struct cgroup_subsys_state *pos,
+ struct cgroup_subsys_state *root)
{
- struct cgroup *next;
+ struct cgroup_subsys_state *next;
WARN_ON_ONCE(!rcu_read_lock_held());
/* if first iteration, visit the leftmost descendant */
if (!pos) {
- next = cgroup_leftmost_descendant(cgroup);
- return next != cgroup ? next : NULL;
+ next = css_leftmost_descendant(root);
+ return next != root ? next : NULL;
}
/* if there's an unvisited sibling, visit its leftmost descendant */
- next = cgroup_next_sibling(pos);
+ next = css_next_child(pos, css_parent(pos));
if (next)
- return cgroup_leftmost_descendant(next);
+ return css_leftmost_descendant(next);
/* no sibling left, visit parent */
- next = pos->parent;
- return next != cgroup ? next : NULL;
+ next = css_parent(pos);
+ return next != root ? next : NULL;
}
-EXPORT_SYMBOL_GPL(cgroup_next_descendant_post);
+EXPORT_SYMBOL_GPL(css_next_descendant_post);
void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it)
__acquires(css_set_lock)
* guarantees forward progress and that we don't miss any tasks.
*/
heap->size = 0;
- cgroup_iter_start(scan->cg, &it);
- while ((p = cgroup_iter_next(scan->cg, &it))) {
+ cgroup_iter_start(scan->cgrp, &it);
+ while ((p = cgroup_iter_next(scan->cgrp, &it))) {
/*
* Only affect tasks that qualify per the caller's callback,
* if he provided one
* the heap and wasn't inserted
*/
}
- cgroup_iter_end(scan->cg, &it);
+ cgroup_iter_end(scan->cgrp, &it);
if (heap->size) {
for (i = 0; i < heap->size; i++) {
{
struct cgroup_scanner scan;
- scan.cg = from;
+ scan.cgrp = from;
scan.test_task = NULL; /* select all tasks in cgroup */
scan.process_task = cgroup_transfer_one_task;
scan.heap = NULL;
/* pointer to the cgroup we belong to, for list removal purposes */
struct cgroup *owner;
/* protects the other fields */
- struct rw_semaphore mutex;
+ struct rw_semaphore rwsem;
};
/*
struct pid_namespace *ns = task_active_pid_ns(current);
/*
- * We can't drop the pidlist_mutex before taking the l->mutex in case
+ * We can't drop the pidlist_mutex before taking the l->rwsem in case
* the last ref-holder is trying to remove l from the list at the same
* time. Holding the pidlist_mutex precludes somebody taking whichever
* list we find out from under us - compare release_pid_array().
list_for_each_entry(l, &cgrp->pidlists, links) {
if (l->key.type == type && l->key.ns == ns) {
/* make sure l doesn't vanish out from under us */
- down_write(&l->mutex);
+ down_write(&l->rwsem);
mutex_unlock(&cgrp->pidlist_mutex);
return l;
}
mutex_unlock(&cgrp->pidlist_mutex);
return l;
}
- init_rwsem(&l->mutex);
- down_write(&l->mutex);
+ init_rwsem(&l->rwsem);
+ down_write(&l->rwsem);
l->key.type = type;
l->key.ns = get_pid_ns(ns);
l->owner = cgrp;
l->list = array;
l->length = length;
l->use_count++;
- up_write(&l->mutex);
+ up_write(&l->rwsem);
*lp = l;
return 0;
}
int index = 0, pid = *pos;
int *iter;
- down_read(&l->mutex);
+ down_read(&l->rwsem);
if (pid) {
int end = l->length;
static void cgroup_pidlist_stop(struct seq_file *s, void *v)
{
struct cgroup_pidlist *l = s->private;
- up_read(&l->mutex);
+ up_read(&l->rwsem);
}
static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos)
* pidlist_mutex, we have to take pidlist_mutex first.
*/
mutex_lock(&l->owner->pidlist_mutex);
- down_write(&l->mutex);
+ down_write(&l->rwsem);
BUG_ON(!l->use_count);
if (!--l->use_count) {
/* we're the last user if refcount is 0; remove and free */
mutex_unlock(&l->owner->pidlist_mutex);
pidlist_free(l->list);
put_pid_ns(l->key.ns);
- up_write(&l->mutex);
+ up_write(&l->rwsem);
kfree(l);
return;
}
mutex_unlock(&l->owner->pidlist_mutex);
- up_write(&l->mutex);
+ up_write(&l->rwsem);
}
static int cgroup_pidlist_release(struct inode *inode, struct file *file)
return cgroup_pidlist_open(file, CGROUP_FILE_PROCS);
}
-static u64 cgroup_read_notify_on_release(struct cgroup *cgrp,
- struct cftype *cft)
+static u64 cgroup_read_notify_on_release(struct cgroup_subsys_state *css,
+ struct cftype *cft)
{
- return notify_on_release(cgrp);
+ return notify_on_release(css->cgroup);
}
-static int cgroup_write_notify_on_release(struct cgroup *cgrp,
- struct cftype *cft,
- u64 val)
+static int cgroup_write_notify_on_release(struct cgroup_subsys_state *css,
+ struct cftype *cft, u64 val)
{
- clear_bit(CGRP_RELEASABLE, &cgrp->flags);
+ clear_bit(CGRP_RELEASABLE, &css->cgroup->flags);
if (val)
- set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
+ set_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
else
- clear_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
+ clear_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
return 0;
}
* Input must be in format '<event_fd> <control_fd> <args>'.
* Interpretation of args is defined by control file implementation.
*/
-static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
- const char *buffer)
+static int cgroup_write_event_control(struct cgroup_subsys_state *css,
+ struct cftype *cft, const char *buffer)
{
- struct cgroup_event *event = NULL;
+ struct cgroup *cgrp = css->cgroup;
+ struct cgroup_event *event;
struct cgroup *cgrp_cfile;
unsigned int efd, cfd;
- struct file *efile = NULL;
- struct file *cfile = NULL;
+ struct file *efile;
+ struct file *cfile;
char *endp;
int ret;
efile = eventfd_fget(efd);
if (IS_ERR(efile)) {
ret = PTR_ERR(efile);
- goto fail;
+ goto out_kfree;
}
event->eventfd = eventfd_ctx_fileget(efile);
if (IS_ERR(event->eventfd)) {
ret = PTR_ERR(event->eventfd);
- goto fail;
+ goto out_put_efile;
}
cfile = fget(cfd);
if (!cfile) {
ret = -EBADF;
- goto fail;
+ goto out_put_eventfd;
}
/* the process need read permission on control file */
/* AV: shouldn't we check that it's been opened for read instead? */
ret = inode_permission(file_inode(cfile), MAY_READ);
if (ret < 0)
- goto fail;
+ goto out_put_cfile;
event->cft = __file_cft(cfile);
if (IS_ERR(event->cft)) {
ret = PTR_ERR(event->cft);
- goto fail;
+ goto out_put_cfile;
}
/*
cgrp_cfile = __d_cgrp(cfile->f_dentry->d_parent);
if (cgrp_cfile != cgrp) {
ret = -EINVAL;
- goto fail;
+ goto out_put_cfile;
}
if (!event->cft->register_event || !event->cft->unregister_event) {
ret = -EINVAL;
- goto fail;
+ goto out_put_cfile;
}
ret = event->cft->register_event(cgrp, event->cft,
event->eventfd, buffer);
if (ret)
- goto fail;
+ goto out_put_cfile;
efile->f_op->poll(efile, &event->pt);
return 0;
-fail:
- if (cfile)
- fput(cfile);
-
- if (event && event->eventfd && !IS_ERR(event->eventfd))
- eventfd_ctx_put(event->eventfd);
-
- if (!IS_ERR_OR_NULL(efile))
- fput(efile);
-
+out_put_cfile:
+ fput(cfile);
+out_put_eventfd:
+ eventfd_ctx_put(event->eventfd);
+out_put_efile:
+ fput(efile);
+out_kfree:
kfree(event);
return ret;
}
-static u64 cgroup_clone_children_read(struct cgroup *cgrp,
- struct cftype *cft)
+static u64 cgroup_clone_children_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
{
- return test_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
+ return test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
}
-static int cgroup_clone_children_write(struct cgroup *cgrp,
- struct cftype *cft,
- u64 val)
+static int cgroup_clone_children_write(struct cgroup_subsys_state *css,
+ struct cftype *cft, u64 val)
{
if (val)
- set_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
+ set_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
else
- clear_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
+ clear_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
return 0;
}
};
/**
- * cgroup_populate_dir - selectively creation of files in a directory
+ * cgroup_populate_dir - create subsys files in a cgroup directory
* @cgrp: target cgroup
- * @base_files: true if the base files should be added
* @subsys_mask: mask of the subsystem ids whose files should be added
+ *
+ * On failure, no file is added.
*/
-static int cgroup_populate_dir(struct cgroup *cgrp, bool base_files,
- unsigned long subsys_mask)
+static int cgroup_populate_dir(struct cgroup *cgrp, unsigned long subsys_mask)
{
- int err;
struct cgroup_subsys *ss;
-
- if (base_files) {
- err = cgroup_addrm_files(cgrp, NULL, cgroup_base_files, true);
- if (err < 0)
- return err;
- }
+ int i, ret = 0;
/* process cftsets of each subsystem */
- for_each_root_subsys(cgrp->root, ss) {
+ for_each_subsys(ss, i) {
struct cftype_set *set;
- if (!test_bit(ss->subsys_id, &subsys_mask))
+
+ if (!test_bit(i, &subsys_mask))
continue;
- list_for_each_entry(set, &ss->cftsets, node)
- cgroup_addrm_files(cgrp, ss, set->cfts, true);
+ list_for_each_entry(set, &ss->cftsets, node) {
+ ret = cgroup_addrm_files(cgrp, set->cfts, true);
+ if (ret < 0)
+ goto err;
+ }
}
/* This cgroup is ready now */
}
return 0;
+err:
+ cgroup_clear_dir(cgrp, subsys_mask);
+ return ret;
}
static void css_dput_fn(struct work_struct *work)
struct cgroup *cgrp)
{
css->cgroup = cgrp;
+ css->ss = ss;
css->flags = 0;
css->id = NULL;
if (cgrp == cgroup_dummy_top)
INIT_WORK(&css->dput_work, css_dput_fn);
}
-/* invoke ->post_create() on a new CSS and mark it online if successful */
+/* invoke ->css_online() on a new CSS and mark it online if successful */
static int online_css(struct cgroup_subsys *ss, struct cgroup *cgrp)
{
+ struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id];
int ret = 0;
lockdep_assert_held(&cgroup_mutex);
if (ss->css_online)
- ret = ss->css_online(cgrp);
+ ret = ss->css_online(css);
if (!ret)
- cgrp->subsys[ss->subsys_id]->flags |= CSS_ONLINE;
+ css->flags |= CSS_ONLINE;
return ret;
}
-/* if the CSS is online, invoke ->pre_destory() on it and mark it offline */
+/* if the CSS is online, invoke ->css_offline() on it and mark it offline */
static void offline_css(struct cgroup_subsys *ss, struct cgroup *cgrp)
- __releases(&cgroup_mutex) __acquires(&cgroup_mutex)
{
struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id];
return;
if (ss->css_offline)
- ss->css_offline(cgrp);
+ ss->css_offline(css);
- cgrp->subsys[ss->subsys_id]->flags &= ~CSS_ONLINE;
+ css->flags &= ~CSS_ONLINE;
}
/*
goto err_free_cgrp;
rcu_assign_pointer(cgrp->name, name);
- cgrp->id = ida_simple_get(&root->cgroup_ida, 1, 0, GFP_KERNEL);
+ /*
+ * Temporarily set the pointer to NULL, so idr_find() won't return
+ * a half-baked cgroup.
+ */
+ cgrp->id = idr_alloc(&root->cgroup_idr, NULL, 1, 0, GFP_KERNEL);
if (cgrp->id < 0)
goto err_free_name;
for_each_root_subsys(root, ss) {
struct cgroup_subsys_state *css;
- css = ss->css_alloc(cgrp);
+ css = ss->css_alloc(parent->subsys[ss->subsys_id]);
if (IS_ERR(css)) {
err = PTR_ERR(css);
goto err_free_all;
}
err = percpu_ref_init(&css->refcnt, css_release);
- if (err)
+ if (err) {
+ ss->css_free(css);
goto err_free_all;
+ }
init_cgroup_css(css, ss, cgrp);
}
}
- err = cgroup_populate_dir(cgrp, true, root->subsys_mask);
+ idr_replace(&root->cgroup_idr, cgrp, cgrp->id);
+
+ err = cgroup_addrm_files(cgrp, cgroup_base_files, true);
+ if (err)
+ goto err_destroy;
+
+ err = cgroup_populate_dir(cgrp, root->subsys_mask);
if (err)
goto err_destroy;
if (css) {
percpu_ref_cancel_init(&css->refcnt);
- ss->css_free(cgrp);
+ ss->css_free(css);
}
}
mutex_unlock(&cgroup_mutex);
/* Release the reference count that we took on the superblock */
deactivate_super(sb);
err_free_id:
- ida_simple_remove(&root->cgroup_ida, cgrp->id);
+ idr_remove(&root->cgroup_idr, cgrp->id);
err_free_name:
kfree(rcu_dereference_raw(cgrp->name));
err_free_cgrp:
/*
* Mark @cgrp dead. This prevents further task migration and child
* creation by disabling cgroup_lock_live_group(). Note that
- * CGRP_DEAD assertion is depended upon by cgroup_next_sibling() to
+ * CGRP_DEAD assertion is depended upon by css_next_child() to
* resume iteration after dropping RCU read lock. See
- * cgroup_next_sibling() for details.
+ * css_next_child() for details.
*/
set_bit(CGRP_DEAD, &cgrp->flags);
raw_spin_unlock(&release_list_lock);
/*
- * Remove @cgrp directory. The removal puts the base ref but we
- * aren't quite done with @cgrp yet, so hold onto it.
+ * Clear and remove @cgrp directory. The removal puts the base ref
+ * but we aren't quite done with @cgrp yet, so hold onto it.
*/
+ cgroup_clear_dir(cgrp, cgrp->root->subsys_mask);
+ cgroup_addrm_files(cgrp, cgroup_base_files, false);
dget(d);
cgroup_d_remove_dir(d);
/* delete this cgroup from parent->children */
list_del_rcu(&cgrp->sibling);
+ /*
+ * We should remove the cgroup object from idr before its grace
+ * period starts, so we won't be looking up a cgroup while the
+ * cgroup is being freed.
+ */
+ idr_remove(&cgrp->root->cgroup_idr, cgrp->id);
+ cgrp->id = -1;
+
dput(d);
set_bit(CGRP_RELEASABLE, &parent->flags);
* deregistration.
*/
if (ss->base_cftypes) {
+ struct cftype *cft;
+
+ for (cft = ss->base_cftypes; cft->name[0] != '\0'; cft++)
+ cft->ss = ss;
+
ss->base_cftset.cfts = ss->base_cftypes;
list_add_tail(&ss->base_cftset.node, &ss->cftsets);
}
/* Create the top cgroup state for this subsystem */
list_add(&ss->sibling, &cgroup_dummy_root.subsys_list);
ss->root = &cgroup_dummy_root;
- css = ss->css_alloc(cgroup_dummy_top);
+ css = ss->css_alloc(cgroup_dummy_top->subsys[ss->subsys_id]);
/* We don't handle early failures gracefully */
BUG_ON(IS_ERR(css));
init_cgroup_css(css, ss, cgroup_dummy_top);
* struct, so this can happen first (i.e. before the dummy root
* attachment).
*/
- css = ss->css_alloc(cgroup_dummy_top);
+ css = ss->css_alloc(cgroup_dummy_top->subsys[ss->subsys_id]);
if (IS_ERR(css)) {
/* failure case - need to deassign the cgroup_subsys[] slot. */
cgroup_subsys[ss->subsys_id] = NULL;
/*
* we shouldn't be called if the subsystem is in use, and the use of
- * try_module_get in parse_cgroupfs_options should ensure that it
+ * try_module_get() in rebind_subsystems() should ensure that it
* doesn't start being used while we're killing it off.
*/
BUG_ON(ss->root != &cgroup_dummy_root);
* the cgrp->subsys pointer to find their state. note that this
* also takes care of freeing the css_id.
*/
- ss->css_free(cgroup_dummy_top);
+ ss->css_free(cgroup_dummy_top->subsys[ss->subsys_id]);
cgroup_dummy_top->subsys[ss->subsys_id] = NULL;
mutex_unlock(&cgroup_mutex);
BUG_ON(cgroup_init_root_id(&cgroup_dummy_root, 0, 1));
+ err = idr_alloc(&cgroup_dummy_root.cgroup_idr, cgroup_dummy_top,
+ 0, 1, GFP_KERNEL);
+ BUG_ON(err < 0);
+
mutex_unlock(&cgroup_root_mutex);
mutex_unlock(&cgroup_mutex);
*/
for_each_builtin_subsys(ss, i) {
if (ss->exit) {
- struct cgroup *old_cgrp = cset->subsys[i]->cgroup;
- struct cgroup *cgrp = task_cgroup(tsk, i);
+ struct cgroup_subsys_state *old_css = cset->subsys[i];
+ struct cgroup_subsys_state *css = task_css(tsk, i);
- ss->exit(cgrp, old_cgrp, tsk);
+ ss->exit(css, old_css, tsk);
}
}
}
}
#ifdef CONFIG_CGROUP_DEBUG
-static struct cgroup_subsys_state *debug_css_alloc(struct cgroup *cgrp)
+static struct cgroup_subsys_state *
+debug_css_alloc(struct cgroup_subsys_state *parent_css)
{
struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL);
return css;
}
-static void debug_css_free(struct cgroup *cgrp)
+static void debug_css_free(struct cgroup_subsys_state *css)
{
- kfree(cgrp->subsys[debug_subsys_id]);
+ kfree(css);
}
-static u64 debug_taskcount_read(struct cgroup *cgrp, struct cftype *cft)
+static u64 debug_taskcount_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
{
- return cgroup_task_count(cgrp);
+ return cgroup_task_count(css->cgroup);
}
-static u64 current_css_set_read(struct cgroup *cgrp, struct cftype *cft)
+static u64 current_css_set_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
{
return (u64)(unsigned long)current->cgroups;
}
-static u64 current_css_set_refcount_read(struct cgroup *cgrp,
+static u64 current_css_set_refcount_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
u64 count;
return count;
}
-static int current_css_set_cg_links_read(struct cgroup *cgrp,
+static int current_css_set_cg_links_read(struct cgroup_subsys_state *css,
struct cftype *cft,
struct seq_file *seq)
{
}
#define MAX_TASKS_SHOWN_PER_CSS 25
-static int cgroup_css_links_read(struct cgroup *cgrp,
- struct cftype *cft,
- struct seq_file *seq)
+static int cgroup_css_links_read(struct cgroup_subsys_state *css,
+ struct cftype *cft, struct seq_file *seq)
{
struct cgrp_cset_link *link;
read_lock(&css_set_lock);
- list_for_each_entry(link, &cgrp->cset_links, cset_link) {
+ list_for_each_entry(link, &css->cgroup->cset_links, cset_link) {
struct css_set *cset = link->cset;
struct task_struct *task;
int count = 0;
return 0;
}
-static u64 releasable_read(struct cgroup *cgrp, struct cftype *cft)
+static u64 releasable_read(struct cgroup_subsys_state *css, struct cftype *cft)
{
- return test_bit(CGRP_RELEASABLE, &cgrp->flags);
+ return test_bit(CGRP_RELEASABLE, &css->cgroup->flags);
}
static struct cftype debug_files[] = {
projects / deliverable / linux.git / blobdiff