#include <linux/cred.h>
#include <linux/ctype.h>
#include <linux/errno.h>
-#include <linux/fs.h>
#include <linux/init_task.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/vmalloc.h> /* TODO: replace with more sophisticated array */
#include <linux/eventfd.h>
#include <linux/poll.h>
-#include <linux/flex_array.h> /* used in cgroup_attach_proc */
+#include <linux/flex_array.h> /* used in cgroup_attach_task */
#include <linux/kthread.h>
#include <linux/atomic.h>
* B happens only through cgroup_show_options() and using cgroup_root_mutex
* breaks it.
*/
+#ifdef CONFIG_PROVE_RCU
+DEFINE_MUTEX(cgroup_mutex);
+EXPORT_SYMBOL_GPL(cgroup_mutex); /* only for task_subsys_state_check() */
+#else
static DEFINE_MUTEX(cgroup_mutex);
+#endif
+
static DEFINE_MUTEX(cgroup_root_mutex);
/*
#include <linux/cgroup_subsys.h>
};
-#define MAX_CGROUP_ROOT_NAMELEN 64
-
-/*
- * A cgroupfs_root represents the root of a cgroup hierarchy,
- * and may be associated with a superblock to form an active
- * hierarchy
- */
-struct cgroupfs_root {
- struct super_block *sb;
-
- /*
- * The bitmask of subsystems intended to be attached to this
- * hierarchy
- */
- unsigned long subsys_mask;
-
- /* Unique id for this hierarchy. */
- int hierarchy_id;
-
- /* The bitmask of subsystems currently attached to this hierarchy */
- unsigned long actual_subsys_mask;
-
- /* A list running through the attached subsystems */
- struct list_head subsys_list;
-
- /* The root cgroup for this hierarchy */
- struct cgroup top_cgroup;
-
- /* Tracks how many cgroups are currently defined in hierarchy.*/
- int number_of_cgroups;
-
- /* A list running through the active hierarchies */
- struct list_head root_list;
-
- /* All cgroups on this root, cgroup_mutex protected */
- struct list_head allcg_list;
-
- /* Hierarchy-specific flags */
- unsigned long flags;
-
- /* IDs for cgroups in this hierarchy */
- struct ida cgroup_ida;
-
- /* The path to use for release notifications. */
- char release_agent_path[PATH_MAX];
-
- /* The name for this hierarchy - may be empty */
- char name[MAX_CGROUP_ROOT_NAMELEN];
-};
-
/*
* The "rootnode" hierarchy is the "dummy hierarchy", reserved for the
* subsystems that are otherwise unattached - it never has more than a
struct list_head node;
struct dentry *dentry;
struct cftype *type;
+
+ /* file xattrs */
+ struct simple_xattrs xattrs;
};
/*
/* dummytop is a shorthand for the dummy hierarchy's top cgroup */
#define dummytop (&rootnode.top_cgroup)
+static struct cgroup_name root_cgroup_name = { .name = "/" };
+
/* This flag indicates whether tasks in the fork and exit paths should
* check for fork/exit handlers to call. This avoids us having to do
* extra work in the fork/exit path if none of the subsystems need to
static int cgroup_addrm_files(struct cgroup *cgrp, struct cgroup_subsys *subsys,
struct cftype cfts[], bool is_add);
-#ifdef CONFIG_PROVE_LOCKING
-int cgroup_lock_is_held(void)
-{
- return lockdep_is_held(&cgroup_mutex);
-}
-#else /* #ifdef CONFIG_PROVE_LOCKING */
-int cgroup_lock_is_held(void)
-{
- return mutex_is_locked(&cgroup_mutex);
-}
-#endif /* #else #ifdef CONFIG_PROVE_LOCKING */
-
-EXPORT_SYMBOL_GPL(cgroup_lock_is_held);
-
static int css_unbias_refcnt(int refcnt)
{
return refcnt >= 0 ? refcnt : refcnt - CSS_DEACT_BIAS;
return test_bit(CGRP_REMOVED, &cgrp->flags);
}
-/* bits in struct cgroupfs_root flags field */
-enum {
- ROOT_NOPREFIX, /* mounted subsystems have no named prefix */
- ROOT_XATTR, /* supports extended attributes */
-};
+/**
+ * cgroup_is_descendant - test ancestry
+ * @cgrp: the cgroup to be tested
+ * @ancestor: possible ancestor of @cgrp
+ *
+ * Test whether @cgrp is a descendant of @ancestor. It also returns %true
+ * if @cgrp == @ancestor. This function is safe to call as long as @cgrp
+ * and @ancestor are accessible.
+ */
+bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor)
+{
+ while (cgrp) {
+ if (cgrp == ancestor)
+ return true;
+ cgrp = cgrp->parent;
+ }
+ return false;
+}
+EXPORT_SYMBOL_GPL(cgroup_is_descendant);
static int cgroup_is_releasable(const struct cgroup *cgrp)
{
return __d_cfe(dentry)->type;
}
+/**
+ * cgroup_lock_live_group - take cgroup_mutex and check that cgrp is alive.
+ * @cgrp: the cgroup to be checked for liveness
+ *
+ * On success, returns true; the mutex should be later unlocked. On
+ * failure returns false with no lock held.
+ */
+static bool cgroup_lock_live_group(struct cgroup *cgrp)
+{
+ mutex_lock(&cgroup_mutex);
+ if (cgroup_is_removed(cgrp)) {
+ mutex_unlock(&cgroup_mutex);
+ return false;
+ }
+ return true;
+}
+
/* the list of cgroups eligible for automatic release. Protected by
* release_list_lock */
static LIST_HEAD(release_list);
* update of a tasks cgroup pointer by cgroup_attach_task()
*/
-/**
- * cgroup_lock - lock out any changes to cgroup structures
- *
- */
-void cgroup_lock(void)
-{
- mutex_lock(&cgroup_mutex);
-}
-EXPORT_SYMBOL_GPL(cgroup_lock);
-
-/**
- * cgroup_unlock - release lock on cgroup changes
- *
- * Undo the lock taken in a previous cgroup_lock() call.
- */
-void cgroup_unlock(void)
-{
- mutex_unlock(&cgroup_mutex);
-}
-EXPORT_SYMBOL_GPL(cgroup_unlock);
-
/*
* A couple of forward declarations required, due to cyclic reference loop:
* cgroup_mkdir -> cgroup_create -> cgroup_populate_dir ->
return inode;
}
+static struct cgroup_name *cgroup_alloc_name(struct dentry *dentry)
+{
+ struct cgroup_name *name;
+
+ name = kmalloc(sizeof(*name) + dentry->d_name.len + 1, GFP_KERNEL);
+ if (!name)
+ return NULL;
+ strcpy(name->name, dentry->d_name.name);
+ return name;
+}
+
static void cgroup_free_fn(struct work_struct *work)
{
struct cgroup *cgrp = container_of(work, struct cgroup, free_work);
cgrp->root->number_of_cgroups--;
mutex_unlock(&cgroup_mutex);
+ /*
+ * We get a ref to the parent's dentry, and put the ref when
+ * this cgroup is being freed, so it's guaranteed that the
+ * parent won't be destroyed before its children.
+ */
+ 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
+ * created the cgroup. This will free cgrp->root, if we are
+ * holding the last reference to @sb.
*/
deactivate_super(cgrp->root->sb);
simple_xattrs_free(&cgrp->xattrs);
- ida_simple_remove(&cgrp->root->cgroup_ida, cgrp->id);
+ kfree(rcu_dereference_raw(cgrp->name));
kfree(cgrp);
}
} else {
struct cfent *cfe = __d_cfe(dentry);
struct cgroup *cgrp = dentry->d_parent->d_fsdata;
- struct cftype *cft = cfe->type;
WARN_ONCE(!list_empty(&cfe->node) &&
cgrp != &cgrp->root->top_cgroup,
"cfe still linked for %s\n", cfe->type->name);
+ simple_xattrs_free(&cfe->xattrs);
kfree(cfe);
- simple_xattrs_free(&cft->xattrs);
}
iput(inode);
}
mutex_lock(&cgroup_root_mutex);
for_each_subsys(root, ss)
seq_printf(seq, ",%s", ss->name);
- if (test_bit(ROOT_NOPREFIX, &root->flags))
+ if (root->flags & CGRP_ROOT_SANE_BEHAVIOR)
+ seq_puts(seq, ",sane_behavior");
+ if (root->flags & CGRP_ROOT_NOPREFIX)
seq_puts(seq, ",noprefix");
- if (test_bit(ROOT_XATTR, &root->flags))
+ if (root->flags & CGRP_ROOT_XATTR)
seq_puts(seq, ",xattr");
if (strlen(root->release_agent_path))
seq_printf(seq, ",release_agent=%s", root->release_agent_path);
all_ss = true;
continue;
}
+ if (!strcmp(token, "__DEVEL__sane_behavior")) {
+ opts->flags |= CGRP_ROOT_SANE_BEHAVIOR;
+ continue;
+ }
if (!strcmp(token, "noprefix")) {
- set_bit(ROOT_NOPREFIX, &opts->flags);
+ opts->flags |= CGRP_ROOT_NOPREFIX;
continue;
}
if (!strcmp(token, "clone_children")) {
continue;
}
if (!strcmp(token, "xattr")) {
- set_bit(ROOT_XATTR, &opts->flags);
+ opts->flags |= CGRP_ROOT_XATTR;
continue;
}
if (!strncmp(token, "release_agent=", 14)) {
/* Consistency checks */
+ if (opts->flags & CGRP_ROOT_SANE_BEHAVIOR) {
+ pr_warning("cgroup: sane_behavior: this is still under development and its behaviors will change, proceed at your own risk\n");
+
+ if (opts->flags & CGRP_ROOT_NOPREFIX) {
+ pr_err("cgroup: sane_behavior: noprefix is not allowed\n");
+ return -EINVAL;
+ }
+
+ if (opts->cpuset_clone_children) {
+ pr_err("cgroup: sane_behavior: clone_children is not allowed\n");
+ 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 (test_bit(ROOT_NOPREFIX, &opts->flags) &&
- (opts->subsys_mask & mask))
+ if ((opts->flags & CGRP_ROOT_NOPREFIX) && (opts->subsys_mask & mask))
return -EINVAL;
struct cgroup_sb_opts opts;
unsigned long added_mask, removed_mask;
+ if (root->flags & CGRP_ROOT_SANE_BEHAVIOR) {
+ pr_err("cgroup: sane_behavior: remount is not allowed\n");
+ return -EINVAL;
+ }
+
mutex_lock(&cgrp->dentry->d_inode->i_mutex);
mutex_lock(&cgroup_mutex);
mutex_lock(&cgroup_root_mutex);
INIT_LIST_HEAD(&root->allcg_list);
root->number_of_cgroups = 1;
cgrp->root = root;
- cgrp->top_cgroup = cgrp;
+ cgrp->name = &root_cgroup_name;
init_cgroup_housekeeping(cgrp);
list_add_tail(&cgrp->allcg_node, &root->allcg_list);
}
* any) is not needed
*/
cgroup_drop_root(opts.new_root);
+
+ if (((root->flags | opts.flags) & CGRP_ROOT_SANE_BEHAVIOR) &&
+ root->flags != opts.flags) {
+ pr_err("cgroup: sane_behavior: new mount options should match the existing superblock\n");
+ ret = -EINVAL;
+ goto drop_new_super;
+ }
+
/* no subsys rebinding, so refcounts don't change */
drop_parsed_module_refcounts(opts.subsys_mask);
}
* @buf: the buffer to write the path into
* @buflen: the length of the buffer
*
- * Called with cgroup_mutex held or else with an RCU-protected cgroup
- * reference. Writes path of cgroup into buf. Returns 0 on success,
- * -errno on error.
+ * Writes path of cgroup into buf. Returns 0 on success, -errno on error.
+ *
+ * We can't generate cgroup path using dentry->d_name, as accessing
+ * dentry->name must be protected by irq-unsafe dentry->d_lock or parent
+ * inode's i_mutex, while on the other hand cgroup_path() can be called
+ * with some irq-safe spinlocks held.
*/
int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen)
{
- struct dentry *dentry = cgrp->dentry;
+ int ret = -ENAMETOOLONG;
char *start;
- rcu_lockdep_assert(rcu_read_lock_held() || cgroup_lock_is_held(),
- "cgroup_path() called without proper locking");
-
- if (cgrp == dummytop) {
- /*
- * Inactive subsystems have no dentry for their root
- * cgroup
- */
- strcpy(buf, "/");
+ if (!cgrp->parent) {
+ if (strlcpy(buf, "/", buflen) >= buflen)
+ return -ENAMETOOLONG;
return 0;
}
start = buf + buflen - 1;
-
*start = '\0';
- for (;;) {
- int len = dentry->d_name.len;
+ rcu_read_lock();
+ do {
+ const char *name = cgroup_name(cgrp);
+ int len;
+
+ len = strlen(name);
if ((start -= len) < buf)
- return -ENAMETOOLONG;
- memcpy(start, dentry->d_name.name, len);
- cgrp = cgrp->parent;
- if (!cgrp)
- break;
+ goto out;
+ memcpy(start, name, len);
- dentry = cgrp->dentry;
- if (!cgrp->parent)
- continue;
if (--start < buf)
- return -ENAMETOOLONG;
+ goto out;
*start = '/';
- }
+
+ cgrp = cgrp->parent;
+ } while (cgrp->parent);
+ ret = 0;
memmove(buf, start, buf + buflen - start);
- return 0;
+out:
+ rcu_read_unlock();
+ return ret;
}
EXPORT_SYMBOL_GPL(cgroup_path);
*
* Must be called with cgroup_mutex and threadgroup locked.
*/
-static void cgroup_task_migrate(struct cgroup *cgrp, struct cgroup *oldcgrp,
+static void cgroup_task_migrate(struct cgroup *oldcgrp,
struct task_struct *tsk, struct css_set *newcg)
{
struct css_set *oldcg;
}
/**
- * cgroup_attach_task - attach task 'tsk' to cgroup 'cgrp'
- * @cgrp: the cgroup the task is attaching to
- * @tsk: the task to be attached
- *
- * Call with cgroup_mutex and threadgroup locked. May take task_lock of
- * @tsk during call.
- */
-int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
-{
- int retval = 0;
- struct cgroup_subsys *ss, *failed_ss = NULL;
- struct cgroup *oldcgrp;
- struct cgroupfs_root *root = cgrp->root;
- struct cgroup_taskset tset = { };
- struct css_set *newcg;
-
- /* @tsk either already exited or can't exit until the end */
- if (tsk->flags & PF_EXITING)
- return -ESRCH;
-
- /* Nothing to do if the task is already in that cgroup */
- oldcgrp = task_cgroup_from_root(tsk, root);
- if (cgrp == oldcgrp)
- return 0;
-
- tset.single.task = tsk;
- tset.single.cgrp = oldcgrp;
-
- for_each_subsys(root, ss) {
- if (ss->can_attach) {
- retval = ss->can_attach(cgrp, &tset);
- if (retval) {
- /*
- * Remember on which subsystem the can_attach()
- * failed, so that we only call cancel_attach()
- * against the subsystems whose can_attach()
- * succeeded. (See below)
- */
- failed_ss = ss;
- goto out;
- }
- }
- }
-
- newcg = find_css_set(tsk->cgroups, cgrp);
- if (!newcg) {
- retval = -ENOMEM;
- goto out;
- }
-
- cgroup_task_migrate(cgrp, oldcgrp, tsk, newcg);
-
- for_each_subsys(root, ss) {
- if (ss->attach)
- ss->attach(cgrp, &tset);
- }
-
-out:
- if (retval) {
- for_each_subsys(root, ss) {
- if (ss == failed_ss)
- /*
- * This subsystem was the one that failed the
- * can_attach() check earlier, so we don't need
- * to call cancel_attach() against it or any
- * remaining subsystems.
- */
- break;
- if (ss->cancel_attach)
- ss->cancel_attach(cgrp, &tset);
- }
- }
- return retval;
-}
-
-/**
- * cgroup_attach_task_all - attach task 'tsk' to all cgroups of task 'from'
- * @from: attach to all cgroups of a given task
- * @tsk: the task to be attached
- */
-int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk)
-{
- struct cgroupfs_root *root;
- int retval = 0;
-
- cgroup_lock();
- for_each_active_root(root) {
- struct cgroup *from_cg = task_cgroup_from_root(from, root);
-
- retval = cgroup_attach_task(from_cg, tsk);
- if (retval)
- break;
- }
- cgroup_unlock();
-
- return retval;
-}
-EXPORT_SYMBOL_GPL(cgroup_attach_task_all);
-
-/**
- * cgroup_attach_proc - attach all threads in a threadgroup to a cgroup
+ * cgroup_attach_task - attach a task or a whole threadgroup to a cgroup
* @cgrp: the cgroup to attach to
- * @leader: the threadgroup leader task_struct of the group to be attached
+ * @tsk: the task or the leader of the threadgroup to be attached
+ * @threadgroup: attach the whole threadgroup?
*
* Call holding cgroup_mutex and the group_rwsem of the leader. Will take
- * task_lock of each thread in leader's threadgroup individually in turn.
+ * task_lock of @tsk or each thread in the threadgroup individually in turn.
*/
-static int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
+static int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk,
+ bool threadgroup)
{
int retval, i, group_size;
struct cgroup_subsys *ss, *failed_ss = NULL;
- /* guaranteed to be initialized later, but the compiler needs this */
struct cgroupfs_root *root = cgrp->root;
/* threadgroup list cursor and array */
- struct task_struct *tsk;
+ struct task_struct *leader = tsk;
struct task_and_cgroup *tc;
struct flex_array *group;
struct cgroup_taskset tset = { };
* group - group_rwsem prevents new threads from appearing, and if
* threads exit, this will just be an over-estimate.
*/
- group_size = get_nr_threads(leader);
+ if (threadgroup)
+ group_size = get_nr_threads(tsk);
+ else
+ group_size = 1;
/* flex_array supports very large thread-groups better than kmalloc. */
group = flex_array_alloc(sizeof(*tc), group_size, GFP_KERNEL);
if (!group)
return -ENOMEM;
/* pre-allocate to guarantee space while iterating in rcu read-side. */
- retval = flex_array_prealloc(group, 0, group_size - 1, GFP_KERNEL);
+ retval = flex_array_prealloc(group, 0, group_size, GFP_KERNEL);
if (retval)
goto out_free_group_list;
- tsk = leader;
i = 0;
/*
* Prevent freeing of tasks while we take a snapshot. Tasks that are
retval = flex_array_put(group, i, &ent, GFP_ATOMIC);
BUG_ON(retval != 0);
i++;
+
+ if (!threadgroup)
+ break;
} while_each_thread(leader, tsk);
rcu_read_unlock();
/* remember the number of threads in the array for later. */
*/
for (i = 0; i < group_size; i++) {
tc = flex_array_get(group, i);
- cgroup_task_migrate(cgrp, tc->cgrp, tc->task, tc->cg);
+ cgroup_task_migrate(tc->cgrp, tc->task, tc->cg);
}
/* nothing is sensitive to fork() after this point. */
put_task_struct(tsk);
goto retry_find_task;
}
- ret = cgroup_attach_proc(cgrp, tsk);
- } else
- ret = cgroup_attach_task(cgrp, tsk);
+ }
+
+ ret = cgroup_attach_task(cgrp, tsk, threadgroup);
+
threadgroup_unlock(tsk);
put_task_struct(tsk);
out_unlock_cgroup:
- cgroup_unlock();
+ mutex_unlock(&cgroup_mutex);
return ret;
}
+/**
+ * cgroup_attach_task_all - attach task 'tsk' to all cgroups of task 'from'
+ * @from: attach to all cgroups of a given task
+ * @tsk: the task to be attached
+ */
+int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk)
+{
+ struct cgroupfs_root *root;
+ int retval = 0;
+
+ mutex_lock(&cgroup_mutex);
+ for_each_active_root(root) {
+ struct cgroup *from_cg = task_cgroup_from_root(from, root);
+
+ retval = cgroup_attach_task(from_cg, tsk, false);
+ if (retval)
+ break;
+ }
+ mutex_unlock(&cgroup_mutex);
+
+ return retval;
+}
+EXPORT_SYMBOL_GPL(cgroup_attach_task_all);
+
static int cgroup_tasks_write(struct cgroup *cgrp, struct cftype *cft, u64 pid)
{
return attach_task_by_pid(cgrp, pid, false);
return attach_task_by_pid(cgrp, tgid, true);
}
-/**
- * cgroup_lock_live_group - take cgroup_mutex and check that cgrp is alive.
- * @cgrp: the cgroup to be checked for liveness
- *
- * On success, returns true; the lock should be later released with
- * cgroup_unlock(). On failure returns false with no lock held.
- */
-bool cgroup_lock_live_group(struct cgroup *cgrp)
-{
- mutex_lock(&cgroup_mutex);
- if (cgroup_is_removed(cgrp)) {
- mutex_unlock(&cgroup_mutex);
- return false;
- }
- return true;
-}
-EXPORT_SYMBOL_GPL(cgroup_lock_live_group);
-
static int cgroup_release_agent_write(struct cgroup *cgrp, struct cftype *cft,
const char *buffer)
{
mutex_lock(&cgroup_root_mutex);
strcpy(cgrp->root->release_agent_path, buffer);
mutex_unlock(&cgroup_root_mutex);
- cgroup_unlock();
+ mutex_unlock(&cgroup_mutex);
return 0;
}
return -ENODEV;
seq_puts(seq, cgrp->root->release_agent_path);
seq_putc(seq, '\n');
- cgroup_unlock();
+ mutex_unlock(&cgroup_mutex);
+ return 0;
+}
+
+static int cgroup_sane_behavior_show(struct cgroup *cgrp, struct cftype *cft,
+ struct seq_file *seq)
+{
+ seq_printf(seq, "%d\n", cgroup_sane_behavior(cgrp));
return 0;
}
static int cgroup_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry)
{
+ int ret;
+ struct cgroup_name *name, *old_name;
+ struct cgroup *cgrp;
+
+ /*
+ * It's convinient to use parent dir's i_mutex to protected
+ * cgrp->name.
+ */
+ lockdep_assert_held(&old_dir->i_mutex);
+
if (!S_ISDIR(old_dentry->d_inode->i_mode))
return -ENOTDIR;
if (new_dentry->d_inode)
return -EEXIST;
if (old_dir != new_dir)
return -EIO;
- return simple_rename(old_dir, old_dentry, new_dir, new_dentry);
+
+ cgrp = __d_cgrp(old_dentry);
+
+ name = cgroup_alloc_name(new_dentry);
+ if (!name)
+ return -ENOMEM;
+
+ ret = simple_rename(old_dir, old_dentry, new_dir, new_dentry);
+ if (ret) {
+ kfree(name);
+ return ret;
+ }
+
+ old_name = cgrp->name;
+ rcu_assign_pointer(cgrp->name, name);
+
+ kfree_rcu(old_name, rcu_head);
+ return 0;
}
static struct simple_xattrs *__d_xattrs(struct dentry *dentry)
if (S_ISDIR(dentry->d_inode->i_mode))
return &__d_cgrp(dentry)->xattrs;
else
- return &__d_cft(dentry)->xattrs;
+ return &__d_cfe(dentry)->xattrs;
}
static inline int xattr_enabled(struct dentry *dentry)
{
struct cgroupfs_root *root = dentry->d_sb->s_fs_info;
- return test_bit(ROOT_XATTR, &root->flags);
+ return root->flags & CGRP_ROOT_XATTR;
}
static bool is_valid_xattr(const char *name)
umode_t mode;
char name[MAX_CGROUP_TYPE_NAMELEN + MAX_CFTYPE_NAME + 2] = { 0 };
- simple_xattrs_init(&cft->xattrs);
-
- if (subsys && !test_bit(ROOT_NOPREFIX, &cgrp->root->flags)) {
+ if (subsys && !(cgrp->root->flags & CGRP_ROOT_NOPREFIX)) {
strcpy(name, subsys->name);
strcat(name, ".");
}
cfe->type = (void *)cft;
cfe->dentry = dentry;
dentry->d_fsdata = cfe;
+ simple_xattrs_init(&cfe->xattrs);
list_add_tail(&cfe->node, &parent->files);
cfe = NULL;
}
for (cft = cfts; cft->name[0] != '\0'; cft++) {
/* does cft->flags tell us to skip this file on @cgrp? */
+ if ((cft->flags & CFTYPE_INSANE) && cgroup_sane_behavior(cgrp))
+ continue;
if ((cft->flags & CFTYPE_NOT_ON_ROOT) && !cgrp->parent)
continue;
if ((cft->flags & CFTYPE_ONLY_ON_ROOT) && cgrp->parent)
return 0;
}
+static void cgroup_transfer_one_task(struct task_struct *task,
+ struct cgroup_scanner *scan)
+{
+ struct cgroup *new_cgroup = scan->data;
+
+ mutex_lock(&cgroup_mutex);
+ cgroup_attach_task(new_cgroup, task, false);
+ mutex_unlock(&cgroup_mutex);
+}
+
+/**
+ * cgroup_trasnsfer_tasks - move tasks from one cgroup to another
+ * @to: cgroup to which the tasks will be moved
+ * @from: cgroup in which the tasks currently reside
+ */
+int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
+{
+ struct cgroup_scanner scan;
+
+ scan.cg = from;
+ scan.test_task = NULL; /* select all tasks in cgroup */
+ scan.process_task = cgroup_transfer_one_task;
+ scan.heap = NULL;
+ scan.data = to;
+
+ return cgroup_scan_tasks(&scan);
+}
+
/*
* Stuff for reading the 'tasks'/'procs' files.
*
else
kfree(p);
}
-static void *pidlist_resize(void *p, int newcount)
-{
- void *newlist;
- /* note: if new alloc fails, old p will still be valid either way */
- if (is_vmalloc_addr(p)) {
- newlist = vmalloc(newcount * sizeof(pid_t));
- if (!newlist)
- return NULL;
- memcpy(newlist, p, newcount * sizeof(pid_t));
- vfree(p);
- } else {
- newlist = krealloc(p, newcount * sizeof(pid_t), GFP_KERNEL);
- }
- return newlist;
-}
/*
* pidlist_uniq - given a kmalloc()ed list, strip out all duplicate entries
- * If the new stripped list is sufficiently smaller and there's enough memory
- * to allocate a new buffer, will let go of the unneeded memory. Returns the
- * number of unique elements.
+ * Returns the number of unique elements.
*/
-/* is the size difference enough that we should re-allocate the array? */
-#define PIDLIST_REALLOC_DIFFERENCE(old, new) ((old) - PAGE_SIZE >= (new))
-static int pidlist_uniq(pid_t **p, int length)
+static int pidlist_uniq(pid_t *list, int length)
{
int src, dest = 1;
- pid_t *list = *p;
- pid_t *newlist;
/*
* we presume the 0th element is unique, so i starts at 1. trivial
dest++;
}
after:
- /*
- * if the length difference is large enough, we want to allocate a
- * smaller buffer to save memory. if this fails due to out of memory,
- * we'll just stay with what we've got.
- */
- if (PIDLIST_REALLOC_DIFFERENCE(length, dest)) {
- newlist = pidlist_resize(list, dest);
- if (newlist)
- *p = newlist;
- }
return dest;
}
/* now sort & (if procs) strip out duplicates */
sort(array, length, sizeof(pid_t), cmppid, NULL);
if (type == CGROUP_FILE_PROCS)
- length = pidlist_uniq(&array, length);
+ length = pidlist_uniq(array, length);
l = cgroup_pidlist_find(cgrp, type);
if (!l) {
pidlist_free(array);
if (ret)
goto fail;
- if (efile->f_op->poll(efile, &event->pt) & POLLHUP) {
- event->cft->unregister_event(cgrp, event->cft, event->eventfd);
- ret = 0;
- goto fail;
- }
+ efile->f_op->poll(efile, &event->pt);
/*
* Events should be removed after rmdir of cgroup directory, but before
},
{
.name = "cgroup.clone_children",
+ .flags = CFTYPE_INSANE,
.read_u64 = cgroup_clone_children_read,
.write_u64 = cgroup_clone_children_write,
},
+ {
+ .name = "cgroup.sane_behavior",
+ .flags = CFTYPE_ONLY_ON_ROOT,
+ .read_seq_string = cgroup_sane_behavior_show,
+ },
{
.name = "release_agent",
.flags = CFTYPE_ONLY_ON_ROOT,
if (!(css->flags & CSS_ONLINE))
return;
- /*
- * css_offline() should be called with cgroup_mutex unlocked. See
- * 3fa59dfbc3 ("cgroup: fix potential deadlock in pre_destroy") for
- * details. This temporary unlocking should go away once
- * cgroup_mutex is unexported from controllers.
- */
- if (ss->css_offline) {
- mutex_unlock(&cgroup_mutex);
+ if (ss->css_offline)
ss->css_offline(cgrp);
- mutex_lock(&cgroup_mutex);
- }
cgrp->subsys[ss->subsys_id]->flags &= ~CSS_ONLINE;
}
umode_t mode)
{
struct cgroup *cgrp;
+ struct cgroup_name *name;
struct cgroupfs_root *root = parent->root;
int err = 0;
struct cgroup_subsys *ss;
if (!cgrp)
return -ENOMEM;
+ name = cgroup_alloc_name(dentry);
+ if (!name)
+ goto err_free_cgrp;
+ rcu_assign_pointer(cgrp->name, name);
+
cgrp->id = ida_simple_get(&root->cgroup_ida, 1, 0, GFP_KERNEL);
if (cgrp->id < 0)
- goto err_free_cgrp;
+ goto err_free_name;
/*
* Only live parents can have children. Note that the liveliness
cgrp->parent = parent;
cgrp->root = parent->root;
- cgrp->top_cgroup = parent->top_cgroup;
if (notify_on_release(parent))
set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
for_each_subsys(root, ss)
dget(dentry);
+ /* hold a ref to the parent's dentry */
+ dget(parent->dentry);
+
/* creation succeeded, notify subsystems */
for_each_subsys(root, ss) {
err = online_css(ss, cgrp);
deactivate_super(sb);
err_free_id:
ida_simple_remove(&root->cgroup_ida, cgrp->id);
+err_free_name:
+ kfree(rcu_dereference_raw(cgrp->name));
err_free_cgrp:
kfree(cgrp);
return err;
return cgroup_create(c_parent, dentry, mode | S_IFDIR);
}
-/*
- * Check the reference count on each subsystem. Since we already
- * established that there are no tasks in the cgroup, if the css refcount
- * is also 1, then there should be no outstanding references, so the
- * subsystem is safe to destroy. We scan across all subsystems rather than
- * using the per-hierarchy linked list of mounted subsystems since we can
- * be called via check_for_release() with no synchronization other than
- * RCU, and the subsystem linked list isn't RCU-safe.
- */
-static int cgroup_has_css_refs(struct cgroup *cgrp)
-{
- int i;
-
- /*
- * We won't need to lock the subsys array, because the subsystems
- * we're concerned about aren't going anywhere since our cgroup root
- * has a reference on them.
- */
- for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
- struct cgroup_subsys *ss = subsys[i];
- struct cgroup_subsys_state *css;
-
- /* Skip subsystems not present or not in this hierarchy */
- if (ss == NULL || ss->root != cgrp->root)
- continue;
-
- css = cgrp->subsys[ss->subsys_id];
- /*
- * When called from check_for_release() it's possible
- * that by this point the cgroup has been removed
- * and the css deleted. But a false-positive doesn't
- * matter, since it can only happen if the cgroup
- * has been deleted and hence no longer needs the
- * release agent to be called anyway.
- */
- if (css && css_refcnt(css) > 1)
- return 1;
- }
- return 0;
-}
-
static int cgroup_destroy_locked(struct cgroup *cgrp)
__releases(&cgroup_mutex) __acquires(&cgroup_mutex)
{
struct dentry *d = cgrp->dentry;
struct cgroup *parent = cgrp->parent;
- DEFINE_WAIT(wait);
struct cgroup_event *event, *tmp;
struct cgroup_subsys *ss;
- LIST_HEAD(tmp_list);
lockdep_assert_held(&d->d_inode->i_mutex);
lockdep_assert_held(&cgroup_mutex);
* and addition to css_set.
*/
if (need_forkexit_callback) {
- for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
+ /*
+ * fork/exit callbacks are supported only for builtin
+ * subsystems, and the builtin section of the subsys
+ * array is immutable, so we don't need to lock the
+ * subsys array here. On the other hand, modular section
+ * of the array can be freed at module unload, so we
+ * can't touch that.
+ */
+ for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
- /*
- * fork/exit callbacks are supported only for
- * builtin subsystems and we don't need further
- * synchronization as they never go away.
- */
- if (!ss || ss->module)
- continue;
-
if (ss->fork)
ss->fork(child);
}
tsk->cgroups = &init_css_set;
if (run_callbacks && need_forkexit_callback) {
- for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
+ /*
+ * fork/exit callbacks are supported only for builtin
+ * subsystems, see cgroup_post_fork() for details.
+ */
+ for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
- /* modular subsystems can't use callbacks */
- if (!ss || ss->module)
- continue;
-
if (ss->exit) {
struct cgroup *old_cgrp =
rcu_dereference_raw(cg->subsys[i])->cgroup;
put_css_set_taskexit(cg);
}
-/**
- * cgroup_is_descendant - see if @cgrp is a descendant of @task's cgrp
- * @cgrp: the cgroup in question
- * @task: the task in question
- *
- * See if @cgrp is a descendant of @task's cgroup in the appropriate
- * hierarchy.
- *
- * If we are sending in dummytop, then presumably we are creating
- * the top cgroup in the subsystem.
- *
- * Called only by the ns (nsproxy) cgroup.
- */
-int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task)
-{
- int ret;
- struct cgroup *target;
-
- if (cgrp == dummytop)
- return 1;
-
- target = task_cgroup_from_root(task, cgrp->root);
- while (cgrp != target && cgrp!= cgrp->top_cgroup)
- cgrp = cgrp->parent;
- ret = (cgrp == target);
- return ret;
-}
-
static void check_for_release(struct cgroup *cgrp)
{
/* All of these checks rely on RCU to keep the cgroup
* structure alive */
- if (cgroup_is_releasable(cgrp) && !atomic_read(&cgrp->count)
- && list_empty(&cgrp->children) && !cgroup_has_css_refs(cgrp)) {
- /* Control Group is currently removeable. If it's not
+ if (cgroup_is_releasable(cgrp) &&
+ !atomic_read(&cgrp->count) && list_empty(&cgrp->children)) {
+ /*
+ * Control Group is currently removeable. If it's not
* already queued for a userspace notification, queue
- * it now */
+ * it now
+ */
int need_schedule_work = 0;
+
raw_spin_lock(&release_list_lock);
if (!cgroup_is_removed(cgrp) &&
list_empty(&cgrp->release_list)) {
/* Caller must verify that the css is not for root cgroup */
void __css_put(struct cgroup_subsys_state *css)
{
- struct cgroup *cgrp = css->cgroup;
int v;
- rcu_read_lock();
v = css_unbias_refcnt(atomic_dec_return(&css->refcnt));
-
- switch (v) {
- case 1:
- if (notify_on_release(cgrp)) {
- set_bit(CGRP_RELEASABLE, &cgrp->flags);
- check_for_release(cgrp);
- }
- break;
- case 0:
+ if (v == 0)
schedule_work(&css->dput_work);
- break;
- }
- rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(__css_put);
projects / ~andy / linux / blobdiff