* @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,
*/
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
{
struct cgroup *cgrp = &root->top_cgroup;
struct cgroup_subsys *ss;
+ unsigned long pinned = 0;
int i, ret;
BUG_ON(!mutex_is_locked(&cgroup_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)
- return ret;
+ goto out_put;
/*
* Nothing can fail from this point on. Remove files for the
/* 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;
}
+ /* remounting is not allowed for populated hierarchies */
+ if (root->number_of_cgroups > 1) {
+ ret = -EBUSY;
+ goto out_unlock;
+ }
+
ret = rebind_subsystems(root, added_mask, removed_mask);
if (ret)
goto out_unlock;
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;
}
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);
}
}
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;
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))
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);
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);
struct task_and_cgroup {
struct task_struct *task;
struct cgroup *cgrp;
- struct css_set *cg;
+ struct css_set *cset;
};
struct cgroup_taskset {
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. */
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:
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;
}
* 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 *cgrp = __d_cgrp(cfe->dentry->d_parent);
+
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(cgrp, 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(cgrp, 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)
{
int err;
+ struct cfent *cfe;
struct cftype *cft;
err = generic_file_open(inode, file);
if (err)
return err;
- cft = __d_cft(file->f_dentry);
+ cfe = __d_cfe(file->f_dentry);
+ cft = cfe->type;
if (cft->read_map || cft->read_seq_string) {
- struct cgroup_seqfile_state *state;
-
- state = kzalloc(sizeof(*state), GFP_USER);
- if (!state)
- return -ENOMEM;
-
- state->cft = cft;
- state->cgroup = __d_cgrp(file->f_dentry->d_parent);
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;
+ }
return err;
}
* 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;
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)
{
int ret = 0;
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];
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;
}
}
+ idr_replace(&root->cgroup_idr, cgrp, cgrp->id);
+
err = cgroup_addrm_files(cgrp, NULL, cgroup_base_files, true);
if (err)
goto err_destroy;
/* 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:
/* 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);
/*
* 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);
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);