diff options
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 126 |
1 files changed, 103 insertions, 23 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index f89d9292eee6..f3f5cd5e2c0d 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -107,8 +107,8 @@ static DEFINE_SPINLOCK(release_agent_path_lock); struct percpu_rw_semaphore cgroup_threadgroup_rwsem; #define cgroup_assert_mutex_or_rcu_locked() \ - rcu_lockdep_assert(rcu_read_lock_held() || \ - lockdep_is_held(&cgroup_mutex), \ + RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \ + !lockdep_is_held(&cgroup_mutex), \ "cgroup_mutex or RCU read lock required"); /* @@ -145,6 +145,7 @@ static const char *cgroup_subsys_name[] = { * part of that cgroup. */ struct cgroup_root cgrp_dfl_root; +EXPORT_SYMBOL_GPL(cgrp_dfl_root); /* * The default hierarchy always exists but is hidden until mounted for the @@ -186,6 +187,9 @@ static u64 css_serial_nr_next = 1; static unsigned long have_fork_callback __read_mostly; static unsigned long have_exit_callback __read_mostly; +/* Ditto for the can_fork callback. */ +static unsigned long have_canfork_callback __read_mostly; + static struct cftype cgroup_dfl_base_files[]; static struct cftype cgroup_legacy_base_files[]; @@ -207,7 +211,7 @@ static int cgroup_idr_alloc(struct idr *idr, void *ptr, int start, int end, idr_preload(gfp_mask); spin_lock_bh(&cgroup_idr_lock); - ret = idr_alloc(idr, ptr, start, end, gfp_mask); + ret = idr_alloc(idr, ptr, start, end, gfp_mask & ~__GFP_WAIT); spin_unlock_bh(&cgroup_idr_lock); idr_preload_end(); return ret; @@ -1027,10 +1031,13 @@ static const struct file_operations proc_cgroupstats_operations; static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft, char *buf) { + struct cgroup_subsys *ss = cft->ss; + if (cft->ss && !(cft->flags & CFTYPE_NO_PREFIX) && !(cgrp->root->flags & CGRP_ROOT_NOPREFIX)) snprintf(buf, CGROUP_FILE_NAME_MAX, "%s.%s", - cft->ss->name, cft->name); + cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name, + cft->name); else strncpy(buf, cft->name, CGROUP_FILE_NAME_MAX); return buf; @@ -1332,9 +1339,10 @@ static int cgroup_show_options(struct seq_file *seq, struct cgroup_subsys *ss; int ssid; - for_each_subsys(ss, ssid) - if (root->subsys_mask & (1 << ssid)) - seq_printf(seq, ",%s", ss->name); + if (root != &cgrp_dfl_root) + for_each_subsys(ss, ssid) + if (root->subsys_mask & (1 << ssid)) + seq_printf(seq, ",%s", ss->legacy_name); if (root->flags & CGRP_ROOT_NOPREFIX) seq_puts(seq, ",noprefix"); if (root->flags & CGRP_ROOT_XATTR) @@ -1447,7 +1455,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) } for_each_subsys(ss, i) { - if (strcmp(token, ss->name)) + if (strcmp(token, ss->legacy_name)) continue; if (ss->disabled) continue; @@ -1666,7 +1674,7 @@ static int cgroup_setup_root(struct cgroup_root *root, unsigned long ss_mask) lockdep_assert_held(&cgroup_mutex); - ret = cgroup_idr_alloc(&root->cgroup_idr, root_cgrp, 1, 2, GFP_NOWAIT); + ret = cgroup_idr_alloc(&root->cgroup_idr, root_cgrp, 1, 2, GFP_KERNEL); if (ret < 0) goto out; root_cgrp->id = ret; @@ -4579,7 +4587,7 @@ static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss, if (err) goto err_free_css; - err = cgroup_idr_alloc(&ss->css_idr, NULL, 2, 0, GFP_NOWAIT); + err = cgroup_idr_alloc(&ss->css_idr, NULL, 2, 0, GFP_KERNEL); if (err < 0) goto err_free_percpu_ref; css->id = err; @@ -4656,7 +4664,7 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, * Temporarily set the pointer to NULL, so idr_find() won't return * a half-baked cgroup. */ - cgrp->id = cgroup_idr_alloc(&root->cgroup_idr, NULL, 2, 0, GFP_NOWAIT); + cgrp->id = cgroup_idr_alloc(&root->cgroup_idr, NULL, 2, 0, GFP_KERNEL); if (cgrp->id < 0) { ret = -ENOMEM; goto out_cancel_ref; @@ -4955,6 +4963,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early) have_fork_callback |= (bool)ss->fork << ss->id; have_exit_callback |= (bool)ss->exit << ss->id; + have_canfork_callback |= (bool)ss->can_fork << ss->id; /* At system boot, before all subsystems have been * registered, no tasks have been forked, so we don't @@ -4993,6 +5002,8 @@ int __init cgroup_init_early(void) ss->id = i; ss->name = cgroup_subsys_name[i]; + if (!ss->legacy_name) + ss->legacy_name = cgroup_subsys_name[i]; if (ss->early_init) cgroup_init_subsys(ss, true); @@ -5136,9 +5147,11 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, continue; seq_printf(m, "%d:", root->hierarchy_id); - for_each_subsys(ss, ssid) - if (root->subsys_mask & (1 << ssid)) - seq_printf(m, "%s%s", count++ ? "," : "", ss->name); + if (root != &cgrp_dfl_root) + for_each_subsys(ss, ssid) + if (root->subsys_mask & (1 << ssid)) + seq_printf(m, "%s%s", count++ ? "," : "", + ss->legacy_name); if (strlen(root->name)) seq_printf(m, "%sname=%s", count ? "," : "", root->name); @@ -5178,7 +5191,7 @@ static int proc_cgroupstats_show(struct seq_file *m, void *v) for_each_subsys(ss, i) seq_printf(m, "%s\t%d\t%d\t%d\n", - ss->name, ss->root->hierarchy_id, + ss->legacy_name, ss->root->hierarchy_id, atomic_read(&ss->root->nr_cgrps), !ss->disabled); mutex_unlock(&cgroup_mutex); @@ -5197,6 +5210,19 @@ static const struct file_operations proc_cgroupstats_operations = { .release = single_release, }; +static void **subsys_canfork_priv_p(void *ss_priv[CGROUP_CANFORK_COUNT], int i) +{ + if (CGROUP_CANFORK_START <= i && i < CGROUP_CANFORK_END) + return &ss_priv[i - CGROUP_CANFORK_START]; + return NULL; +} + +static void *subsys_canfork_priv(void *ss_priv[CGROUP_CANFORK_COUNT], int i) +{ + void **private = subsys_canfork_priv_p(ss_priv, i); + return private ? *private : NULL; +} + /** * cgroup_fork - initialize cgroup related fields during copy_process() * @child: pointer to task_struct of forking parent process. @@ -5212,6 +5238,57 @@ void cgroup_fork(struct task_struct *child) } /** + * cgroup_can_fork - called on a new task before the process is exposed + * @child: the task in question. + * + * This calls the subsystem can_fork() callbacks. If the can_fork() callback + * returns an error, the fork aborts with that error code. This allows for + * a cgroup subsystem to conditionally allow or deny new forks. + */ +int cgroup_can_fork(struct task_struct *child, + void *ss_priv[CGROUP_CANFORK_COUNT]) +{ + struct cgroup_subsys *ss; + int i, j, ret; + + for_each_subsys_which(ss, i, &have_canfork_callback) { + ret = ss->can_fork(child, subsys_canfork_priv_p(ss_priv, i)); + if (ret) + goto out_revert; + } + + return 0; + +out_revert: + for_each_subsys(ss, j) { + if (j >= i) + break; + if (ss->cancel_fork) + ss->cancel_fork(child, subsys_canfork_priv(ss_priv, j)); + } + + return ret; +} + +/** + * cgroup_cancel_fork - called if a fork failed after cgroup_can_fork() + * @child: the task in question + * + * This calls the cancel_fork() callbacks if a fork failed *after* + * cgroup_can_fork() succeded. + */ +void cgroup_cancel_fork(struct task_struct *child, + void *ss_priv[CGROUP_CANFORK_COUNT]) +{ + struct cgroup_subsys *ss; + int i; + + for_each_subsys(ss, i) + if (ss->cancel_fork) + ss->cancel_fork(child, subsys_canfork_priv(ss_priv, i)); +} + +/** * cgroup_post_fork - called on a new task after adding it to the task list * @child: the task in question * @@ -5221,7 +5298,8 @@ void cgroup_fork(struct task_struct *child) * cgroup_task_iter_start() - to guarantee that the new task ends up on its * list. */ -void cgroup_post_fork(struct task_struct *child) +void cgroup_post_fork(struct task_struct *child, + void *old_ss_priv[CGROUP_CANFORK_COUNT]) { struct cgroup_subsys *ss; int i; @@ -5266,7 +5344,7 @@ void cgroup_post_fork(struct task_struct *child) * and addition to css_set. */ for_each_subsys_which(ss, i, &have_fork_callback) - ss->fork(child); + ss->fork(child, subsys_canfork_priv(old_ss_priv, i)); } /** @@ -5400,12 +5478,14 @@ static int __init cgroup_disable(char *str) continue; for_each_subsys(ss, i) { - if (!strcmp(token, ss->name)) { - ss->disabled = 1; - printk(KERN_INFO "Disabling %s control group" - " subsystem\n", ss->name); - break; - } + if (strcmp(token, ss->name) && + strcmp(token, ss->legacy_name)) + continue; + + ss->disabled = 1; + printk(KERN_INFO "Disabling %s control group subsystem\n", + ss->name); + break; } } return 1; |