1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __CGROUP_INTERNAL_H 3 #define __CGROUP_INTERNAL_H 4 5 #include <linux/cgroup.h> 6 #include <linux/kernfs.h> 7 #include <linux/workqueue.h> 8 #include <linux/list.h> 9 #include <linux/refcount.h> 10 11 /* 12 * A cgroup can be associated with multiple css_sets as different tasks may 13 * belong to different cgroups on different hierarchies. In the other 14 * direction, a css_set is naturally associated with multiple cgroups. 15 * This M:N relationship is represented by the following link structure 16 * which exists for each association and allows traversing the associations 17 * from both sides. 18 */ 19 struct cgrp_cset_link { 20 /* the cgroup and css_set this link associates */ 21 struct cgroup *cgrp; 22 struct css_set *cset; 23 24 /* list of cgrp_cset_links anchored at cgrp->cset_links */ 25 struct list_head cset_link; 26 27 /* list of cgrp_cset_links anchored at css_set->cgrp_links */ 28 struct list_head cgrp_link; 29 }; 30 31 /* used to track tasks and csets during migration */ 32 struct cgroup_taskset { 33 /* the src and dst cset list running through cset->mg_node */ 34 struct list_head src_csets; 35 struct list_head dst_csets; 36 37 /* the number of tasks in the set */ 38 int nr_tasks; 39 40 /* the subsys currently being processed */ 41 int ssid; 42 43 /* 44 * Fields for cgroup_taskset_*() iteration. 45 * 46 * Before migration is committed, the target migration tasks are on 47 * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of 48 * the csets on ->dst_csets. ->csets point to either ->src_csets 49 * or ->dst_csets depending on whether migration is committed. 50 * 51 * ->cur_csets and ->cur_task point to the current task position 52 * during iteration. 53 */ 54 struct list_head *csets; 55 struct css_set *cur_cset; 56 struct task_struct *cur_task; 57 }; 58 59 /* migration context also tracks preloading */ 60 struct cgroup_mgctx { 61 /* 62 * Preloaded source and destination csets. Used to guarantee 63 * atomic success or failure on actual migration. 64 */ 65 struct list_head preloaded_src_csets; 66 struct list_head preloaded_dst_csets; 67 68 /* tasks and csets to migrate */ 69 struct cgroup_taskset tset; 70 71 /* subsystems affected by migration */ 72 u16 ss_mask; 73 }; 74 75 #define CGROUP_TASKSET_INIT(tset) \ 76 { \ 77 .src_csets = LIST_HEAD_INIT(tset.src_csets), \ 78 .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \ 79 .csets = &tset.src_csets, \ 80 } 81 82 #define CGROUP_MGCTX_INIT(name) \ 83 { \ 84 LIST_HEAD_INIT(name.preloaded_src_csets), \ 85 LIST_HEAD_INIT(name.preloaded_dst_csets), \ 86 CGROUP_TASKSET_INIT(name.tset), \ 87 } 88 89 #define DEFINE_CGROUP_MGCTX(name) \ 90 struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name) 91 92 struct cgroup_sb_opts { 93 u16 subsys_mask; 94 unsigned int flags; 95 char *release_agent; 96 bool cpuset_clone_children; 97 char *name; 98 /* User explicitly requested empty subsystem */ 99 bool none; 100 }; 101 102 extern struct mutex cgroup_mutex; 103 extern spinlock_t css_set_lock; 104 extern struct cgroup_subsys *cgroup_subsys[]; 105 extern struct list_head cgroup_roots; 106 extern struct file_system_type cgroup_fs_type; 107 108 /* iterate across the hierarchies */ 109 #define for_each_root(root) \ 110 list_for_each_entry((root), &cgroup_roots, root_list) 111 112 /** 113 * for_each_subsys - iterate all enabled cgroup subsystems 114 * @ss: the iteration cursor 115 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end 116 */ 117 #define for_each_subsys(ss, ssid) \ 118 for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \ 119 (((ss) = cgroup_subsys[ssid]) || true); (ssid)++) 120 121 static inline bool cgroup_is_dead(const struct cgroup *cgrp) 122 { 123 return !(cgrp->self.flags & CSS_ONLINE); 124 } 125 126 static inline bool notify_on_release(const struct cgroup *cgrp) 127 { 128 return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); 129 } 130 131 void put_css_set_locked(struct css_set *cset); 132 133 static inline void put_css_set(struct css_set *cset) 134 { 135 unsigned long flags; 136 137 /* 138 * Ensure that the refcount doesn't hit zero while any readers 139 * can see it. Similar to atomic_dec_and_lock(), but for an 140 * rwlock 141 */ 142 if (refcount_dec_not_one(&cset->refcount)) 143 return; 144 145 spin_lock_irqsave(&css_set_lock, flags); 146 put_css_set_locked(cset); 147 spin_unlock_irqrestore(&css_set_lock, flags); 148 } 149 150 /* 151 * refcounted get/put for css_set objects 152 */ 153 static inline void get_css_set(struct css_set *cset) 154 { 155 refcount_inc(&cset->refcount); 156 } 157 158 bool cgroup_ssid_enabled(int ssid); 159 bool cgroup_on_dfl(const struct cgroup *cgrp); 160 bool cgroup_is_thread_root(struct cgroup *cgrp); 161 bool cgroup_is_threaded(struct cgroup *cgrp); 162 163 struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root); 164 struct cgroup *task_cgroup_from_root(struct task_struct *task, 165 struct cgroup_root *root); 166 struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline); 167 void cgroup_kn_unlock(struct kernfs_node *kn); 168 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen, 169 struct cgroup_namespace *ns); 170 171 void cgroup_free_root(struct cgroup_root *root); 172 void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts); 173 int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags); 174 int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask); 175 struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, 176 struct cgroup_root *root, unsigned long magic, 177 struct cgroup_namespace *ns); 178 179 int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp); 180 void cgroup_migrate_finish(struct cgroup_mgctx *mgctx); 181 void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp, 182 struct cgroup_mgctx *mgctx); 183 int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx); 184 int cgroup_migrate(struct task_struct *leader, bool threadgroup, 185 struct cgroup_mgctx *mgctx); 186 187 int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, 188 bool threadgroup); 189 struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup) 190 __acquires(&cgroup_threadgroup_rwsem); 191 void cgroup_procs_write_finish(struct task_struct *task) 192 __releases(&cgroup_threadgroup_rwsem); 193 194 void cgroup_lock_and_drain_offline(struct cgroup *cgrp); 195 196 int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode); 197 int cgroup_rmdir(struct kernfs_node *kn); 198 int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, 199 struct kernfs_root *kf_root); 200 201 int cgroup_task_count(const struct cgroup *cgrp); 202 203 /* 204 * rstat.c 205 */ 206 int cgroup_rstat_init(struct cgroup *cgrp); 207 void cgroup_rstat_exit(struct cgroup *cgrp); 208 void cgroup_rstat_boot(void); 209 void cgroup_base_stat_cputime_show(struct seq_file *seq); 210 211 /* 212 * namespace.c 213 */ 214 extern const struct proc_ns_operations cgroupns_operations; 215 216 /* 217 * cgroup-v1.c 218 */ 219 extern struct cftype cgroup1_base_files[]; 220 extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops; 221 222 int proc_cgroupstats_show(struct seq_file *m, void *v); 223 bool cgroup1_ssid_disabled(int ssid); 224 void cgroup1_pidlist_destroy_all(struct cgroup *cgrp); 225 void cgroup1_release_agent(struct work_struct *work); 226 void cgroup1_check_for_release(struct cgroup *cgrp); 227 struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags, 228 void *data, unsigned long magic, 229 struct cgroup_namespace *ns); 230 231 #endif /* __CGROUP_INTERNAL_H */ 232