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 #include <linux/fs_context.h> 11 12 #define TRACE_CGROUP_PATH_LEN 1024 13 extern spinlock_t trace_cgroup_path_lock; 14 extern char trace_cgroup_path[TRACE_CGROUP_PATH_LEN]; 15 extern bool cgroup_debug; 16 extern void __init enable_debug_cgroup(void); 17 18 /* 19 * cgroup_path() takes a spin lock. It is good practice not to take 20 * spin locks within trace point handlers, as they are mostly hidden 21 * from normal view. As cgroup_path() can take the kernfs_rename_lock 22 * spin lock, it is best to not call that function from the trace event 23 * handler. 24 * 25 * Note: trace_cgroup_##type##_enabled() is a static branch that will only 26 * be set when the trace event is enabled. 27 */ 28 #define TRACE_CGROUP_PATH(type, cgrp, ...) \ 29 do { \ 30 if (trace_cgroup_##type##_enabled()) { \ 31 unsigned long flags; \ 32 spin_lock_irqsave(&trace_cgroup_path_lock, \ 33 flags); \ 34 cgroup_path(cgrp, trace_cgroup_path, \ 35 TRACE_CGROUP_PATH_LEN); \ 36 trace_cgroup_##type(cgrp, trace_cgroup_path, \ 37 ##__VA_ARGS__); \ 38 spin_unlock_irqrestore(&trace_cgroup_path_lock, \ 39 flags); \ 40 } \ 41 } while (0) 42 43 /* 44 * The cgroup filesystem superblock creation/mount context. 45 */ 46 struct cgroup_fs_context { 47 struct kernfs_fs_context kfc; 48 struct cgroup_root *root; 49 struct cgroup_namespace *ns; 50 unsigned int flags; /* CGRP_ROOT_* flags */ 51 52 /* cgroup1 bits */ 53 bool cpuset_clone_children; 54 bool none; /* User explicitly requested empty subsystem */ 55 bool all_ss; /* Seen 'all' option */ 56 u16 subsys_mask; /* Selected subsystems */ 57 char *name; /* Hierarchy name */ 58 char *release_agent; /* Path for release notifications */ 59 }; 60 61 static inline struct cgroup_fs_context *cgroup_fc2context(struct fs_context *fc) 62 { 63 struct kernfs_fs_context *kfc = fc->fs_private; 64 65 return container_of(kfc, struct cgroup_fs_context, kfc); 66 } 67 68 /* 69 * A cgroup can be associated with multiple css_sets as different tasks may 70 * belong to different cgroups on different hierarchies. In the other 71 * direction, a css_set is naturally associated with multiple cgroups. 72 * This M:N relationship is represented by the following link structure 73 * which exists for each association and allows traversing the associations 74 * from both sides. 75 */ 76 struct cgrp_cset_link { 77 /* the cgroup and css_set this link associates */ 78 struct cgroup *cgrp; 79 struct css_set *cset; 80 81 /* list of cgrp_cset_links anchored at cgrp->cset_links */ 82 struct list_head cset_link; 83 84 /* list of cgrp_cset_links anchored at css_set->cgrp_links */ 85 struct list_head cgrp_link; 86 }; 87 88 /* used to track tasks and csets during migration */ 89 struct cgroup_taskset { 90 /* the src and dst cset list running through cset->mg_node */ 91 struct list_head src_csets; 92 struct list_head dst_csets; 93 94 /* the number of tasks in the set */ 95 int nr_tasks; 96 97 /* the subsys currently being processed */ 98 int ssid; 99 100 /* 101 * Fields for cgroup_taskset_*() iteration. 102 * 103 * Before migration is committed, the target migration tasks are on 104 * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of 105 * the csets on ->dst_csets. ->csets point to either ->src_csets 106 * or ->dst_csets depending on whether migration is committed. 107 * 108 * ->cur_csets and ->cur_task point to the current task position 109 * during iteration. 110 */ 111 struct list_head *csets; 112 struct css_set *cur_cset; 113 struct task_struct *cur_task; 114 }; 115 116 /* migration context also tracks preloading */ 117 struct cgroup_mgctx { 118 /* 119 * Preloaded source and destination csets. Used to guarantee 120 * atomic success or failure on actual migration. 121 */ 122 struct list_head preloaded_src_csets; 123 struct list_head preloaded_dst_csets; 124 125 /* tasks and csets to migrate */ 126 struct cgroup_taskset tset; 127 128 /* subsystems affected by migration */ 129 u16 ss_mask; 130 }; 131 132 #define CGROUP_TASKSET_INIT(tset) \ 133 { \ 134 .src_csets = LIST_HEAD_INIT(tset.src_csets), \ 135 .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \ 136 .csets = &tset.src_csets, \ 137 } 138 139 #define CGROUP_MGCTX_INIT(name) \ 140 { \ 141 LIST_HEAD_INIT(name.preloaded_src_csets), \ 142 LIST_HEAD_INIT(name.preloaded_dst_csets), \ 143 CGROUP_TASKSET_INIT(name.tset), \ 144 } 145 146 #define DEFINE_CGROUP_MGCTX(name) \ 147 struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name) 148 149 extern struct mutex cgroup_mutex; 150 extern spinlock_t css_set_lock; 151 extern struct cgroup_subsys *cgroup_subsys[]; 152 extern struct list_head cgroup_roots; 153 extern struct file_system_type cgroup_fs_type; 154 155 /* iterate across the hierarchies */ 156 #define for_each_root(root) \ 157 list_for_each_entry((root), &cgroup_roots, root_list) 158 159 /** 160 * for_each_subsys - iterate all enabled cgroup subsystems 161 * @ss: the iteration cursor 162 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end 163 */ 164 #define for_each_subsys(ss, ssid) \ 165 for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \ 166 (((ss) = cgroup_subsys[ssid]) || true); (ssid)++) 167 168 static inline bool cgroup_is_dead(const struct cgroup *cgrp) 169 { 170 return !(cgrp->self.flags & CSS_ONLINE); 171 } 172 173 static inline bool notify_on_release(const struct cgroup *cgrp) 174 { 175 return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); 176 } 177 178 void put_css_set_locked(struct css_set *cset); 179 180 static inline void put_css_set(struct css_set *cset) 181 { 182 unsigned long flags; 183 184 /* 185 * Ensure that the refcount doesn't hit zero while any readers 186 * can see it. Similar to atomic_dec_and_lock(), but for an 187 * rwlock 188 */ 189 if (refcount_dec_not_one(&cset->refcount)) 190 return; 191 192 spin_lock_irqsave(&css_set_lock, flags); 193 put_css_set_locked(cset); 194 spin_unlock_irqrestore(&css_set_lock, flags); 195 } 196 197 /* 198 * refcounted get/put for css_set objects 199 */ 200 static inline void get_css_set(struct css_set *cset) 201 { 202 refcount_inc(&cset->refcount); 203 } 204 205 bool cgroup_ssid_enabled(int ssid); 206 bool cgroup_on_dfl(const struct cgroup *cgrp); 207 bool cgroup_is_thread_root(struct cgroup *cgrp); 208 bool cgroup_is_threaded(struct cgroup *cgrp); 209 210 struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root); 211 struct cgroup *task_cgroup_from_root(struct task_struct *task, 212 struct cgroup_root *root); 213 struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline); 214 void cgroup_kn_unlock(struct kernfs_node *kn); 215 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen, 216 struct cgroup_namespace *ns); 217 218 void cgroup_free_root(struct cgroup_root *root); 219 void init_cgroup_root(struct cgroup_fs_context *ctx); 220 int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask); 221 int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask); 222 int cgroup_do_get_tree(struct fs_context *fc); 223 224 int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp); 225 void cgroup_migrate_finish(struct cgroup_mgctx *mgctx); 226 void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp, 227 struct cgroup_mgctx *mgctx); 228 int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx); 229 int cgroup_migrate(struct task_struct *leader, bool threadgroup, 230 struct cgroup_mgctx *mgctx); 231 232 int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, 233 bool threadgroup); 234 struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup) 235 __acquires(&cgroup_threadgroup_rwsem); 236 void cgroup_procs_write_finish(struct task_struct *task) 237 __releases(&cgroup_threadgroup_rwsem); 238 239 void cgroup_lock_and_drain_offline(struct cgroup *cgrp); 240 241 int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode); 242 int cgroup_rmdir(struct kernfs_node *kn); 243 int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, 244 struct kernfs_root *kf_root); 245 246 int __cgroup_task_count(const struct cgroup *cgrp); 247 int cgroup_task_count(const struct cgroup *cgrp); 248 249 /* 250 * rstat.c 251 */ 252 int cgroup_rstat_init(struct cgroup *cgrp); 253 void cgroup_rstat_exit(struct cgroup *cgrp); 254 void cgroup_rstat_boot(void); 255 void cgroup_base_stat_cputime_show(struct seq_file *seq); 256 257 /* 258 * namespace.c 259 */ 260 extern const struct proc_ns_operations cgroupns_operations; 261 262 /* 263 * cgroup-v1.c 264 */ 265 extern struct cftype cgroup1_base_files[]; 266 extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops; 267 extern const struct fs_parameter_description cgroup1_fs_parameters; 268 269 int proc_cgroupstats_show(struct seq_file *m, void *v); 270 bool cgroup1_ssid_disabled(int ssid); 271 void cgroup1_pidlist_destroy_all(struct cgroup *cgrp); 272 void cgroup1_release_agent(struct work_struct *work); 273 void cgroup1_check_for_release(struct cgroup *cgrp); 274 int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param); 275 int cgroup1_get_tree(struct fs_context *fc); 276 int cgroup1_reconfigure(struct fs_context *ctx); 277 278 #endif /* __CGROUP_INTERNAL_H */ 279