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