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-rw-r--r--include/linux/cgroup-defs.h26
-rw-r--r--include/linux/cgroup.h13
2 files changed, 37 insertions, 2 deletions
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 10d814bcd487..df589a097539 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -84,6 +84,17 @@ enum {
};
/*
+ * cgroup_file is the handle for a file instance created in a cgroup which
+ * is used, for example, to generate file changed notifications. This can
+ * be obtained by setting cftype->file_offset.
+ */
+struct cgroup_file {
+ /* do not access any fields from outside cgroup core */
+ struct list_head node; /* anchored at css->files */
+ struct kernfs_node *kn;
+};
+
+/*
* Per-subsystem/per-cgroup state maintained by the system. This is the
* fundamental structural building block that controllers deal with.
*
@@ -123,6 +134,9 @@ struct cgroup_subsys_state {
*/
u64 serial_nr;
+ /* all cgroup_files associated with this css */
+ struct list_head files;
+
/* percpu_ref killing and RCU release */
struct rcu_head rcu_head;
struct work_struct destroy_work;
@@ -226,8 +240,8 @@ struct cgroup {
int populated_cnt;
struct kernfs_node *kn; /* cgroup kernfs entry */
- struct kernfs_node *procs_kn; /* kn for "cgroup.procs" */
- struct kernfs_node *events_kn; /* kn for "cgroup.events" */
+ struct cgroup_file procs_file; /* handle for "cgroup.procs" */
+ struct cgroup_file events_file; /* handle for "cgroup.events" */
/*
* The bitmask of subsystems enabled on the child cgroups.
@@ -336,6 +350,14 @@ struct cftype {
unsigned int flags;
/*
+ * If non-zero, should contain the offset from the start of css to
+ * a struct cgroup_file field. cgroup will record the handle of
+ * the created file into it. The recorded handle can be used as
+ * long as the containing css remains accessible.
+ */
+ unsigned int file_offset;
+
+ /*
* Fields used for internal bookkeeping. Initialized automatically
* during registration.
*/
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 355bf2ed8867..fb717f2cba5b 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -490,6 +490,19 @@ static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
pr_cont_kernfs_path(cgrp->kn);
}
+/**
+ * cgroup_file_notify - generate a file modified event for a cgroup_file
+ * @cfile: target cgroup_file
+ *
+ * @cfile must have been obtained by setting cftype->file_offset.
+ */
+static inline void cgroup_file_notify(struct cgroup_file *cfile)
+{
+ /* might not have been created due to one of the CFTYPE selector flags */
+ if (cfile->kn)
+ kernfs_notify(cfile->kn);
+}
+
#else /* !CONFIG_CGROUPS */
struct cgroup_subsys_state;