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authorDavid S. Miller <davem@davemloft.net>2015-12-08 22:01:38 -0500
committerDavid S. Miller <davem@davemloft.net>2015-12-08 22:01:38 -0500
commitbc9b145a092aca91a7f6ef40cdb3628b6ada7ec9 (patch)
tree60407a8c19e907a91c736fb95f1a30186a7542d5
parentRevert "Merge branch 'vsock-virtio'" (diff)
parentcgroup: implement cgroup_get_from_path() and expose cgroup_put() (diff)
downloadlinux-dev-bc9b145a092aca91a7f6ef40cdb3628b6ada7ec9.tar.xz
linux-dev-bc9b145a092aca91a7f6ef40cdb3628b6ada7ec9.zip
Merge branch 'for-4.5-ancestor-test' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Preparatory changes for some new socket cgroup infrastructure and netfilter targets. Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--fs/kernfs/dir.c46
-rw-r--r--include/linux/cgroup-defs.h14
-rw-r--r--include/linux/cgroup.h25
-rw-r--r--include/linux/kernfs.h12
-rw-r--r--kernel/cgroup.c71
5 files changed, 140 insertions, 28 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 91e004518237..742bf4a230e8 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -694,6 +694,29 @@ static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
return NULL;
}
+static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent,
+ const unsigned char *path,
+ const void *ns)
+{
+ static char path_buf[PATH_MAX]; /* protected by kernfs_mutex */
+ size_t len = strlcpy(path_buf, path, PATH_MAX);
+ char *p = path_buf;
+ char *name;
+
+ lockdep_assert_held(&kernfs_mutex);
+
+ if (len >= PATH_MAX)
+ return NULL;
+
+ while ((name = strsep(&p, "/")) && parent) {
+ if (*name == '\0')
+ continue;
+ parent = kernfs_find_ns(parent, name, ns);
+ }
+
+ return parent;
+}
+
/**
* kernfs_find_and_get_ns - find and get kernfs_node with the given name
* @parent: kernfs_node to search under
@@ -719,6 +742,29 @@ struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
/**
+ * kernfs_walk_and_get_ns - find and get kernfs_node with the given path
+ * @parent: kernfs_node to search under
+ * @path: path to look for
+ * @ns: the namespace tag to use
+ *
+ * Look for kernfs_node with path @path under @parent and get a reference
+ * if found. This function may sleep and returns pointer to the found
+ * kernfs_node on success, %NULL on failure.
+ */
+struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent,
+ const char *path, const void *ns)
+{
+ struct kernfs_node *kn;
+
+ mutex_lock(&kernfs_mutex);
+ kn = kernfs_walk_ns(parent, path, ns);
+ kernfs_get(kn);
+ mutex_unlock(&kernfs_mutex);
+
+ return kn;
+}
+
+/**
* kernfs_create_root - create a new kernfs hierarchy
* @scops: optional syscall operations for the hierarchy
* @flags: KERNFS_ROOT_* flags
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 60d44b26276d..504d8591b6d3 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -235,6 +235,14 @@ struct cgroup {
int id;
/*
+ * The depth this cgroup is at. The root is at depth zero and each
+ * step down the hierarchy increments the level. This along with
+ * ancestor_ids[] can determine whether a given cgroup is a
+ * descendant of another without traversing the hierarchy.
+ */
+ int level;
+
+ /*
* Each non-empty css_set associated with this cgroup contributes
* one to populated_cnt. All children with non-zero popuplated_cnt
* of their own contribute one. The count is zero iff there's no
@@ -289,6 +297,9 @@ struct cgroup {
/* used to schedule release agent */
struct work_struct release_agent_work;
+
+ /* ids of the ancestors at each level including self */
+ int ancestor_ids[];
};
/*
@@ -308,6 +319,9 @@ struct cgroup_root {
/* The root cgroup. Root is destroyed on its release. */
struct cgroup cgrp;
+ /* for cgrp->ancestor_ids[0] */
+ int cgrp_ancestor_id_storage;
+
/* Number of cgroups in the hierarchy, used only for /proc/cgroups */
atomic_t nr_cgrps;
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 22e3754f89c5..4c3ffab81ba7 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -81,7 +81,8 @@ struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup,
struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
struct cgroup_subsys *ss);
-bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor);
+struct cgroup *cgroup_get_from_path(const char *path);
+
int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
@@ -352,6 +353,11 @@ static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n)
percpu_ref_put_many(&css->refcnt, n);
}
+static inline void cgroup_put(struct cgroup *cgrp)
+{
+ css_put(&cgrp->self);
+}
+
/**
* task_css_set_check - obtain a task's css_set with extra access conditions
* @task: the task to obtain css_set for
@@ -459,6 +465,23 @@ static inline struct cgroup *task_cgroup(struct task_struct *task,
return task_css(task, subsys_id)->cgroup;
}
+/**
+ * cgroup_is_descendant - test ancestry
+ * @cgrp: the cgroup to be tested
+ * @ancestor: possible ancestor of @cgrp
+ *
+ * Test whether @cgrp is a descendant of @ancestor. It also returns %true
+ * if @cgrp == @ancestor. This function is safe to call as long as @cgrp
+ * and @ancestor are accessible.
+ */
+static inline bool cgroup_is_descendant(struct cgroup *cgrp,
+ struct cgroup *ancestor)
+{
+ if (cgrp->root != ancestor->root || cgrp->level < ancestor->level)
+ return false;
+ return cgrp->ancestor_ids[ancestor->level] == ancestor->id;
+}
+
/* no synchronization, the result can only be used as a hint */
static inline bool cgroup_is_populated(struct cgroup *cgrp)
{
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 5d4e9c4b821d..af51df35d749 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -274,6 +274,8 @@ void pr_cont_kernfs_path(struct kernfs_node *kn);
struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn);
struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
const char *name, const void *ns);
+struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent,
+ const char *path, const void *ns);
void kernfs_get(struct kernfs_node *kn);
void kernfs_put(struct kernfs_node *kn);
@@ -350,6 +352,10 @@ static inline struct kernfs_node *
kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name,
const void *ns)
{ return NULL; }
+static inline struct kernfs_node *
+kernfs_walk_and_get_ns(struct kernfs_node *parent, const char *path,
+ const void *ns)
+{ return NULL; }
static inline void kernfs_get(struct kernfs_node *kn) { }
static inline void kernfs_put(struct kernfs_node *kn) { }
@@ -431,6 +437,12 @@ kernfs_find_and_get(struct kernfs_node *kn, const char *name)
}
static inline struct kernfs_node *
+kernfs_walk_and_get(struct kernfs_node *kn, const char *path)
+{
+ return kernfs_walk_and_get_ns(kn, path, NULL);
+}
+
+static inline struct kernfs_node *
kernfs_create_dir(struct kernfs_node *parent, const char *name, umode_t mode,
void *priv)
{
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index f1603c153890..3db5e8f5b702 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -434,11 +434,6 @@ static bool cgroup_tryget(struct cgroup *cgrp)
return css_tryget(&cgrp->self);
}
-static void cgroup_put(struct cgroup *cgrp)
-{
- css_put(&cgrp->self);
-}
-
struct cgroup_subsys_state *of_css(struct kernfs_open_file *of)
{
struct cgroup *cgrp = of->kn->parent->priv;
@@ -459,25 +454,6 @@ struct cgroup_subsys_state *of_css(struct kernfs_open_file *of)
}
EXPORT_SYMBOL_GPL(of_css);
-/**
- * cgroup_is_descendant - test ancestry
- * @cgrp: the cgroup to be tested
- * @ancestor: possible ancestor of @cgrp
- *
- * Test whether @cgrp is a descendant of @ancestor. It also returns %true
- * if @cgrp == @ancestor. This function is safe to call as long as @cgrp
- * and @ancestor are accessible.
- */
-bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor)
-{
- while (cgrp) {
- if (cgrp == ancestor)
- return true;
- cgrp = cgroup_parent(cgrp);
- }
- return false;
-}
-
static int notify_on_release(const struct cgroup *cgrp)
{
return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
@@ -1903,6 +1879,7 @@ static int cgroup_setup_root(struct cgroup_root *root, unsigned long ss_mask)
if (ret < 0)
goto out;
root_cgrp->id = ret;
+ root_cgrp->ancestor_ids[0] = ret;
ret = percpu_ref_init(&root_cgrp->self.refcnt, css_release, 0,
GFP_KERNEL);
@@ -4846,11 +4823,11 @@ err_free_css:
static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
umode_t mode)
{
- struct cgroup *parent, *cgrp;
+ struct cgroup *parent, *cgrp, *tcgrp;
struct cgroup_root *root;
struct cgroup_subsys *ss;
struct kernfs_node *kn;
- int ssid, ret;
+ int level, ssid, ret;
/* Do not accept '\n' to prevent making /proc/<pid>/cgroup unparsable.
*/
@@ -4861,9 +4838,11 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
if (!parent)
return -ENODEV;
root = parent->root;
+ level = parent->level + 1;
/* allocate the cgroup and its ID, 0 is reserved for the root */
- cgrp = kzalloc(sizeof(*cgrp), GFP_KERNEL);
+ cgrp = kzalloc(sizeof(*cgrp) +
+ sizeof(cgrp->ancestor_ids[0]) * (level + 1), GFP_KERNEL);
if (!cgrp) {
ret = -ENOMEM;
goto out_unlock;
@@ -4887,6 +4866,10 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
cgrp->self.parent = &parent->self;
cgrp->root = root;
+ cgrp->level = level;
+
+ for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp))
+ cgrp->ancestor_ids[tcgrp->level] = tcgrp->id;
if (notify_on_release(parent))
set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
@@ -5765,6 +5748,40 @@ struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
return id > 0 ? idr_find(&ss->css_idr, id) : NULL;
}
+/**
+ * cgroup_get_from_path - lookup and get a cgroup from its default hierarchy path
+ * @path: path on the default hierarchy
+ *
+ * Find the cgroup at @path on the default hierarchy, increment its
+ * reference count and return it. Returns pointer to the found cgroup on
+ * success, ERR_PTR(-ENOENT) if @path doens't exist and ERR_PTR(-ENOTDIR)
+ * if @path points to a non-directory.
+ */
+struct cgroup *cgroup_get_from_path(const char *path)
+{
+ struct kernfs_node *kn;
+ struct cgroup *cgrp;
+
+ mutex_lock(&cgroup_mutex);
+
+ kn = kernfs_walk_and_get(cgrp_dfl_root.cgrp.kn, path);
+ if (kn) {
+ if (kernfs_type(kn) == KERNFS_DIR) {
+ cgrp = kn->priv;
+ cgroup_get(cgrp);
+ } else {
+ cgrp = ERR_PTR(-ENOTDIR);
+ }
+ kernfs_put(kn);
+ } else {
+ cgrp = ERR_PTR(-ENOENT);
+ }
+
+ mutex_unlock(&cgroup_mutex);
+ return cgrp;
+}
+EXPORT_SYMBOL_GPL(cgroup_get_from_path);
+
#ifdef CONFIG_CGROUP_DEBUG
static struct cgroup_subsys_state *
debug_css_alloc(struct cgroup_subsys_state *parent_css)