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authorYosry Ahmed <yosryahmed@google.com>2022-10-11 03:33:58 +0300
committerTejun Heo <tj@kernel.org>2022-10-11 19:50:03 +0300
commita6d1ce5951185ee91bbe6909fe2758f3625561b0 (patch)
tree450d6875a29897cf85154d2f4ca9dffc55753006
parent03db7716159477b595e9af01be8003b7e994cc79 (diff)
downloadlinux-a6d1ce5951185ee91bbe6909fe2758f3625561b0.tar.xz
cgroup: add cgroup_v1v2_get_from_[fd/file]()
Add cgroup_v1v2_get_from_fd() and cgroup_v1v2_get_from_file() that support both cgroup1 and cgroup2. Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
-rw-r--r--include/linux/cgroup.h1
-rw-r--r--kernel/cgroup/cgroup.c50
2 files changed, 45 insertions, 6 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 398f0bce7c21..a88de5bdeaa9 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -106,6 +106,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
struct cgroup *cgroup_get_from_path(const char *path);
struct cgroup *cgroup_get_from_fd(int fd);
+struct cgroup *cgroup_v1v2_get_from_fd(int fd);
int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 6d8a5a40c24d..6349a9fe9ec1 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -6224,16 +6224,36 @@ void cgroup_fork(struct task_struct *child)
INIT_LIST_HEAD(&child->cg_list);
}
-static struct cgroup *cgroup_get_from_file(struct file *f)
+/**
+ * cgroup_v1v2_get_from_file - get a cgroup pointer from a file pointer
+ * @f: file corresponding to cgroup_dir
+ *
+ * Find the cgroup from a file pointer associated with a cgroup directory.
+ * Returns a pointer to the cgroup on success. ERR_PTR is returned if the
+ * cgroup cannot be found.
+ */
+static struct cgroup *cgroup_v1v2_get_from_file(struct file *f)
{
struct cgroup_subsys_state *css;
- struct cgroup *cgrp;
css = css_tryget_online_from_dir(f->f_path.dentry, NULL);
if (IS_ERR(css))
return ERR_CAST(css);
- cgrp = css->cgroup;
+ return css->cgroup;
+}
+
+/**
+ * cgroup_get_from_file - same as cgroup_v1v2_get_from_file, but only supports
+ * cgroup2.
+ */
+static struct cgroup *cgroup_get_from_file(struct file *f)
+{
+ struct cgroup *cgrp = cgroup_v1v2_get_from_file(f);
+
+ if (IS_ERR(cgrp))
+ return ERR_CAST(cgrp);
+
if (!cgroup_on_dfl(cgrp)) {
cgroup_put(cgrp);
return ERR_PTR(-EBADF);
@@ -6734,14 +6754,14 @@ EXPORT_SYMBOL_GPL(cgroup_get_from_path);
/**
* cgroup_get_from_fd - get a cgroup pointer from a fd
- * @fd: fd obtained by open(cgroup2_dir)
+ * @fd: fd obtained by open(cgroup_dir)
*
* Find the cgroup from a fd which should be obtained
* by opening a cgroup directory. Returns a pointer to the
* cgroup on success. ERR_PTR is returned if the cgroup
* cannot be found.
*/
-struct cgroup *cgroup_get_from_fd(int fd)
+struct cgroup *cgroup_v1v2_get_from_fd(int fd)
{
struct cgroup *cgrp;
struct file *f;
@@ -6750,10 +6770,28 @@ struct cgroup *cgroup_get_from_fd(int fd)
if (!f)
return ERR_PTR(-EBADF);
- cgrp = cgroup_get_from_file(f);
+ cgrp = cgroup_v1v2_get_from_file(f);
fput(f);
return cgrp;
}
+
+/**
+ * cgroup_get_from_fd - same as cgroup_v1v2_get_from_fd, but only supports
+ * cgroup2.
+ */
+struct cgroup *cgroup_get_from_fd(int fd)
+{
+ struct cgroup *cgrp = cgroup_v1v2_get_from_fd(fd);
+
+ if (IS_ERR(cgrp))
+ return ERR_CAST(cgrp);
+
+ if (!cgroup_on_dfl(cgrp)) {
+ cgroup_put(cgrp);
+ return ERR_PTR(-EBADF);
+ }
+ return cgrp;
+}
EXPORT_SYMBOL_GPL(cgroup_get_from_fd);
static u64 power_of_ten(int power)