diff options
| author | Christian Brauner <christian.brauner@ubuntu.com> | 2020-02-05 14:26:19 +0100 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2020-02-12 17:57:51 -0500 |
| commit | 17703097f3456498e6424614571648c6452f4d34 (patch) | |
| tree | f302a8825f3e6bc554d92a19b6e89c49b00cd2ed /kernel/cgroup | |
| parent | 6df970e4f5d2c273554550d40d8b92cea9bec1a0 (diff) | |
cgroup: add cgroup_get_from_file() helper
Add a helper cgroup_get_from_file(). The helper will be used in
subsequent patches to retrieve a cgroup while holding a reference to the
struct file it was taken from.
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: cgroups@vger.kernel.org
Acked-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup')
| -rw-r--r-- | kernel/cgroup/cgroup.c | 30 |
1 files changed, 19 insertions, 11 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 9ca51bf3769a..16fe1c6cad35 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -5880,6 +5880,24 @@ void cgroup_fork(struct task_struct *child) INIT_LIST_HEAD(&child->cg_list); } +static struct cgroup *cgroup_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; + if (!cgroup_on_dfl(cgrp)) { + cgroup_put(cgrp); + return ERR_PTR(-EBADF); + } + + return cgrp; +} + /** * cgroup_can_fork - called on a new task before the process is exposed * @child: the task in question. @@ -6171,7 +6189,6 @@ EXPORT_SYMBOL_GPL(cgroup_get_from_path); */ struct cgroup *cgroup_get_from_fd(int fd) { - struct cgroup_subsys_state *css; struct cgroup *cgrp; struct file *f; @@ -6179,17 +6196,8 @@ struct cgroup *cgroup_get_from_fd(int fd) if (!f) return ERR_PTR(-EBADF); - css = css_tryget_online_from_dir(f->f_path.dentry, NULL); + cgrp = cgroup_get_from_file(f); fput(f); - if (IS_ERR(css)) - return ERR_CAST(css); - - cgrp = css->cgroup; - if (!cgroup_on_dfl(cgrp)) { - cgroup_put(cgrp); - return ERR_PTR(-EBADF); - } - return cgrp; } EXPORT_SYMBOL_GPL(cgroup_get_from_fd); |