From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin KaFai Lau Subject: [PATCH -next 1/4] cgroup: Add cgroup_get_from_fd Date: Tue, 21 Jun 2016 17:23:19 -0700 Message-ID: <1466555002-1316296-2-git-send-email-kafai@fb.com> References: <1466555002-1316296-1-git-send-email-kafai@fb.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Alexei Starovoitov , Daniel Borkmann , Tejun Heo , To: , , Return-path: In-Reply-To: <1466555002-1316296-1-git-send-email-kafai-b10kYP2dOMg@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org Add a helper function to get a cgroup2 from a fd. It will be stored in a bpf array (BPF_MAP_TYPE_CGROUP_ARRAY) which will be introduced in the later patch. Signed-off-by: Martin KaFai Lau Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Tejun Heo --- include/linux/cgroup.h | 1 + kernel/cgroup.c | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index a20320c..984f73b 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -87,6 +87,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, struct cgroup_subsys *ss); struct cgroup *cgroup_get_from_path(const char *path); +struct cgroup *cgroup_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.c b/kernel/cgroup.c index 86cb5c6..616c751 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -62,6 +62,7 @@ #include #include #include +#include #include /* @@ -6205,6 +6206,31 @@ struct cgroup *cgroup_get_from_path(const char *path) } 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; + + f = fget_raw(fd); + if (!f) + return NULL; + + css = css_tryget_online_from_dir(f->f_path.dentry, NULL); + fput(f); + if (IS_ERR(css)) + return ERR_CAST(css); + + cgrp = css->cgroup; + if (!cgroup_on_dfl(cgrp)) { + cgroup_put(cgrp); + return ERR_PTR(-EINVAL); + } + + return cgrp; +} +EXPORT_SYMBOL_GPL(cgroup_get_from_fd); + /* * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data * definition in cgroup-defs.h. -- 2.5.1