| Message ID | 1466555002-1316296-2-git-send-email-kafai@fb.com |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
Hello, Martin. On Tue, Jun 21, 2016 at 05:23:19PM -0700, Martin KaFai Lau wrote: > @@ -6205,6 +6206,31 @@ struct cgroup *cgroup_get_from_path(const char *path) > } > EXPORT_SYMBOL_GPL(cgroup_get_from_path); Proper function comment would be nice. > +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; It returns NULL here. > + 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); But an ERR_PTR value here. Is this intentional? Also, wouldn't it make more sense to return -EBADF here, given that that's what css_tryget_online_from_dir() would return if the filesystem type is wrong? Thanks!
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 <linux/proc_ns.h> #include <linux/nsproxy.h> #include <linux/proc_ns.h> +#include <linux/file.h> #include <net/sock.h> /* @@ -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.
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 <kafai@fb.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Tejun Heo <tj@kernel.org> --- include/linux/cgroup.h | 1 + kernel/cgroup.c | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+)