Revert "cgroup: enable cgroup_get_from_file() on cgroup1"

This reverts commit f3a2aebdd6fb90e444d595e46de64e822af419da.

The commit enabled looking up v1 cgroups via cgroup_get_from_file().
However, there are multiple users, including CLONE_INTO_CGROUP, which have
been assuming that it would only look up v2 cgroups. Returning v1 cgroups
breaks them.

Let's revert the commit and retry later with a separate lookup interface
which allows both v1 and v2.

Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/000000000000385cbf05ea3f1862@google.com
Cc: Yosry Ahmed <yosryahmed@google.com>

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index ecf409e..6d8a5a4 100644 (file)
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -6234,6 +6234,11 @@ static struct cgroup *cgroup_get_from_file(struct file *f)
                return ERR_CAST(css);
 
        cgrp = css->cgroup;
+       if (!cgroup_on_dfl(cgrp)) {
+               cgroup_put(cgrp);
+               return ERR_PTR(-EBADF);
+       }
+
        return cgrp;
 }