diff options
| author | Christian Brauner <christian.brauner@ubuntu.com> | 2020-02-05 14:26:21 +0100 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2020-02-12 17:57:51 -0500 |
| commit | f3553220d4cc458d69f7da6e71a3a6097778bd28 (patch) | |
| tree | 8b1323e0a992356c6999df4ea5fdc19e6850cedb /kernel/cgroup | |
| parent | 5a5cf5cb30d7815c01035fde4b84edef85d11c68 (diff) | |
cgroup: add cgroup_may_write() helper
Add a cgroup_may_write() helper which we can use in the
CLONE_INTO_CGROUP patch series to verify that we can write to the
destination cgroup.
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: cgroups@vger.kernel.org
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 | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 502769b2683c..6d8bdddd8c28 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4654,13 +4654,28 @@ static int cgroup_procs_show(struct seq_file *s, void *v) return 0; } +static int cgroup_may_write(const struct cgroup *cgrp, struct super_block *sb) +{ + int ret; + struct inode *inode; + + lockdep_assert_held(&cgroup_mutex); + + inode = kernfs_get_inode(sb, cgrp->procs_file.kn); + if (!inode) + return -ENOMEM; + + ret = inode_permission(inode, MAY_WRITE); + iput(inode); + return ret; +} + static int cgroup_procs_write_permission(struct cgroup *src_cgrp, struct cgroup *dst_cgrp, struct super_block *sb) { struct cgroup_namespace *ns = current->nsproxy->cgroup_ns; struct cgroup *com_cgrp = src_cgrp; - struct inode *inode; int ret; lockdep_assert_held(&cgroup_mutex); @@ -4670,12 +4685,7 @@ static int cgroup_procs_write_permission(struct cgroup *src_cgrp, com_cgrp = cgroup_parent(com_cgrp); /* %current should be authorized to migrate to the common ancestor */ - inode = kernfs_get_inode(sb, com_cgrp->procs_file.kn); - if (!inode) - return -ENOMEM; - - ret = inode_permission(inode, MAY_WRITE); - iput(inode); + ret = cgroup_may_write(com_cgrp, sb); if (ret) return ret; |