diff options
| author | Tejun Heo <tj@kernel.org> | 2013-08-26 18:40:56 -0400 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-08-26 18:40:56 -0400 |
| commit | 35cf083619da5677f83e9a8eae813f0b413d7082 (patch) | |
| tree | 509ea1ae09644bc82040ec919fa94c928e98db27 /kernel/cgroup.c | |
| parent | 6e6eab0efdf48fb2d8d7aee904d7740acb4661c6 (diff) | |
cgroup: rename cgroup_css_from_dir() to css_from_dir() and update its syntax
cgroup_css_from_dir() will grow another user. In preparation, make
the following changes.
* All css functions are prefixed with just "css_", rename it to
css_from_dir().
* Take dentry * instead of file * as dentry is what ultimately
identifies a cgroup and file may not always be available. Note that
the function now checkes whether @dentry->d_inode is NULL as the
caller now may specify a negative dentry.
* Make it take cgroup_subsys * instead of integer subsys_id. This
simplifies the function and allows specifying no subsystem for
cgroup->dummy_css.
* Make return section a bit less verbose.
This patch doesn't introduce any behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 26 |
1 files changed, 10 insertions, 16 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index ef43e3f453e..921b1387c94 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -5700,34 +5700,28 @@ struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id) EXPORT_SYMBOL_GPL(css_lookup); /** - * cgroup_css_from_dir - get corresponding css from file open on cgroup dir - * @f: directory file of interest - * @id: subsystem id of interest + * css_from_dir - get corresponding css from the dentry of a cgroup dir + * @dentry: directory dentry of interest + * @ss: subsystem of interest * * Must be called under RCU read lock. The caller is responsible for * pinning the returned css if it needs to be accessed outside the RCU * critical section. */ -struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id) +struct cgroup_subsys_state *css_from_dir(struct dentry *dentry, + struct cgroup_subsys *ss) { struct cgroup *cgrp; - struct inode *inode; - struct cgroup_subsys_state *css; WARN_ON_ONCE(!rcu_read_lock_held()); - inode = file_inode(f); - /* check in cgroup filesystem dir */ - if (inode->i_op != &cgroup_dir_inode_operations) + /* is @dentry a cgroup dir? */ + if (!dentry->d_inode || + dentry->d_inode->i_op != &cgroup_dir_inode_operations) return ERR_PTR(-EBADF); - if (id < 0 || id >= CGROUP_SUBSYS_COUNT) - return ERR_PTR(-EINVAL); - - /* get cgroup */ - cgrp = __d_cgrp(f->f_dentry); - css = cgroup_css(cgrp, id); - return css ? css : ERR_PTR(-ENOENT); + cgrp = __d_cgrp(dentry); + return cgroup_css(cgrp, ss->subsys_id) ?: ERR_PTR(-ENOENT); } /** |