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authorTejun Heo <tj@kernel.org>2013-08-26 18:40:56 -0400
committerTejun Heo <tj@kernel.org>2013-08-26 18:40:56 -0400
commit35cf083619da5677f83e9a8eae813f0b413d7082 (patch)
tree509ea1ae09644bc82040ec919fa94c928e98db27 /kernel/cgroup.c
parent6e6eab0efdf48fb2d8d7aee904d7740acb4661c6 (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.c26
1 files changed, 10 insertions, 16 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index ef43e3f453ef..921b1387c944 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);
}
/**