}
/**
- * kernfs_deref_open_node - Get kernfs_open_node corresponding to @kn.
- *
- * @of: associated kernfs_open_file instance.
- * @kn: target kernfs_node.
- *
- * Fetch and return ->attr.open of @kn if @of->list is non empty.
- * If @of->list is not empty we can safely assume that @of is on
- * @kn->attr.open->files list and this guarantees that @kn->attr.open
- * will not vanish i.e. dereferencing outside RCU read-side critical
- * section is safe here.
- *
- * The caller needs to make sure that @of->list is not empty.
+ * of_on - Return the kernfs_open_node of the specified kernfs_open_file
+ * @of: taret kernfs_open_file
*/
-static struct kernfs_open_node *
-kernfs_deref_open_node(struct kernfs_open_file *of, struct kernfs_node *kn)
+static struct kernfs_open_node *of_on(struct kernfs_open_file *of)
{
- struct kernfs_open_node *on;
-
- on = rcu_dereference_check(kn->attr.open, !list_empty(&of->list));
-
- return on;
+ return rcu_dereference_protected(of->kn->attr.open,
+ !list_empty(&of->list));
}
/**
- * kernfs_deref_open_node_protected - Get kernfs_open_node corresponding to @kn
+ * kernfs_deref_open_node_locked - Get kernfs_open_node corresponding to @kn
*
* @kn: target kernfs_node.
*
* The caller needs to make sure that kernfs_open_file_mutex is held.
*/
static struct kernfs_open_node *
-kernfs_deref_open_node_protected(struct kernfs_node *kn)
+kernfs_deref_open_node_locked(struct kernfs_node *kn)
{
return rcu_dereference_protected(kn->attr.open,
lockdep_is_held(kernfs_open_file_mutex_ptr(kn)));
static int kernfs_seq_show(struct seq_file *sf, void *v)
{
struct kernfs_open_file *of = sf->private;
- struct kernfs_open_node *on = kernfs_deref_open_node(of, of->kn);
-
- if (!on)
- return -EINVAL;
- of->event = atomic_read(&on->event);
+ of->event = atomic_read(&of_on(of)->event);
return of->kn->attr.ops->seq_show(sf, v);
}
struct kernfs_open_file *of = kernfs_of(iocb->ki_filp);
ssize_t len = min_t(size_t, iov_iter_count(iter), PAGE_SIZE);
const struct kernfs_ops *ops;
- struct kernfs_open_node *on;
char *buf;
buf = of->prealloc_buf;
goto out_free;
}
- on = kernfs_deref_open_node(of, of->kn);
- if (!on) {
- len = -EINVAL;
- mutex_unlock(&of->mutex);
- goto out_free;
- }
-
- of->event = atomic_read(&on->event);
+ of->event = atomic_read(&of_on(of)->event);
ops = kernfs_ops(of->kn);
if (ops->read)
struct mutex *mutex = NULL;
mutex = kernfs_open_file_mutex_lock(kn);
- on = kernfs_deref_open_node_protected(kn);
+ on = kernfs_deref_open_node_locked(kn);
if (on) {
list_add_tail(&of->list, &on->files);
mutex = kernfs_open_file_mutex_lock(kn);
- on = kernfs_deref_open_node_protected(kn);
+ on = kernfs_deref_open_node_locked(kn);
if (!on) {
mutex_unlock(mutex);
return;
return;
mutex = kernfs_open_file_mutex_lock(kn);
- on = kernfs_deref_open_node_protected(kn);
+ on = kernfs_deref_open_node_locked(kn);
if (!on) {
mutex_unlock(mutex);
return;
*/
__poll_t kernfs_generic_poll(struct kernfs_open_file *of, poll_table *wait)
{
- struct kernfs_node *kn = kernfs_dentry_node(of->file->f_path.dentry);
- struct kernfs_open_node *on = kernfs_deref_open_node(of, kn);
-
- if (!on)
- return EPOLLERR;
+ struct kernfs_open_node *on = of_on(of);
poll_wait(of->file, &on->poll, wait);