/**
* kernfs_put - put a reference count on a kernfs_node
* @kn: the target kernfs_node
*
* Put a reference count of @kn and destroy it if it reached zero.
*/
void kernfs_put(struct kernfs_node *kn)
{
struct kernfs_node *parent;
struct kernfs_root *root;
if (!kn || !atomic_dec_and_test(&kn->count))
return;
root = kernfs_root(kn);
repeat:
/*
* Moving/renaming is always done while holding reference.
* kn->parent won't change beneath us.
*/
parent = kn->parent;
WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS,
"kernfs_put: %s/%s: released with incorrect active_ref %d\n",
parent ? parent->name : "", kn->name, atomic_read(&kn->active));
if (kernfs_type(kn) == KERNFS_LINK)
kernfs_put(kn->symlink.target_kn);
kfree_const(kn->name);
if (kn->iattr) {
if (kn->iattr->ia_secdata)
security_release_secctx(kn->iattr->ia_secdata,
kn->iattr->ia_secdata_len);
simple_xattrs_free(&kn->iattr->xattrs);
}
kfree(kn->iattr);
ida_simple_remove(&root->ino_ida, kn->ino);
kmem_cache_free(kernfs_node_cache, kn);
kn = parent;
if (kn) {
if (atomic_dec_and_test(&kn->count))
goto repeat;
} else {
/* just released the root kn, free @root too */
ida_destroy(&root->ino_ida);
kfree(root);
}
}
/*! 2017. 3.18 study -ing */
void kernfs_put(struct kernfs_node *kn)
{
struct kernfs_node *parent;
struct kernfs_root *root;
if (!kn || !atomic_dec_and_test(&kn->count))
return;
root = kernfs_root(kn);
repeat:
/* Moving/renaming is always done while holding reference.
* kn->parent won't change beneath us.
*/
parent = kn->parent;
WARN(!(kn->flags & KERNFS_REMOVED), "kernfs: free using entry: %s/%s\n",
parent ? parent->name : "", kn->name);
if (kernfs_type(kn) == KERNFS_LINK)
kernfs_put(kn->symlink.target_kn);
if (!(kn->flags & KERNFS_STATIC_NAME))
kfree(kn->name);
if (kn->iattr) {
if (kn->iattr->ia_secdata)
/*! Do Nothing */
security_release_secctx(kn->iattr->ia_secdata,
kn->iattr->ia_secdata_len);
simple_xattrs_free(&kn->iattr->xattrs);
}
kfree(kn->iattr);
ida_simple_remove(&root->ino_ida, kn->ino);
kmem_cache_free(kernfs_node_cache, kn);
kn = parent;
if (kn) {
if (atomic_dec_and_test(&kn->count))
goto repeat;
} else {
/* just released the root kn, free @root too */
ida_destroy(&root->ino_ida);
kfree(root);
}
}
