/*! 2016-06-04 study -ing */
static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
const unsigned char *name,
const void *ns)
{
struct rb_node *node = parent->dir.children.rb_node;
bool has_ns = kernfs_ns_enabled(parent);
unsigned int hash;
lockdep_assert_held(&kernfs_mutex);
if (has_ns != (bool)ns) {
WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
has_ns ? "required" : "invalid", parent->name, name);
return NULL;
}
/*! name + ns 로 31bit hash 생성하여 return */
hash = kernfs_name_hash(name, ns);
/*! hash 비교해 가면서 원하는 kn을 찾는다. */
while (node) {
struct kernfs_node *kn;
int result;
kn = rb_to_kn(node);
/*! hash 와 kn->hash 비교 */
result = kernfs_name_compare(hash, name, ns, kn);
if (result < 0)
node = node->rb_left;
else if (result > 0)
node = node->rb_right;
else
return kn;
}
return NULL;
}
static int kernfs_sd_compare(const struct kernfs_node *left,
const struct kernfs_node *right)
{
return kernfs_name_compare(left->hash, left->name, left->ns, right);
}
