+ /*
+ * Initially we receive a position value that corresponds to
+ * one more than the last pid shown (or 0 on the first call or
+ * after a seek to the start). Use a binary-search to find the
+ * next pid to display, if any
+ */
+ struct cgroup *cgrp = s->private;
+ int index = 0, pid = *pos;
+ int *iter;
+
+ down_read(&cgrp->pids_mutex);
+ if (pid) {
+ int end = cgrp->pids_length;
+
+ while (index < end) {
+ int mid = (index + end) / 2;
+ if (cgrp->tasks_pids[mid] == pid) {
+ index = mid;
+ break;
+ } else if (cgrp->tasks_pids[mid] <= pid)
+ index = mid + 1;
+ else
+ end = mid;
+ }
+ }
+ /* If we're off the end of the array, we're done */
+ if (index >= cgrp->pids_length)
+ return NULL;
+ /* Update the abstract position to be the actual pid that we found */
+ iter = cgrp->tasks_pids + index;
+ *pos = *iter;
+ return iter;
+}
+
+static void cgroup_tasks_stop(struct seq_file *s, void *v)
+{
+ struct cgroup *cgrp = s->private;
+ up_read(&cgrp->pids_mutex);
+}
+
+static void *cgroup_tasks_next(struct seq_file *s, void *v, loff_t *pos)
+{
+ struct cgroup *cgrp = s->private;
+ int *p = v;
+ int *end = cgrp->tasks_pids + cgrp->pids_length;
+
+ /*
+ * Advance to the next pid in the array. If this goes off the
+ * end, we're done
+ */
+ p++;
+ if (p >= end) {
+ return NULL;
+ } else {
+ *pos = *p;
+ return p;
+ }
+}
+
+static int cgroup_tasks_show(struct seq_file *s, void *v)
+{
+ return seq_printf(s, "%d\n", *(int *)v);
+}
+
+static struct seq_operations cgroup_tasks_seq_operations = {
+ .start = cgroup_tasks_start,
+ .stop = cgroup_tasks_stop,
+ .next = cgroup_tasks_next,
+ .show = cgroup_tasks_show,
+};
+
+static void release_cgroup_pid_array(struct cgroup *cgrp)
+{
+ down_write(&cgrp->pids_mutex);
+ BUG_ON(!cgrp->pids_use_count);
+ if (!--cgrp->pids_use_count) {
+ kfree(cgrp->tasks_pids);
+ cgrp->tasks_pids = NULL;
+ cgrp->pids_length = 0;
+ }
+ up_write(&cgrp->pids_mutex);
+}
+
+static int cgroup_tasks_release(struct inode *inode, struct file *file)
+{
+ struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);