1 files changed, 69 insertions, 2 deletions

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 327f37c9fdfa..1140357d46f4 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -3550,7 +3550,65 @@ static int cgroup_cpu_pressure_show(struct seq_file *seq, void *v)
 {
 	return psi_show(seq, &seq_css(seq)->cgroup->psi, PSI_CPU);
 }
-#endif
+
+static ssize_t cgroup_pressure_write(struct kernfs_open_file *of, char *buf,
+					  size_t nbytes, enum psi_res res)
+{
+	struct psi_trigger *new;
+	struct cgroup *cgrp;
+
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENODEV;
+
+	cgroup_get(cgrp);
+	cgroup_kn_unlock(of->kn);
+
+	new = psi_trigger_create(&cgrp->psi, buf, nbytes, res);
+	if (IS_ERR(new)) {
+		cgroup_put(cgrp);
+		return PTR_ERR(new);
+	}
+
+	psi_trigger_replace(&of->priv, new);
+
+	cgroup_put(cgrp);
+
+	return nbytes;
+}
+
+static ssize_t cgroup_io_pressure_write(struct kernfs_open_file *of,
+					  char *buf, size_t nbytes,
+					  loff_t off)
+{
+	return cgroup_pressure_write(of, buf, nbytes, PSI_IO);
+}
+
+static ssize_t cgroup_memory_pressure_write(struct kernfs_open_file *of,
+					  char *buf, size_t nbytes,
+					  loff_t off)
+{
+	return cgroup_pressure_write(of, buf, nbytes, PSI_MEM);
+}
+
+static ssize_t cgroup_cpu_pressure_write(struct kernfs_open_file *of,
+					  char *buf, size_t nbytes,
+					  loff_t off)
+{
+	return cgroup_pressure_write(of, buf, nbytes, PSI_CPU);
+}
+
+static __poll_t cgroup_pressure_poll(struct kernfs_open_file *of,
+					  poll_table *pt)
+{
+	return psi_trigger_poll(&of->priv, of->file, pt);
+}
+
+static void cgroup_pressure_release(struct kernfs_open_file *of)
+{
+	psi_trigger_replace(&of->priv, NULL);
+}
+#endif /* CONFIG_PSI */
 
 static int cgroup_freeze_show(struct seq_file *seq, void *v)
 {
@@ -4745,18 +4803,27 @@ static struct cftype cgroup_base_files[] = {
 		.name = "io.pressure",
 		.flags = CFTYPE_NOT_ON_ROOT,
 		.seq_show = cgroup_io_pressure_show,
+		.write = cgroup_io_pressure_write,
+		.poll = cgroup_pressure_poll,
+		.release = cgroup_pressure_release,
 	},
 	{
 		.name = "memory.pressure",
 		.flags = CFTYPE_NOT_ON_ROOT,
 		.seq_show = cgroup_memory_pressure_show,
+		.write = cgroup_memory_pressure_write,
+		.poll = cgroup_pressure_poll,
+		.release = cgroup_pressure_release,
 	},
 	{
 		.name = "cpu.pressure",
 		.flags = CFTYPE_NOT_ON_ROOT,
 		.seq_show = cgroup_cpu_pressure_show,
+		.write = cgroup_cpu_pressure_write,
+		.poll = cgroup_pressure_poll,
+		.release = cgroup_pressure_release,
 	},
-#endif
+#endif /* CONFIG_PSI */
 	{ }	/* terminate */
 };