v4.19.13 snapshot.
diff --git a/fs/proc/devices.c b/fs/proc/devices.c
new file mode 100644
index 0000000..37d38697
--- /dev/null
+++ b/fs/proc/devices.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+static int devinfo_show(struct seq_file *f, void *v)
+{
+ int i = *(loff_t *) v;
+
+ if (i < CHRDEV_MAJOR_MAX) {
+ if (i == 0)
+ seq_puts(f, "Character devices:\n");
+ chrdev_show(f, i);
+ }
+#ifdef CONFIG_BLOCK
+ else {
+ i -= CHRDEV_MAJOR_MAX;
+ if (i == 0)
+ seq_puts(f, "\nBlock devices:\n");
+ blkdev_show(f, i);
+ }
+#endif
+ return 0;
+}
+
+static void *devinfo_start(struct seq_file *f, loff_t *pos)
+{
+ if (*pos < (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
+ return pos;
+ return NULL;
+}
+
+static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
+{
+ (*pos)++;
+ if (*pos >= (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
+ return NULL;
+ return pos;
+}
+
+static void devinfo_stop(struct seq_file *f, void *v)
+{
+ /* Nothing to do */
+}
+
+static const struct seq_operations devinfo_ops = {
+ .start = devinfo_start,
+ .next = devinfo_next,
+ .stop = devinfo_stop,
+ .show = devinfo_show
+};
+
+static int __init proc_devices_init(void)
+{
+ proc_create_seq("devices", 0, NULL, &devinfo_ops);
+ return 0;
+}
+fs_initcall(proc_devices_init);