HID: uhid: avoid magic-numbers when setting strings

Avoid hard-coding the target buffer sizes and use sizeof() instead. This
also makes us future-proof to buffer-extensions later on.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/uhid.c

@@ -363,7 +363,7 @@ static int uhid_dev_create2(struct uhid_device *uhid,
 			    const struct uhid_event *ev)
 {
 	struct hid_device *hid;
-	size_t rd_size;
+	size_t rd_size, len;
 	void *rd_data;
 	int ret;
 
@@ -387,12 +387,12 @@ static int uhid_dev_create2(struct uhid_device *uhid,
 		goto err_free;
 	}
 
-	strncpy(hid->name, ev->u.create2.name, 127);
-	hid->name[127] = 0;
-	strncpy(hid->phys, ev->u.create2.phys, 63);
-	hid->phys[63] = 0;
-	strncpy(hid->uniq, ev->u.create2.uniq, 63);
-	hid->uniq[63] = 0;
+	len = min(sizeof(hid->name), sizeof(ev->u.create2.name)) - 1;
+	strncpy(hid->name, ev->u.create2.name, len);
+	len = min(sizeof(hid->phys), sizeof(ev->u.create2.phys)) - 1;
+	strncpy(hid->phys, ev->u.create2.phys, len);
+	len = min(sizeof(hid->uniq), sizeof(ev->u.create2.uniq)) - 1;
+	strncpy(hid->uniq, ev->u.create2.uniq, len);
 
 	hid->ll_driver = &uhid_hid_driver;
 	hid->bus = ev->u.create2.bus;