netdevsim: generate random switch id instead of using dev id

Current implementation of parent_id/switch_id does not follow the
original idea of being unique. The values are "0", "1", etc. Instead of
that, generate 32 random bytes.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/netdevsim/dev.c

@@ -17,6 +17,7 @@
 
 #include <linux/debugfs.h>
 #include <linux/device.h>
+#include <linux/random.h>
 #include <linux/rtnetlink.h>
 #include <net/devlink.h>
 
@@ -204,6 +205,8 @@ static struct nsim_dev *nsim_dev_create(struct nsim_bus_dev *nsim_bus_dev)
 		return ERR_PTR(-ENOMEM);
 	nsim_dev = devlink_priv(devlink);
 	nsim_dev->nsim_bus_dev = nsim_bus_dev;
+	nsim_dev->switch_id.id_len = sizeof(nsim_dev->switch_id.id);
+	get_random_bytes(nsim_dev->switch_id.id, nsim_dev->switch_id.id_len);
 
 	nsim_dev->fib_data = nsim_fib_create();
 	if (IS_ERR(nsim_dev->fib_data)) {

drivers/net/netdevsim/netdev.c

@@ -32,8 +32,7 @@ static int nsim_get_port_parent_id(struct net_device *dev,
 {
 	struct netdevsim *ns = netdev_priv(dev);
 
-	ppid->id_len = sizeof(ns->nsim_dev->nsim_bus_dev->dev.id);
-	memcpy(&ppid->id, &ns->nsim_dev->nsim_bus_dev->dev.id, ppid->id_len);
+	memcpy(ppid, &ns->nsim_dev->switch_id, sizeof(*ppid));
 	return 0;
 }
 

drivers/net/netdevsim/netdevsim.h

@@ -141,6 +141,7 @@ struct nsim_dev {
 	u32 prog_id_gen;
 	struct list_head bpf_bound_progs;
 	struct list_head bpf_bound_maps;
+	struct netdev_phys_item_id switch_id;
 };
 
 struct nsim_dev *