Re: [patch net-next 3/3] netdevsim: create devlink and netdev instances in namespace

Mon, Jul 29, 2019 at 08:59:06PM CEST, jakub.kicinski@netronome.com wrote:

On Sat, 27 Jul 2019 11:44:59 +0200, Jiri Pirko wrote:

quoted

From: Jiri Pirko <redacted>

When user does create new netdevsim instance using sysfs bus file,
create the devlink instance and related netdev instance in the namespace
of the caller.

Signed-off-by: Jiri Pirko <redacted>

quoted

diff --git a/drivers/net/netdevsim/bus.c b/drivers/net/netdevsim/bus.c
index 1a0ff3d7747b..6aeed0c600f8 100644
--- a/drivers/net/netdevsim/bus.c
+++ b/drivers/net/netdevsim/bus.c

@@ -283,6 +283,7 @@ nsim_bus_dev_new(unsigned int id, unsigned int port_count)
 	nsim_bus_dev->dev.bus = &nsim_bus;
 	nsim_bus_dev->dev.type = &nsim_bus_dev_type;
 	nsim_bus_dev->port_count = port_count;
+	nsim_bus_dev->initial_net = current->nsproxy->net_ns;
 
 	err = device_register(&nsim_bus_dev->dev);
 	if (err)

The saved initial_net is only to carry the net info from the adding
process to the probe callback, because probe can be asynchronous?

Exactly.

I'm not entirely sure netdevsim can probe asynchronously in practice
given we never return EPROBE_DEFER, but would you mind at least adding
a comment stating that next to the definition of the field, otherwise 
I worry someone may mistakenly use this field instead of the up-to-date
devlink's netns.

Will do.

quoted

diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index 79c05af2a7c0..cdf53d0e0c49 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h

@@ -19,6 +19,7 @@
 #include <linux/netdevice.h>
 #include <linux/u64_stats_sync.h>
 #include <net/devlink.h>
+#include <net/net_namespace.h>

You can just do a forward declaration, no need to pull in the header.

Sure, but why?

quoted

 #include <net/xdp.h>
 
 #define DRV_NAME	"netdevsim"

quoted

@@ -213,6 +215,7 @@ struct nsim_bus_dev {
 	struct device dev;
 	struct list_head list;
 	unsigned int port_count;
+	struct net *initial_net;
 	unsigned int num_vfs;
 	struct nsim_vf_config *vfconfigs;
 };

Otherwise makes perfect sense, with the above nits addressed feel free
to add:

Acked-by: Jakub Kicinski <redacted>