Subject: Re: [PATCH net-next 2/2] devlink: Allocate devlink directly in requested net namespace

From: Leon Romanovsky <[email-masked]>
Date: Thu, 29 Jul 2021 15:06:36 +0300

On Thu, Jul 29, 2021 at 01:55:29PM +0200, Jiri Pirko wrote:
> Thu, Jul 29, 2021 at 10:15:26AM CEST, [email-masked] wrote:
> >From: Leon Romanovsky <[email-masked]>
> >
> >There is no need in extra call indirection and check from impossible
> >flow where someone tries to set namespace without prior call
> >to devlink_alloc().
> >
> >Instead of this extra logic and additional EXPORT_SYMBOL, use specialized
> >devlink allocation function that receives net namespace as an argument.
> >
> >Such specialized API allows clear view when devlink initialized in wrong
> >net namespace and/or kernel users don't try to change devlink namespace
> >under the hood.
> >
> >Signed-off-by: Leon Romanovsky <[email-masked]>
> >---
> > drivers/net/netdevsim/dev.c |  4 ++--
> > include/net/devlink.h       | 14 ++++++++++++--
> > net/core/devlink.c          | 26 ++++++++------------------
> > 3 files changed, 22 insertions(+), 22 deletions(-)
> >
> >diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
> >index 6348307bfa84..d538a39d4225 100644
> >--- a/drivers/net/netdevsim/dev.c
> >+++ b/drivers/net/netdevsim/dev.c
> >@@ -1431,10 +1431,10 @@ int nsim_dev_probe(struct nsim_bus_dev *nsim_bus_dev)
> > 	struct devlink *devlink;
> > 	int err;
> > 
> >-	devlink = devlink_alloc(&nsim_dev_devlink_ops, sizeof(*nsim_dev));
> >+	devlink = devlink_alloc_ns(&nsim_dev_devlink_ops, sizeof(*nsim_dev),
> >+				   nsim_bus_dev->initial_net);
> > 	if (!devlink)
> > 		return -ENOMEM;
> >-	devlink_net_set(devlink, nsim_bus_dev->initial_net);
> > 	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);
> >diff --git a/include/net/devlink.h b/include/net/devlink.h
> >index e48a62320407..b4691c40320f 100644
> >--- a/include/net/devlink.h
> >+++ b/include/net/devlink.h
> >@@ -1540,8 +1540,18 @@ static inline struct devlink *netdev_to_devlink(struct net_device *dev)
> > struct ib_device;
> > 
> > struct net *devlink_net(const struct devlink *devlink);
> >-void devlink_net_set(struct devlink *devlink, struct net *net);
> >-struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t priv_size);
> >+/* This RAW call is intended for software devices that can
> 
> Not sure what "RAW call" is, perhaps you can just avoid this here.

I wanted to emphasize the message that we shouldn't see this call in
regular drivers and it is very specific to SW drivers.

I'll drop "RAW".

> 
> Otherwise, this patch looks fine to me:
> Reviewed-by: Jiri Pirko <[email-masked]>

Thanks

> [...]