Subject: Re: [patch net-next rfc 2/7] net: introduce name_node struct to be used in hashlist

From: Jiri Pirko <[email-masked]>
Date: Fri, 13 Sep 2019 11:52:06 +0200

Fri, Jul 19, 2019 at 10:26:49PM CEST, [email-masked] wrote:
>On Fri, 19 Jul 2019 21:17:40 +0200
>Jiri Pirko <[email-masked]> wrote:
>
>> Fri, Jul 19, 2019 at 06:29:36PM CEST, [email-masked] wrote:
>> >On Fri, 19 Jul 2019 13:00:24 +0200
>> >Jiri Pirko <[email-masked]> wrote:
>> >  
>> >> From: Jiri Pirko <[email-masked]>
>> >> 
>> >> Signed-off-by: Jiri Pirko <[email-masked]>
>> >> ---
>> >>  include/linux/netdevice.h | 10 +++-
>> >>  net/core/dev.c            | 96 +++++++++++++++++++++++++++++++--------
>> >>  2 files changed, 86 insertions(+), 20 deletions(-)
>> >> 
>> >> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>> >> index 88292953aa6f..74f99f127b0e 100644
>> >> --- a/include/linux/netdevice.h
>> >> +++ b/include/linux/netdevice.h
>> >> @@ -918,6 +918,12 @@ struct dev_ifalias {
>> >>  struct devlink;
>> >>  struct tlsdev_ops;
>> >>  
>> >> +struct netdev_name_node {
>> >> +	struct hlist_node hlist;
>> >> +	struct net_device *dev;
>> >> +	char *name  
>> >
>> >You probably can make this const char *  
>
>Don't bother, it looks ok as is. the problem is you would have
>to cast it when calling free.

Actually, it does not. So I'll make it const.

>
>> >Do you want to add __rcu to this list?  
>> 
>> Which list?
>> 
>
>       struct netdev_name_node __rcu *name_node;

This is stored in struct net_device for ifname. The pointer is never
accessed from rcu read.

>
>You might also want to explictly init the hlist node rather
>than relying on the fact that zero is an empty node ptr.
>
> 
> static struct netdev_name_node *netdev_name_node_alloc(struct net_device *dev,
>-                                                      char *name)
>+                                                      const char *name)
> {
>        struct netdev_name_node *name_node;
> 
>-       name_node = kzalloc(sizeof(*name_node), GFP_KERNEL);
>+       name_node = kmalloc(sizeof(*name_node));
>        if (!name_node)
>                return NULL;
>+
>+       INIT_HLIST_NODE(&name_node->hlist);

Will do. Thanks!

>        name_node->dev = dev;
>        name_node->name = name;
>        return name_node;