Re: [PATCH net-next v5 04/10] ethtool: Add flashing transceiver modules' firmware notifications ability

[Jakub Kicinski <kuba@kernel.org>]

On Wed, 22 May 2024 13:08:43 +0000 Danielle Ratson wrote:
> 1. Add a new unicast function to netlink.c:
> void *ethnl_unicast_put(struct sk_buff *skb, u32 portid, u32 seq, u8 cmd)
> 
> 2. Use it in the notification function instead of the multicast previously used along with genlmsg_unicast().
> 'portid' and 'seq' taken from genl_info(), are added to the struct ethtool_module_fw_flash, which is accessible from the work item.
> 
> 3. Create a global list that holds nodes from type struct ethtool_module_fw_flash() and add it as a field in the struct ethtool_module_fw_flash.
> Before scheduling a work, a new node is added to the list.

Makes sense.

> 4. Add a new netlink notifier that when the relevant event takes place, deletes the node from the list, wait until the end of the work item, with cancel_work_sync() and free allocations.

What's the "relevant event" in this case? Closing of the socket that
user had issued the command on?

Easiest way to "notice" the socket got closed would probably be to
add some info to genl_sk_priv_*(). ->sock_priv_destroy() will get
called. But you can also get a close notification in the family 
->unbind callback.

I'm on the fence whether we should cancel the work. We could just
mark the command as 'no socket present' and stop sending notifications.
Not sure which is better..