Re: [RFC][PATCH -mm take5 6/7] add ioctls for adding/removing target

From: Satyam Sharma
Date: Thu Jun 21 2007 - 06:09:55 EST


Hi Keiichi,

> Please do consider configfs. Note that we'll have to lose the sysfs
> symlink from your target's kobject to the kobject of the ethernet
> device if we switch to configfs, but was that symlink needed for
> some essential functionality or was it simply for informational
> purpose? IMHO, this patchset only needs to bring in functionality
> to be able to create, destroy, and modify netconsole targets at
> run-time, and all these reconfiguration tasks would be handled
> quite well by configfs, AFAICT.

It was for informational pupose. But, if we used symlink to the net_device
kobject in sysfs, we could easily keep up with changing network device name by
changing symbolic link.

In that case (because it is non-essential) we can drop that link entirely.
(This means the associated code for the temporary modify_list, the
extra mutex and the kasprintf() stuff can also be dropped too!) I guess
the netconsole_event() notifier could now become simply:

if (event == NETDEV_CHANGENAME) {
spin_lock_irqsave(&target_list_lock, ...);
list_for_each_entry(nt, ..., &target_list, ...)
if (nt->np.dev == dev)
strcpy(nt->np.dev_name, dev->name);
spin_unlock_irqrestore(&target_list_lock, ...);
}

In the case of configfs, Do we use config_item related to the network interface
because the configfs doesn't have symlink that refers to net_device kobject
(e.g. "network_interface" in configfs, "network_interface" value is "eth0")?

Yes, that's a good idea, this way we continue to give the information we
were giving previously. We could do this by defining another configfs
attribute of the target's config_item which could then be a proxy for
the char dev_name[IFNAMSIZ] member of the target's underlying netpoll
structure. (this attribute would naturally be read-only from userspace;
sort of similar to what you're doing for the local_mac attribute currently).

Please feel free to discuss anything else regarding this with me off-list,
if you want.

Thanks,
Satyam
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/