Re: [RFC] [PATCH] clean up nf_log API

[Philip Craig <philipc@snapgear.com>]

On 05/11/2006 06:25 PM, Harald Welte wrote:
> I agree, I prefer automatic fallback while giving the user the ability
> to unload.  However, if people automatically unload 'unused' modules,
> then there might be a problem (however, for both ULOG and nfnetlink_log,
> userspace listeners would increment the refcount, I think).

What constitutes in use?  If a backend is in use whenever it is
the highest priority backend, then blocking unloading would mean
nfnetlink_log can never be unloaded.  Letting the user choose the
highest priority backend would solve that.  In which case I think
blocking unloading is desirable, we shouldn't unload the backend
the user has chosen.

And I assume that log rules can also specify a backend? (eg the
LOG and ULOG rules always will)  That should probably block
unloading too.

> Also, there is another unresolved problem:  What if we actually have
> e.g. nfnetlink_log loaded, but it is unable to send a specific packet to
> userspace because there is no listener for this Address family or log
> group?   Should we then also fall back on some other backend?

Just doing a printk to notify of the error is enough?
We probably should be doing a printk anyway if it is
a backend the user has chosen explicitly.