Re: [PATCH net] net: dsa: Fix load order between DSA drivers and taggers

[David Miller <davem@davemloft.net>]

From: Andrew Lunn <andrew@lunn.ch>
Date: Thu, 12 Sep 2019 15:16:45 +0200

> The DSA core, DSA taggers and DSA drivers all make use of
> module_init(). Hence they get initialised at device_initcall() time.
> The ordering is non-deterministic. It can be a DSA driver is bound to
> a device before the needed tag driver has been initialised, resulting
> in the message:
> 
> No tagger for this switch
> 
> Rather than have this be fatal, return -EPROBE_DEFER so that it is
> tried again later once all the needed drivers have been loaded.
> 
> Fixes: d3b8c04988ca ("dsa: Add boilerplate helper to register DSA tag driver modules")
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> ---
> 
> I did wonder if we should play with the core and tag drivers and make
> them use subsystem_initcall(), but EPROBE_DEFER seems to be the more
> preferred solution nowadays.

Yes that does indeed seem preferable these days and all of the init
types is usually quite fragile.

Applied and queued up for v5.2 -stable.

Thanks.