Messages in this thread | | | Date | Wed, 8 Dec 2021 02:04:32 +0200 | From | Vladimir Oltean <> | Subject | Re: [net-next RFC PATCH 0/6] Add support for qca8k mdio rw in Ethernet packet |
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On Wed, Dec 08, 2021 at 01:47:36AM +0200, Vladimir Oltean wrote: > > 2) is harder. But as far as i know, we have an 1:N setup. One switch > > driver can use N tag drivers. So we need the switch driver to be sure > > the tag driver is what it expects. We keep the shared state in the tag > > driver, so it always has valid data, but when the switch driver wants > > to get a pointer to it, it needs to pass a enum dsa_tag_protocol and > > if it does not match, the core should return -EINVAL or similar. > > In my proposal, the tagger will allocate the memory from its side of the > ->connect() call. So regardless of whether the switch driver side > connects or not, the memory inside dp->priv is there for the tagger to > use. The switch can access it or it can ignore it.
I don't think I actually said something useful here.
The goal would be to minimize use of dp->priv inside the switch driver, outside of the actual ->connect() / ->disconnect() calls. For example, in the felix driver which supports two tagging protocol drivers, I think these two methods would be enough, and they would replace the current felix_port_setup_tagger_data() and felix_port_teardown_tagger_data() calls.
An additional benefit would be that in ->connect() and ->disconnect() we get the actual tagging protocol in use. Currently the felix driver lacks there, because felix_port_setup_tagger_data() just sets dp->priv up unconditionally for the ocelot-8021q tagging protocol (luckily the normal ocelot tagger doesn't need dp->priv).
In sja1105 the story is a bit longer, but I believe that can also be cleaned up to stay within the confines of ->connect()/->disconnect().
So I guess we just need to be careful and push back against dubious use during review.
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