netdev - Re: [RFC PATCH net] net/smc: Reset conn->lgr when link group registration fails

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Message-ID: <07930fec-4109-0dfd-7df4-286cb56ec75b@linux.ibm.com>
Date:   Wed, 29 Dec 2021 14:07:11 +0100
From:   Karsten Graul <kgraul@...ux.ibm.com>
To:     Wen Gu <guwen@...ux.alibaba.com>, davem@...emloft.net,
        kuba@...nel.org
Cc:     linux-s390@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH net] net/smc: Reset conn->lgr when link group
 registration fails

On 28/12/2021 08:49, Wen Gu wrote:
> SMC connections might fail to be registered to a link group due to
> things like unable to find a link to assign to in its creation. As
> a result, connection creation will return a failure and most
> resources related to the connection won't be applied or initialized,
> such as conn->abort_work or conn->lnk.

I agree with your fix to set conn->lgr to NULL when smc_lgr_register_conn() fails.

It would probably be better to have smc_lgr_register_conn() set conn->lgr instead to set
it before in smc_conn_create(). So it would not be set at all then the registration failes.

What I do not understand is the extra step after the new label out_unreg: that 
may invoke smc_lgr_schedule_free_work(). You did not talk about that one.
Is the idea to have a new link group get freed() when a connection could not
be registered on it? In that case I would expect this code after label create:
in smc_lgr_create(), when the rc from smc_lgr_register_conn() is not zero.
Thoughts?