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

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Message-ID: <3cef644a-aeb3-ee15-9809-e560f7b24a5c@linux.ibm.com>
Date:   Mon, 3 Jan 2022 11:52:21 +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, Dust Li <dust.li@...ux.alibaba.com>,
        tonylu_linux <tonylu@...ux.alibaba.com>
Subject: Re: [RFC PATCH net] net/smc: Reset conn->lgr when link group
 registration fails

On 30/12/2021 04:50, Wen Gu wrote:
> Thanks for your reply.
> 
> On 2021/12/29 9:07 pm, Karsten Graul wrote:
>> 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.
>> 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?
> Maybe we should try to free the link group when the registration fails, no matter
> it is new created or already existing? If so, is it better to do it in the same
> place like label 'out_unreg'?

I agree with your idea. 

With the proposed change that conn->lgr gets not even set when the registration fails 
we would not need the "conn->lgr = NULL;" after label out_unreg?

And as far as I understand the invocation of smc_lgr_schedule_free_work(lgr) is only
needed after label "create", because when an existing link group was found and the registration
failed then its free work would already be started when no more connections are assigned
to the link group, right?