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Date:   Fri, 6 Jan 2023 13:19:34 -0800
From:   Jakub Kicinski <kuba@kernel.org>
To:     Jacob Keller <jacob.e.keller@intel.com>
Cc:     <davem@davemloft.net>, <netdev@vger.kernel.org>,
        <edumazet@google.com>, <pabeni@redhat.com>, <jiri@resnulli.us>
Subject: Re: [PATCH net-next 4/9] devlink: always check if the devlink
 instance is registered
Message-ID: <20230106131934.14e7a900@kernel.org>
In-Reply-To: <9f408a8c-4e23-9de5-0ee8-5deccd901543@intel.com>
References: <20230106063402.485336-1-kuba@kernel.org>
        <20230106063402.485336-5-kuba@kernel.org>
        <9f408a8c-4e23-9de5-0ee8-5deccd901543@intel.com>
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On Fri, 6 Jan 2023 09:03:18 -0800 Jacob Keller wrote:
> > +static inline bool devl_is_registered(struct devlink *devlink)
> > +{
> > +	/* To prevent races the caller must hold the instance lock
> > +	 * or another lock taken during unregistration.
> > +	 */  
> 
> Why not just lockdep_assert here on the instance lock? I guess this
> comment implies that another lock could be used instead but it seems
> weird to allow that? I guess because of things like the linecards_lock
> as opposed to the instance lock?

Yup, as discussed on the RFC - removing the regions lock specifically 
is quite tricky.