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Date:   Sat, 4 Jun 2022 14:59:55 +0100
From:   Jonathan Cameron <jic23@kernel.org>
To:     Dmitry Rokosov <DDRokosov@sberdevices.ru>
Cc:     "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "lars@metafoo.de" <lars@metafoo.de>,
        "andy.shevchenko@gmail.com" <andy.shevchenko@gmail.com>,
        "noname.nuno@gmail.com" <noname.nuno@gmail.com>,
        "linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
        kernel <kernel@sberdevices.ru>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH v1] iio: trigger: move trig->owner init to trigger
 allocate() stage
Message-ID: <20220604145955.2a1108ca@jic23-huawei>
In-Reply-To: <20220601174837.20292-1-ddrokosov@sberdevices.ru>
References: <20220601174837.20292-1-ddrokosov@sberdevices.ru>
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On Wed, 1 Jun 2022 17:48:32 +0000
Dmitry Rokosov <DDRokosov@sberdevices.ru> wrote:

> To provide a new IIO trigger to the IIO core, usually driver executes the
> following pipeline: allocate()/register()/get(). Before, IIO core assigned
> trig->owner as a pointer to the module which registered this trigger at
> the register() stage. But actually the trigger object is owned by the
> module earlier, on the allocate() stage, when trigger object is
> successfully allocated for the driver.
> 
> This patch moves trig->owner initialization from register()
> stage of trigger initialization pipeline to allocate() stage to
> eliminate all misunderstandings and time gaps between trigger object
> creation and owner acquiring.
> 
> Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>

Hi Dmitry,

I 'think' this is fine, but its in the high risk category that I'd like
to keep it on list for a few weeks before applying.

Note I'm still keen that in general we keep the flow such that
we do allocate()/register()/get() as there is no guarantee that the get()
will never do anything that requires the trigger to be registered, even
though that is true today.  Which is another way of saying I'm still
keen we fix up any cases that sneak in after your fix up set dealt with
the current ones.

Thanks for following up on this!

Jonathan