linux-kernel - Re: [PATCH v4 15/16] block: sed-opal: don't repeat opal

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Message-ID: <alpine.LRH.2.21.1902101840020.28071@linux.fjfi.cvut.cz>
Date:   Sun, 10 Feb 2019 18:46:18 +0100 (CET)
From:   David Kozub <zub@...ux.fjfi.cvut.cz>
To:     "Derrick, Jonathan" <jonathan.derrick@...el.com>
cc:     "hch@...radead.org" <hch@...radead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-block@...r.kernel.org" <linux-block@...r.kernel.org>,
        "sbauer@...donthack.me" <sbauer@...donthack.me>,
        "jonas.rabenstein@...dium.uni-erlangen.de" 
        <jonas.rabenstein@...dium.uni-erlangen.de>,
        "axboe@...nel.dk" <axboe@...nel.dk>
Subject: Re: [PATCH v4 15/16] block: sed-opal: don't repeat opal_discovery0
 in each steps array

On Fri, 8 Feb 2019, Derrick, Jonathan wrote:

> On Mon, 2019-02-04 at 23:44 +0100, David Kozub wrote:
>> On Mon, 4 Feb 2019, Christoph Hellwig wrote:
>>
>>>> +	/* first do a discovery0 */
>>>> +	error = opal_discovery0_step(dev);
>>>>
>>>> +	for (state = 0; !error && state < n_steps; state++)
>>>> +		error = execute_step(dev, &steps[state], state);
>>>> +
>>>> +	/*
>>>> +	 * For each OPAL command the first step in steps starts some sort of
>>>> +	 * session. If an error occurred in the initial discovery0 or if an
>>>> +	 * error occurred in the first step (and thus stopping the loop with
>>>> +	 * state == 1) then there was an error before or during the attempt to
>>>> +	 * start a session. Therefore we shouldn't attempt to terminate a
>>>> +	 * session, as one has not yet been created.
>>>> +	 */
>>>> +	if (error && state > 1)
>>>> +		end_opal_session_error(dev);
>>>>
>>>>  	return error;
>>>
>>> The flow here is a little too condensed for my taste.  Why not the
>>> plain obvoious, if a little longer:
>>>
>>> 	error = error = opal_discovery0_step(dev);
>>> 	if (error)
>>> 		return error;
>>>
>>> 	for (state = 0; state < n_steps; state++) {
>>> 		error = execute_step(dev, &steps[state], state);
>>> 		if (error)
>>> 			goto out_error;
>>> 	}
>>>
>>> 	return 0;
>>>
>>> out_error:
>>> 	if (state > 1)
>>> 		end_opal_session_error(dev);
>>> 	return error;
>>
>> No problem, I can use this version. But I think there is a minor issue -
>> the same one I hit in my original change, just from the other direction:
>>
>> If the loop succeds for the 0-th element of steps, and then fails for the
>> 1st element, then state equals 1 yet the session has been started, so we
>> should close it.
>>
>> I think the condition in out_error should be if (state > 0).
>>
>> Best regards,
>> David
> Looks good with Christoph's suggestion (for 14/16) and your state check fix
>
>
> Reviewed-by: Jon Derrick <jonathan.derrick@...el.com>

Hi Jon,

What suggestion by Christoph you have in mind? I don't see any for 14/16. 
Currently, in my git repo, for this patch, I applied Christoph suggestion 
for this (15/16) patch + the "state > 0" fix. Is this what you mean?

Best regards,
David