linux-kernel - Re: [PATCH v2 04/12] mtd: rawnand: stm32_fmc2: manage all errors cases at probe time

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Message-ID: <506961d9-4852-c926-3446-f5e8b27e5c2e@st.com>
Date:   Wed, 29 Apr 2020 10:00:01 +0200
From:   Christophe Kerello <christophe.kerello@...com>
To:     Marek Vasut <marex@...x.de>,
        Miquel Raynal <miquel.raynal@...tlin.com>
CC:     <richard@....at>, <vigneshr@...com>, <lee.jones@...aro.org>,
        <robh+dt@...nel.org>, <mark.rutland@....com>, <tony@...mide.com>,
        <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <devicetree@...r.kernel.org>
Subject: Re: [PATCH v2 04/12] mtd: rawnand: stm32_fmc2: manage all errors
 cases at probe time



On 4/27/20 10:10 PM, Marek Vasut wrote:
> On 4/27/20 10:08 PM, Miquel Raynal wrote:
>> Hi Marek,
>>
>> Marek Vasut <marex@...x.de> wrote on Mon, 27 Apr 2020 21:46:44 +0200:
>>
>>> On 4/27/20 8:08 PM, Miquel Raynal wrote:
>>> [...]
>>>>>>>   	/* FMC2 init routine */
>>>>>>>   	stm32_fmc2_init(fmc2);
>>>>>>> @@ -1997,7 +2001,7 @@ static int stm32_fmc2_probe(struct platform_device *pdev)
>>>>>>>   	/* Scan to find existence of the device */
>>>>>>>   	ret = nand_scan(chip, nand->ncs);
>>>>>>>   	if (ret)
>>>>>>> -		goto err_scan;
>>>>>>> +		goto err_dma_setup;
>>>>>>>   
>>>>>>>   	ret = mtd_device_register(mtd, NULL, 0);
>>>>>>>   	if (ret)
>>>>>>> @@ -2010,7 +2014,7 @@ static int stm32_fmc2_probe(struct platform_device *pdev)
>>>>>>>   err_device_register:
>>>>>>>   	nand_cleanup(chip);
>>>>>>>   
>>>>>>> -err_scan:
>>>>>>> +err_dma_setup:
>>>>>>>   	if (fmc2->dma_ecc_ch)
>>>>>>>   		dma_release_channel(fmc2->dma_ecc_ch);
>>>>>>>   	if (fmc2->dma_tx_ch)
>>>>>>> @@ -2021,6 +2025,7 @@ static int stm32_fmc2_probe(struct platform_device *pdev)
>>>>>>>   	sg_free_table(&fmc2->dma_data_sg);
>>>>>>>   	sg_free_table(&fmc2->dma_ecc_sg);
>>>>>>>   
>>>>>>> +err_clk_disable:
>>>>>>>   	clk_disable_unprepare(fmc2->clk);
>>>>>>>   
>>>>>>>   	return ret;
>>>>>>
>>>>>> I didn't spot it during my earlier reviews but I really prefer using
>>>>>> labels explaining what you do than having the same name of the function
>>>>>> which failed. This way you don't have to rework the error path when
>>>>>> you handle an additional error.
>>>>>>
>>>>>> So, would you mind doing this in two steps:
>>>>>>
>>>>>> 1/
>>>>>> Replace
>>>>>>
>>>>>>      err_scan:
>>>>>>
>>>>>> with, eg.
>>>>>>
>>>>>>      release_dma_objs:
>>>>>
>>>>> The ^err_ prefix in failpath labels is useful, since it's easily
>>>>> possible to match on it with regexes ; not so much on arbitrary label name.
>>>>
>>>> I guess so, but is it actually useful to catch labels in a regex? (real
>>>> question)
>>>
>>> I find it useful to have a unified way to find those labels, e.g.
>>> err_because_foo:
>>> err_because_bar:
>>> err_last_one:
>>> is much nicer than:
>>> foo_failed:
>>> bar_also_failed:
>>> its_total_randomness:
>>
>> My point being, Christophe, you can use err_ as a prefix but I think
>> it's better to use:
>>
>>      err_do_this_cleanup
>>
>> than
>>
>>     err_this_failed
> 
> That's fine either way.

Hi Miquel,

I will rename the label in v3:
  - err_device_register => err_nand_cleanup
  - err_dma_setup => err_release_dma
  - err_clk_disable => will keep this one

Regards,
Christophe Kerello.

> 
>>>> Any way I suppose catching ":\n" is already a good approximation to
>>>> find labels?
>>>
>>> Not very practical with git grep (^err.*: works nicely though)
>>
>> I suppose ^.*:$ would work the same ;)
> 
> Try and see how much other irrelevant stuff that sucks in ;-)
>