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

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Message-ID: <456b04f5-4ed7-6f3f-b0e6-9276bea09b50@denx.de>
Date:   Mon, 27 Apr 2020 22:10:36 +0200
From:   Marek Vasut <marex@...x.de>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
Cc:     Christophe Kerello <christophe.kerello@...com>, 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 10:08 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.

>>> 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 ;-)