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

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Message-ID: <20200427220806.13741ec0@xps13>
Date:   Mon, 27 Apr 2020 22:08:06 +0200
From:   Miquel Raynal <miquel.raynal@...tlin.com>
To:     Marek Vasut <marex@...x.de>
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

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

> 
> > 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 ;)

> 
> >> btw would it make sense to split the first three patches of this series
> >> into a separate series ? This rawnand part seems more like an unrelated
> >> cleanup.  
> > 
> > As it seems that the MFD discussion can take longer, then I would say
> > yes, at least for the cleanup/misc changes part.  
> Right
> 

Cheers,
Miquèl