Re: [PATCH 1/2] platform: make platform_get_irq_optional() optional

[Uwe Kleine-König]

On Mon, Jan 17, 2022 at 02:57:32PM +0300, Sergey Shtylyov wrote:
> On 1/10/22 10:54 PM, Sergey Shtylyov wrote:
> 
> > This patch is based on the former Andy Shevchenko's patch:
> > 
> > https://lore.kernel.org/lkml/20210331144526.19439-1-andriy.shevchenko@xxxxxxxxxxxxxxx/
> > 
> > Currently platform_get_irq_optional() returns an error code even if IRQ
> > resource simply has not been found. It prevents the callers from being
> > error code agnostic in their error handling:
> > 
> > 	ret = platform_get_irq_optional(...);
> > 	if (ret < 0 && ret != -ENXIO)
> > 		return ret; // respect deferred probe
> > 	if (ret > 0)
> > 		...we get an IRQ...
> > 
> > All other *_optional() APIs seem to return 0 or NULL in case an optional
> > resource is not available. Let's follow this good example, so that the
> > callers would look like:
> > 
> > 	ret = platform_get_irq_optional(...);
> > 	if (ret < 0)
> > 		return ret;
> > 	if (ret > 0)
> > 		...we get an IRQ...
> > 
> > Reported-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
> > Signed-off-by: Sergey Shtylyov <s.shtylyov@xxxxxx>
> [...]
> 
>    Please don't merge this as yet, I'm going thru this patch once again
> and have already found some sloppy code. :-/

Who would you expect to merge this? I would have expected Greg, but he
seems to have given up this thread.

> > diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
> > index 7450904e330a..fdc63bfa5be4 100644
> > --- a/drivers/char/ipmi/bt-bmc.c
> > +++ b/drivers/char/ipmi/bt-bmc.c
> > @@ -382,12 +382,14 @@ static int bt_bmc_config_irq(struct bt_bmc *bt_bmc,
> >  	bt_bmc->irq = platform_get_irq_optional(pdev, 0);
> >  	if (bt_bmc->irq < 0)
> >  		return bt_bmc->irq;
> > +	if (!bt_bmc->irq)
> > +		return 0;
> 
>    Hm, this is sloppy. Will recast and rebase to the -next branch.

I didn't think about what you mean with sloppy, but the code is
equivalent to

	if (bt_bmc->irq <= 0)
		return bt_bmc->irq; 

> >  
> >  	rc = devm_request_irq(dev, bt_bmc->irq, bt_bmc_irq, IRQF_SHARED,
> >  			      DEVICE_NAME, bt_bmc);
> >  	if (rc < 0) {
> >  		dev_warn(dev, "Unable to request IRQ %d\n", bt_bmc->irq);
> > -		bt_bmc->irq = rc;
> > +		bt_bmc->irq = 0;
> 
>    This change isn't needed...
> 
> >  		return rc;
> >  	}
> >  
> [...]
> > diff --git a/drivers/edac/xgene_edac.c b/drivers/edac/xgene_edac.c
> > index 2ccd1db5e98f..0d1bdd27cd78 100644
> > --- a/drivers/edac/xgene_edac.c
> > +++ b/drivers/edac/xgene_edac.c
> > @@ -1917,7 +1917,7 @@ static int xgene_edac_probe(struct platform_device *pdev)
> >  
> >  		for (i = 0; i < 3; i++) {
> >  			irq = platform_get_irq_optional(pdev, i);
> 
>    Is *_optinal() even correct here?

_optinal isn't correct, _optional maybe is. :-)
Anyhow, look at e26124cd5f7099949109608845bba9e9bf96599c, the driver was
fixed not to print two error messages and the wrong option was picked.

> > -			if (irq < 0) {
> > +			if (irq <= 0) {
> >  				dev_err(&pdev->dev, "No IRQ resource\n");
> >  				rc = -EINVAL;
> >  				goto out_err;

What's wrong here is that the return code is hardcoded ...

> [...]
> > diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> > index f75929783b94..ac222985efde 100644
> > --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> > +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> > @@ -1521,7 +1521,7 @@ static irqreturn_t brcmnand_ctlrdy_irq(int irq, void *data)
> >  
> >  	/* check if you need to piggy back on the ctrlrdy irq */
> >  	if (ctrl->edu_pending) {
> > -		if (irq == ctrl->irq && ((int)ctrl->edu_irq >= 0))
> > +		if (irq == ctrl->irq && ((int)ctrl->edu_irq > 0))
> 
>    Note to self: the cast to *int* isn't needed, the edu_irq field is *int* already...
> 
> [...]
> > diff --git a/drivers/power/supply/mp2629_charger.c b/drivers/power/supply/mp2629_charger.c
> > index bdf924b73e47..51289700a7ac 100644
> > --- a/drivers/power/supply/mp2629_charger.c
> > +++ b/drivers/power/supply/mp2629_charger.c
> > @@ -581,9 +581,9 @@ static int mp2629_charger_probe(struct platform_device *pdev)
> >  	platform_set_drvdata(pdev, charger);
> >  
> >  	irq = platform_get_irq_optional(to_platform_device(dev->parent), 0);
> 
>    Again, is *_optional() even correct here?
> 
> > -	if (irq < 0) {
> > +	if (irq <= 0) {
> >  		dev_err(dev, "get irq fail: %d\n", irq);
> > -		return irq;
> > +		return irq < 0 ? irq : -ENXIO;

Ack, could be simplified by switching to platform_get_irq().

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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