[PATCH] mtd: nand: atmel: fix of_irq_get() error check

Thu Aug 10 02:59:20 PDT 2017

Le 2017年8月06日 00:14:28 +0300,
Sergei Shtylyov <sergei.shtylyov at cogentembedded.com> a écrit :
> of_irq_get() may return 0 as well as negative error number on failure,
> while the driver only checks for the negative values. The driver would
> then call devm_request_irq() for IRQ0 in its probe method and never get
> a valid interrupt.
>> Check for 'nc->irq <= 0' instead and return -ENXIO from the driver's probe
> iff of_irq_get() returned 0.
>> Fixes: f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov at cogentembedded.com>
>> ---
> The patch is against the 'master' branch of the 'linux-mtd.git' repo --
> the 'nand/fixes' branch seems too old...
>> drivers/mtd/nand/atmel/nand-controller.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>> Index: linux-mtd/drivers/mtd/nand/atmel/nand-controller.c
> ===================================================================
> --- linux-mtd.orig/drivers/mtd/nand/atmel/nand-controller.c
> +++ linux-mtd/drivers/mtd/nand/atmel/nand-controller.c
> @@ -2078,11 +2078,11 @@ atmel_hsmc_nand_controller_legacy_init(s
> 	}
>> 	nc->irq = of_irq_get(nand_np, 0);
> -	if (nc->irq < 0) {
> -		ret = nc->irq;
> -		if (ret != -EPROBE_DEFER)
> +	if (nc->irq <= 0) {
> +		if (nc->irq != -EPROBE_DEFER)
> 			dev_err(dev, "Failed to get IRQ number (err = %d)\n",
> -				ret);
> +				nc->irq);

nc->irq can be 0 here which doesn't make any sense for an error return
code, so I'd suggest to still use ret and move the 'ret = nc->irq ?:
-ENXIO' line before doing the != -EPROBE_DEFER test.
> +		ret = nc->irq ?: -ENXIO;

Why ENXIO and not EINVAL?
> 		goto out;
> 	}
>> @@ -2168,11 +2168,11 @@ atmel_hsmc_nand_controller_init(struct a
>> 	nc->irq = of_irq_get(np, 0);
> 	of_node_put(np);
> -	if (nc->irq < 0) {
> +	if (nc->irq <= 0) {
> 		if (nc->irq != -EPROBE_DEFER)
> 			dev_err(dev, "Failed to get IRQ number (err = %d)\n",
> 				nc->irq);
> -		return nc->irq;
> +		return nc->irq ?: -ENXIO;
> 	}
>> 	np = of_parse_phandle(dev->of_node, "atmel,nfc-io", 0);
>