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Date: Tue, 23 Jun 2015 08:27:45 +0200
From: Richard Weinberger <richard@nod.at>
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To: Brian Norris <computersforpeace@gmail.com>
Subject: Re: [PATCH 6/6] mtd: docg3: Don't do ERR_PTR(0)
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Am 17.06.2015 um 20:41 schrieb Brian Norris:
> On Mon, Jun 01, 2015 at 11:10:54PM +0200, Richard Weinberger wrote:
>> Don't return a obfuscated null pointer using ERR_PTR(0).
>> If the no device is found clearly return -ENODEV.
>> This makes the code more clear and matches the comment
>> of doc_probe_device().
>>
>> Signed-off-by: Richard Weinberger <richard@nod.at>
>> ---
> 
> Have you tested this patch?

nah, I don't own such a device.

>>  drivers/mtd/devices/docg3.c | 16 ++++++----------
>>  1 file changed, 6 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
>> index 5e67b4a..630e29a 100644
>> --- a/drivers/mtd/devices/docg3.c
>> +++ b/drivers/mtd/devices/docg3.c
>> @@ -1902,7 +1902,7 @@ doc_probe_device(struct docg3_cascade *cascade, int floor, struct device *dev)
>>  	chip_id = doc_register_readw(docg3, DOC_CHIPID);
>>  	chip_id_inv = doc_register_readw(docg3, DOC_CHIPID_INV);
>>  
>> -	ret = 0;
>> +	ret = -ENODEV;
>>  	if (chip_id != (u16)(~chip_id_inv)) {
>>  		goto nomem4;
>>  	}
>> @@ -2068,13 +2068,10 @@ static int __init docg3_probe(struct platform_device *pdev)
>>  		mtd = doc_probe_device(cascade, floor, dev);
>>  		if (IS_ERR(mtd)) {
>>  			ret = PTR_ERR(mtd);
>> -			goto err_probe;
>> -		}
>> -		if (!mtd) {
>> -			if (floor == 0)
>> -				goto notfound;
>> -			else
>> +			if (ret == -ENODEV && floor == 0)
> 
> I think you might have changed the logic when refactoring here. I think
> the right refactoring would be the following, no?
> 
> 			if (ret == -ENODEV && floor != 0)
> 				continue;
> 			else
> 				goto err_probe;
> 

You are right, the logic changed. ;-\
Please drop this patch, I'll resend it for 4.3.

Thanks,
//richard