linux-kernel - Re: [PATCH] block:Add proper error handling to the function, disk_add

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Date:	Thu, 14 May 2015 21:41:37 -0400
From:	Jens Axboe <axboe@...nel.dk>
To:	Nicholas Krause <xerofoify@...il.com>
CC:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] block:Add proper error handling to the function, disk_add_events

On 05/14/2015 09:39 PM, Nicholas Krause wrote:
>
>
> On May 14, 2015 9:22:22 PM EDT, Jens Axboe <axboe@...nel.dk> wrote:
>> On 05/14/2015 07:57 PM, Nicholas Krause wrote:
>>> This adds the proper required error checking to the function,
>>> disk_add_events for  when there are no disk events by returning
>>> the error code, -EBUSY. Further this also adds error checking
>>> for when our call to the function, sysfs_create_files by making
>>> this function's return now go into a newly declared variable,
>>> ret and at the end of this function's body return it to indicate
>>> whether this function is successful or not to the caller.
>>>
>>> Signed-off-by: Nicholas Krause <xerofoify@...il.com>
>>> ---
>>>    block/genhd.c | 13 +++++++++----
>>>    1 file changed, 9 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/block/genhd.c b/block/genhd.c
>>> index 0a536dc..3eb7ee9 100644
>>> --- a/block/genhd.c
>>> +++ b/block/genhd.c
>>> @@ -1803,15 +1803,19 @@ static void disk_alloc_events(struct gendisk
>> *disk)
>>>    	disk->ev = ev;
>>>    }
>>>
>>> -static void disk_add_events(struct gendisk *disk)
>>> +static int disk_add_events(struct gendisk *disk)
>>>    {
>>> +	int ret = 0;
>>>    	if (!disk->ev)
>>> -		return;
>>> +		return -EBUSY;
>>> +
>>> +	ret = sysfs_create_files(&disk_to_dev(disk)->kobj,
>> disk_events_attrs)
>>>
>>> -	/* FIXME: error handling */
>>> -	if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs)
>> < 0)
>>> +	if (!ret) {
>>>    		pr_warn("%s: failed to create sysfs files for events\n",
>>>    			disk->disk_name);
>>> +		return ret;
>>> +	}
>>
>> You didn't even test this, obviously.
> It builds on my system.  I can't see anything wrong with it, please explain.

The fact that it compiles does not constitute that it has been tested. 
And it's definitely broken, as a test boot would have revealed.

-- 
Jens Axboe

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