From mboxrd@z Thu Jan  1 00:00:00 1970
From: vikram186@gmail.com (Vikram Narayanan)
Date: Wed, 4 May 2011 21:56:37 +0530
Subject: Confusion in kobjects
Message-ID: <BANLkTinFCBxL-JKiO4HSnNvCoaN6GZ529w@mail.gmail.com>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

> On Wed, May 04, 2011 at 07:26:44PM +0530, Vikram Narayanan wrote:
>> The kernel doc (kobject.txt) says that
>>
>> "No structure should EVER have more than one kobject embedded within it.
>> ?If it does, the reference counting for the object is sure to be messed
>> ?up and incorrect, and your code will be buggy. ?So do not do this. "
>>
>> But in the file drivers/uio/uio.c, a structure has two such kobjects.
>>
>> struct uio_device {
>> ? ? ? ? ?struct module ? ? ? ? ? *owner;
>> ? ? ? ? ?struct device ? ? ? ? ? *dev;
>> ? ? ? ? ?int ? ? ? ? ? ? ? ? ? ? minor;
>> ? ? ? ? ?atomic_t ? ? ? ? ? ? ? ?event;
>> ? ? ? ? ?struct fasync_struct ? ?*async_queue;
>> ? ? ? ? ?wait_queue_head_t ? ? ? wait;
>> ? ? ? ? ?int ? ? ? ? ? ? ? ? ? ? vma_count;
>> ? ? ? ? ?struct uio_info ? ? ? ? *info;
>> ? ? ? ? ?struct kobject ? ? ? ? ?*map_dir;
>> ? ? ? ? ?struct kobject ? ? ? ? ?*portio_dir;
>> ?};
>>
>> So, What is the exception for this structure? Is this right? If yes,
>> can someone explain why it is right, and where should we use it?
>
> There are not more than one kobject _IN_ the structure. ?It merely
> has pointers to more than one kobject (three actually), which is fine to
> do.
Thanks for the clarification. Think I have to go for an eye checkup ;)

Thanks,
Vikram