2011/6/23 Michal Nazarewicz <mina86@xxxxxxxxxx>:
> On Thu, 23 Jun 2011 13:13:58 +0200, Amit Nagal <helloin.amit@xxxxxxxxx>
> wrote:
>>
>> while going through skel_release() code in usb-skeleton driver , i
>> noticed the following statements :
>>
>> static int skel_release(struct inode *inode, struct file *file)
>> {
>> struct usb_skel *dev;
>>
>> dev = file->private_data;
>>
>> if (dev == NULL)
>> return -ENODEV;
>>
>> .......
>> }
>>
>> but i am trying to understand the scenario where ( dev == NULL ) can
>> come true and skel_release() returns -ENODEV .
>>
>> since in skel_open() , file->private_data saves dev with (
>> file->private_data = dev ) statement ,
>
> Not always. There are two “goto exit” statements that will skip setting
> of the file->private_data.
>
Ya , but "goto exit" are there to handle error conditions , which
will finally lead to failure of open() call in userspace .
since open() fails , application wont get valid fd for calling
close() , and thus skel_release won't execute at all .
Regards
Amit Nagal
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