Re: [PATCH v3] ubifs: make ubifs_[get|set]xattr atomic

[Dongsheng Yang <yangds.fnst@cn.fujitsu.com>]

On 08/11/2015 08:57 PM, Artem Bityutskiy wrote:
> On Fri, 2015-08-07 at 14:07 +0800, Dongsheng Yang wrote:
>> +	mutex_lock(&ui->ui_mutex);
>>   	kfree(ui->data);
>>   	ui->data = kmemdup(value, size, GFP_NOFS);
>>   	if (!ui->data) {
>> +		mutex_unlock(&ui->ui_mutex);
>>   		err = -ENOMEM;
>>   		goto out_free;
>>   	}
>>   	inode->i_size = ui->ui_size = size;
>>   	ui->data_len = size;
>> +	mutex_unlock(&ui->ui_mutex);
>
>
> Just one note - should kmemdup() be called outside of the critical
> section, to make is shorter (memory allocation is a potentially slow
> operation)?
>
> Something like:
>
> buf = kmemdup()
> mutex_lock()
> kfree(ui->data)
> ui->data = buf
> mutex_unlock()

Good point, will update it.

Yang
>
> Artem.
>