Re: [PATCH 2/5] nvme: register ns_id attributes as default sysfs groups

[Hannes Reinecke <hare@suse.com>]

On 09/05/2018 03:45 PM, Christoph Hellwig wrote:
> On Wed, Sep 05, 2018 at 03:32:03PM +0200, Hannes Reinecke wrote:
>> On 09/05/2018 03:18 PM, Christoph Hellwig wrote:
>>> On Wed, Sep 05, 2018 at 09:00:50AM +0200, Hannes Reinecke wrote:
>>>> We should be registering the ns_id attribute as default sysfs
>>>> attribute groups, otherwise we have a race condition between
>>>> the uevent and the attributes appearing in sysfs.
>>>
>>> Please give Bart credit for his work, as the lightnvm bits are almost
>>> bigger than the rest.
>>>
>> Okay, will be doing so.
>>
>>>> +static umode_t nvm_dev_attrs_visible(struct kobject *kobj,
>>>> +				     struct attribute *attr, int index)
>>>>  {
>>>> +	struct device *dev = container_of(kobj, struct device, kobj);
>>>> +	struct gendisk *disk = dev_to_disk(dev);
>>>> +	struct nvme_ns *ns = disk->private_data;
>>>>  	struct nvm_dev *ndev = ns->ndev;
>>>> +	struct device_attribute *dev_attr =
>>>> +		container_of(attr, typeof(*dev_attr), attr);
>>>>  
>>>> +	if (dev_attr->show == nvm_dev_attr_show)
>>>> +		return attr->mode;
>>>>  
>>>> +	switch (ndev ? ndev->geo.major_ver_id : 0) {
>>>
>>> How could ndev be zero here?
>>>
>> For 'normal' NVMe devices (ie non-lightnvm). As we now register all
>> sysfs attributes (including the lightnvm ones) per default we'll need to
>> blank them out for non-lightnvm devices.
> 
> But then we need to exit early at the beginning of the function,
> as we should not register attributes using nvm_dev_attr_show (or
> anything else for that matter) either.
> 
Okay, will be fixing it up.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		               zSeries & Storage
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