Re: [PATCH 03/20] lightnvm: fix capabilities for 2.0 sysfs

[Javier Gonzalez <javier@cnexlabs.com>]

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> On 22 Feb 2018, at 08.28, Matias Bjørling <mb@lightnvm.io> wrote:
> 
> On 02/21/2018 10:26 AM, Javier González wrote:
>> Both 1.2 and 2.0 specs define a field for media and controller
>> capabilities. Also, 1.2 defines a separate field dedicated to device
>> capabilities.
>> In 2.0 sysfs, this values have been mixed. Revert them to the right
>> value.
>> Signed-off-by: Javier González <javier@cnexlabs.com>
>> ---
>>  drivers/nvme/host/lightnvm.c | 18 +++++++++---------
>>  1 file changed, 9 insertions(+), 9 deletions(-)
>> diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c
>> index 969bb874850c..598abba66f52 100644
>> --- a/drivers/nvme/host/lightnvm.c
>> +++ b/drivers/nvme/host/lightnvm.c
>> @@ -914,8 +914,8 @@ static ssize_t nvm_dev_attr_show(struct device *dev,
>>    	if (strcmp(attr->name, "version") == 0) {
>>  		return scnprintf(page, PAGE_SIZE, "%u\n", dev_geo->ver_id);
>> -	} else if (strcmp(attr->name, "capabilities") == 0) {
>> -		return scnprintf(page, PAGE_SIZE, "%u\n", dev_geo->c.cap);
>> +	} else if (strcmp(attr->name, "media_capabilities") == 0) {
>> +		return scnprintf(page, PAGE_SIZE, "%u\n", dev_geo->c.mccap);
>>  	} else if (strcmp(attr->name, "read_typ") == 0) {
>>  		return scnprintf(page, PAGE_SIZE, "%u\n", dev_geo->c.trdt);
>>  	} else if (strcmp(attr->name, "read_max") == 0) {
>> @@ -993,8 +993,8 @@ static ssize_t nvm_dev_attr_show_12(struct device *dev,
>>  		return scnprintf(page, PAGE_SIZE, "%u\n", dev_geo->c.tbem);
>>  	} else if (strcmp(attr->name, "multiplane_modes") == 0) {
>>  		return scnprintf(page, PAGE_SIZE, "0x%08x\n", dev_geo->c.mpos);
>> -	} else if (strcmp(attr->name, "media_capabilities") == 0) {
>> -		return scnprintf(page, PAGE_SIZE, "0x%08x\n", dev_geo->c.mccap);
>> +	} else if (strcmp(attr->name, "capabilities") == 0) {
>> +		return scnprintf(page, PAGE_SIZE, "0x%08x\n", dev_geo->c.cap);
>>  	} else if (strcmp(attr->name, "max_phys_secs") == 0) {
>>  		return scnprintf(page, PAGE_SIZE, "%u\n", NVM_MAX_VLBA);
>>  	} else {
>> @@ -1055,7 +1055,7 @@ static ssize_t nvm_dev_attr_show_20(struct device *dev,
>>    /* general attributes */
>>  static NVM_DEV_ATTR_RO(version);
>> -static NVM_DEV_ATTR_RO(capabilities);
>> +static NVM_DEV_ATTR_RO(media_capabilities);
>>    static NVM_DEV_ATTR_RO(read_typ);
>>  static NVM_DEV_ATTR_RO(read_max);
>> @@ -1080,12 +1080,12 @@ static NVM_DEV_ATTR_12_RO(prog_max);
>>  static NVM_DEV_ATTR_12_RO(erase_typ);
>>  static NVM_DEV_ATTR_12_RO(erase_max);
>>  static NVM_DEV_ATTR_12_RO(multiplane_modes);
>> -static NVM_DEV_ATTR_12_RO(media_capabilities);
>> +static NVM_DEV_ATTR_12_RO(capabilities);
>>  static NVM_DEV_ATTR_12_RO(max_phys_secs);
>>    static struct attribute *nvm_dev_attrs_12[] = {
>>  	&dev_attr_version.attr,
>> -	&dev_attr_capabilities.attr,
>> +	&dev_attr_media_capabilities.attr,
>>    	&dev_attr_vendor_opcode.attr,
>>  	&dev_attr_device_mode.attr,
>> @@ -1108,7 +1108,7 @@ static struct attribute *nvm_dev_attrs_12[] = {
>>  	&dev_attr_erase_typ.attr,
>>  	&dev_attr_erase_max.attr,
>>  	&dev_attr_multiplane_modes.attr,
>> -	&dev_attr_media_capabilities.attr,
>> +	&dev_attr_capabilities.attr,
>>  	&dev_attr_max_phys_secs.attr,
>>    	NULL,
>> @@ -1134,7 +1134,7 @@ static NVM_DEV_ATTR_20_RO(reset_max);
>>    static struct attribute *nvm_dev_attrs_20[] = {
>>  	&dev_attr_version.attr,
>> -	&dev_attr_capabilities.attr,
>> +	&dev_attr_media_capabilities.attr,
>>    	&dev_attr_groups.attr,
>>  	&dev_attr_punits.attr,
> 
> With the mccap changes, it should make sense to keep the capabilities
> as is.

The change adds mccap, but sysfs points to cap, which is wrong. This
patch is needed. Otherwise, we change the name of mccap to cap, which
is _very_ confusing to people familiar to both specs. We can change
the name of mccap to cap in a future spec revision.

Javier

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