[PATCH] lightnvm: deprecated OCSSD support and schedule it for removal in Linux 5.15

[Matias Bjørling]

On 12/04/2021 11.21, Matias Bjørling wrote:
> On 12/04/2021 10.12, Christoph Hellwig wrote:
>> Lightnvm was an innovative idea to expose more low-level control over 
>> SSDs.
>> But it failed to get properly standardized and remains a non-standarized
>> extension to NVMe that requires vendor specific quirks for a few now 
>> mostly
>> obsolete SSD devices.  The standardized ZNS command set for NVMe has 
>> take
>> over a lot of the approaches and allows for fully standardized 
>> operation.
>>
>> Remove the Linux code to support open channel SSDs as the few production
>> deployments of the above mentioned SSDs are using userspace driver 
>> stacks
>> instead of the fairly limited Linux support.
>>
>> Signed-off-by: Christoph Hellwig <hch at lst.de>
>> ---
>>   drivers/lightnvm/Kconfig | 4 +++-
>>   drivers/lightnvm/core.c  | 2 ++
>>   2 files changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/lightnvm/Kconfig b/drivers/lightnvm/Kconfig
>> index 4c2ce210c1237d..04caa0f2d445c7 100644
>> --- a/drivers/lightnvm/Kconfig
>> +++ b/drivers/lightnvm/Kconfig
>> @@ -4,7 +4,7 @@
>>   #
>>     menuconfig NVM
>> -    bool "Open-Channel SSD target support"
>> +    bool "Open-Channel SSD target support (DEPRECATED)"
>>       depends on BLOCK
>>       help
>>         Say Y here to get to enable Open-channel SSDs.
>> @@ -15,6 +15,8 @@ menuconfig NVM
>>         If you say N, all options in this submenu will be skipped and 
>> disabled
>>         only do this if you know what you are doing.
>>   +      This code is deprecated and will be removed in Linux 5.15.
>> +
>>   if NVM
>>     config NVM_PBLK
>> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
>> index 28ddcaa5358b14..4394f47c81296a 100644
>> --- a/drivers/lightnvm/core.c
>> +++ b/drivers/lightnvm/core.c
>> @@ -1174,6 +1174,8 @@ int nvm_register(struct nvm_dev *dev)
>>   {
>>       int ret, exp_pool_size;
>>   +    pr_warn_once("lightnvm support is deprecated and will be 
>> removed in Linux 5.15.\n");
>> +
>>       if (!dev->q || !dev->ops) {
>>           kref_put(&dev->ref, nvm_free);
>>           return -EINVAL;
>
> Thanks, Christoph.
>
> I'll send it to Jens with today's lightnvm PR.

Javier, can I add your reviewed-by?

Thank you.