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

["Matias Bjørling" <mb@lightnvm.io>]

On 12/04/2021 11.49, Javier González wrote:
> On 12.04.2021 11:26, Matias Bjørling wrote:
>> 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@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?
>>
>
> Yes, please.
>
> I'll crack a beer and cheer on it tonight. Good times :)
>
> Javier

Thank you.