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

[Javier González]

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 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?
>

Yes, please.

I'll crack a beer and cheer on it tonight. Good times :)

Javier