[PATCH] nvme: Support user mode processing of ZNS Zone Changed AEN

[Sagi Grimberg]

> The ZNS Zone-Descriptor-Changes AEN is of type notify and uses CQE.DW1
> to convey the namespace of the log page to read. Unhandled notify AENs
> now generate an NVME_AEN uevent and include the value of CQE.DW1 as a
> new property when non-zero.

But you always send it...

> 
> All unhandled notify events are include to avoid command set specific
> code in the aen handling.  This support is planned to be used by both
> zone based applications and another unreleased device with an alternate
> command set.

This needs to be split into two patches.

> 
> Signed-off-by: Clay Mayers <clay.mayers at kioxia.com>
> ---
>   drivers/nvme/host/core.c | 19 +++++++++++--------
>   drivers/nvme/host/nvme.h |  1 +
>   2 files changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 66446f1e06cf..fa865b8da1d3 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -4615,17 +4615,20 @@ static void nvme_change_uevent(struct nvme_ctrl *ctrl, char *envdata)
>   
>   static void nvme_aen_uevent(struct nvme_ctrl *ctrl)
>   {
> -	char *envp[2] = { NULL, NULL };
> +	char *envp[3] = { NULL, NULL, NULL };
>   	u32 aen_result = ctrl->aen_result;
> +	u32 aen_data = ctrl->aen_data;
>   
>   	ctrl->aen_result = 0;
> +	ctrl->aen_data = 0;
>   	if (!aen_result)
>   		return;
>   
>   	envp[0] = kasprintf(GFP_KERNEL, "NVME_AEN=%#08x", aen_result);
> -	if (!envp[0])
> -		return;
> -	kobject_uevent_env(&ctrl->device->kobj, KOBJ_CHANGE, envp);
> +	envp[1] = kasprintf(GFP_KERNEL, "NVME_AEN_DATA=%#08x", aen_data);
> +	if (envp[0] && envp[1])
> +		kobject_uevent_env(&ctrl->device->kobj, KOBJ_CHANGE, envp);
> +	kfree(envp[1]);
>   	kfree(envp[0]);
>   }
>   
> @@ -4748,11 +4751,9 @@ static bool nvme_handle_aen_notice(struct nvme_ctrl *ctrl, u32 result)
>   		queue_work(nvme_wq, &ctrl->ana_work);
>   		break;
>   #endif
> -	case NVME_AER_NOTICE_DISC_CHANGED:
> +	default:
>   		ctrl->aen_result = result;
>   		break;
> -	default:
> -		dev_warn(ctrl->device, "async event result %08x\n", result);

I'd keep the log... and also don't know if we want to pass any unknown
possible spam to userspace... not sure that being blindly forward
compatible is the right choice here.

>   	}
>   	return requeue;
>   }
> @@ -4799,8 +4800,10 @@ void nvme_complete_async_event(struct nvme_ctrl *ctrl, __le16 status,
>   		break;
>   	}
>   
> -	if (requeue)
> +	if (requeue) {
> +		ctrl->aen_data = le64_to_cpu(res->u64) >> 32;

Please use a helper for that.
aen_data is not a great name... maybe use a union for that for the
specific aen subtype?

Maybe it'd be better that zoned namespace aen is handled explicitly
and passes a AEN_NSID env veriable to the uevent.

>   		queue_work(nvme_wq, &ctrl->async_event_work);
> +	}
>   }
>   EXPORT_SYMBOL_GPL(nvme_complete_async_event);
>   
> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
> index 1bdf714dcd9e..a1bab447dc65 100644
> --- a/drivers/nvme/host/nvme.h
> +++ b/drivers/nvme/host/nvme.h
> @@ -299,6 +299,7 @@ struct nvme_ctrl {
>   	u16 cctemp;
>   	u32 oaes;
>   	u32 aen_result;
> +	u32 aen_data;
>   	u32 ctratt;
>   	unsigned int shutdown_timeout;
>   	unsigned int kato;