Re: [PATCH RFC v2] nvme: basic RMEDIA support for host

[Damien Le Moal <dlemoal@kernel.org>]

On 7/24/24 21:30, Wang Yugui wrote:
> Rotational media(RMEDIA) support is added to the NVMe 2.0 specification.
> We firstly add Rotational media(RMEDIA) support to nvme host, then we can add
> the support to nvme target later if the backstore is a Rotational media(RMEDIA)
> block device.

Why not do that now in another patch, at least for the loop target ? Given that
they are not that many NVMe-HDD out there, that would be nice to have to test this.

> 
> Signed-off-by: Wang Yugui <wangyugui@e16-tech.com>
> ---
>  drivers/nvme/host/core.c      | 5 +++++
>  drivers/nvme/host/multipath.c | 3 +++
>  drivers/nvme/host/nvme.h      | 1 +
>  include/linux/nvme.h          | 1 +
>  4 files changed, 10 insertions(+)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 19917253ba7b..f4c41bf70b19 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -40,6 +40,7 @@ struct nvme_ns_info {
>  	bool is_readonly;
>  	bool is_ready;
>  	bool is_removed;
> +	bool is_rmedia;
>  };
>  
>  unsigned int admin_timeout = 60;
> @@ -1622,6 +1623,7 @@ static int nvme_ns_info_from_id_cs_indep(struct nvme_ctrl *ctrl,
>  		info->is_shared = id->nmic & NVME_NS_NMIC_SHARED;
>  		info->is_readonly = id->nsattr & NVME_NS_ATTR_RO;
>  		info->is_ready = id->nstat & NVME_NSTAT_NRDY;
> +		info->is_rmedia = id->nsfeat & NVME_INDEP_NS_FEAT_RMEDIA;
>  	}
>  	kfree(id);
>  	return ret;
> @@ -3613,6 +3618,7 @@ static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
>  	head->ns_id = info->nsid;
>  	head->ids = info->ids;
>  	head->shared = info->is_shared;
> +	head->rmedia = info->is_rmedia;
>  	ratelimit_state_init(&head->rs_nuse, 5 * HZ, 1);
>  	ratelimit_set_flags(&head->rs_nuse, RATELIMIT_MSG_ON_RELEASE);
>  	kref_init(&head->ref);
> @@ -3816,6 +3816,8 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, struct nvme_ns_info *info)
>  
>  	if (ctrl->opts && ctrl->opts->data_digest)
>  		lim.features |= BLK_FEAT_STABLE_WRITES;
> +	if (info->is_rmedia)
> +		lim.features |= BLK_FEAT_ROTATIONAL;
>  	if (ctrl->ops->supports_pci_p2pdma &&
>  	    ctrl->ops->supports_pci_p2pdma(ctrl))
>  		lim.features |= BLK_FEAT_PCI_P2PDMA;
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index 91d9eb3c22ef..a3cd6525d24d 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -626,6 +626,9 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
>  	head->disk->private_data = head;
>  	sprintf(head->disk->disk_name, "nvme%dn%d",
>  			ctrl->subsys->instance, head->instance);
> +
> +	if(head->rmedia)
> +		lim.features |= BLK_FEAT_ROTATIONAL;
>  	return 0;
>  }
>  
> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
> index f900e44243ae..9f2789c44249 100644
> --- a/drivers/nvme/host/nvme.h
> +++ b/drivers/nvme/host/nvme.h
> @@ -465,6 +465,7 @@ struct nvme_ns_head {
>  	struct list_head	entry;
>  	struct kref		ref;
>  	bool			shared;
> +	bool			rmedia;
>  	bool			passthru_err_log_enabled;
>  	int			instance;
>  	struct nvme_effects_log *effects;
> diff --git a/include/linux/nvme.h b/include/linux/nvme.h
> index c12a329dd463..2c259d126f80 100644
> --- a/include/linux/nvme.h
> +++ b/include/linux/nvme.h
> @@ -546,6 +546,7 @@ enum {
>  	NVME_NS_FEAT_THIN	= 1 << 0,
>  	NVME_NS_FEAT_ATOMICS	= 1 << 1,
>  	NVME_NS_FEAT_IO_OPT	= 1 << 4,
> +	NVME_INDEP_NS_FEAT_RMEDIA = 1 << 4,
>  	NVME_NS_ATTR_RO		= 1 << 0,
>  	NVME_NS_FLBAS_LBA_MASK	= 0xf,
>  	NVME_NS_FLBAS_LBA_UMASK	= 0x60,

-- 
Damien Le Moal
Western Digital Research