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Subject: Re: [PATCH 04/20] lightnvm: add minor version to generic geometry
To:     =?UTF-8?Q?Javier_Gonz=c3=a1lez?= <jg@lightnvm.io>
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-nvme@lists.infradead.org,
        =?UTF-8?Q?Javier_Gonz=c3=a1lez?= <javier@cnexlabs.com>
References: <1519205218-26994-1-git-send-email-javier@cnexlabs.com>
 <1519205218-26994-5-git-send-email-javier@cnexlabs.com>
From:   =?UTF-8?Q?Matias_Bj=c3=b8rling?= <mb@lightnvm.io>
Message-ID: <abd2b8f4-58b6-c97e-58e2-e271aae1f4a0@lightnvm.io>
Date:   Thu, 22 Feb 2018 08:34:57 +0100
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On 02/21/2018 10:26 AM, Javier González wrote:
> Separate the version between major and minor on the generic geometry.
> Also, add a "subversion" entry to sysfs to expose the minor version
> without breaking user space.
> 
> Signed-off-by: Javier González <javier@cnexlabs.com>
> ---
>   drivers/lightnvm/core.c      |  4 ++--
>   drivers/nvme/host/lightnvm.c | 25 ++++++++++++++++++++-----
>   include/linux/lightnvm.h     |  3 ++-
>   3 files changed, 24 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index 42596afdf64c..dc9ec6baff45 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -897,8 +897,8 @@ static int nvm_init(struct nvm_dev *dev)
>   		goto err;
>   	}
>   
> -	pr_debug("nvm: ver:%u nvm_vendor:%x\n",
> -				dev_geo->ver_id,
> +	pr_debug("nvm: ver:%u.%u nvm_vendor:%x\n",
> +				dev_geo->major_ver_id, dev_geo->minor_ver_id,
>   				dev_geo->c.vmnt);
>   
>   	ret = nvm_core_init(dev);
> diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c
> index 598abba66f52..71b4ac57a668 100644
> --- a/drivers/nvme/host/lightnvm.c
> +++ b/drivers/nvme/host/lightnvm.c
> @@ -296,7 +296,8 @@ static int nvme_nvm_setup_12(struct nvme_nvm_id12 *id,
>   	}
>   
>   	/* 1.2 spec. only reports a single version id - unfold */
> -	dev_geo->ver_id = id->ver_id;
> +	dev_geo->major_ver_id = id->ver_id;
> +	dev_geo->minor_ver_id = 2;
>   
>   	dev_geo->nr_chnls = src->num_ch;
>   	dev_geo->nr_luns = src->num_lun;
> @@ -377,7 +378,14 @@ static void nvme_nvm_set_addr_20(struct nvm_addr_format *dst,
>   static int nvme_nvm_setup_20(struct nvme_nvm_id20 *id,
>   			     struct nvm_dev_geo *dev_geo)
>   {
> -	dev_geo->ver_id = id->mjr;
> +	dev_geo->major_ver_id = id->mjr;
> +	dev_geo->minor_ver_id = id->mnr;
> +
> +	if (!(dev_geo->major_ver_id == 2 && dev_geo->minor_ver_id == 0)) {
> +		pr_err("nvm: OCSSD version not supported (v%d.%d)\n",
> +				dev_geo->major_ver_id, dev_geo->minor_ver_id);
> +		return -EINVAL;
> +	}
>   
>   	dev_geo->nr_chnls = le16_to_cpu(id->num_grp);
>   	dev_geo->nr_luns = le16_to_cpu(id->num_pu);
> @@ -913,7 +921,11 @@ static ssize_t nvm_dev_attr_show(struct device *dev,
>   	attr = &dattr->attr;
>   
>   	if (strcmp(attr->name, "version") == 0) {
> -		return scnprintf(page, PAGE_SIZE, "%u\n", dev_geo->ver_id);
> +		return scnprintf(page, PAGE_SIZE, "%u\n",
> +						dev_geo->major_ver_id);
> +	} else if (strcmp(attr->name, "subversion") == 0) {
> +		return scnprintf(page, PAGE_SIZE, "%u\n",
> +						dev_geo->minor_ver_id);
>   	} else if (strcmp(attr->name, "media_capabilities") == 0) {
>   		return scnprintf(page, PAGE_SIZE, "%u\n", dev_geo->c.mccap);
>   	} else if (strcmp(attr->name, "read_typ") == 0) {
> @@ -1055,6 +1067,7 @@ static ssize_t nvm_dev_attr_show_20(struct device *dev,
>   
>   /* general attributes */
>   static NVM_DEV_ATTR_RO(version);
> +static NVM_DEV_ATTR_RO(subversion);
>   static NVM_DEV_ATTR_RO(media_capabilities);
>   
>   static NVM_DEV_ATTR_RO(read_typ);
> @@ -1085,6 +1098,7 @@ static NVM_DEV_ATTR_12_RO(max_phys_secs);
>   
>   static struct attribute *nvm_dev_attrs_12[] = {
>   	&dev_attr_version.attr,
> +	&dev_attr_subversion.attr,
>   	&dev_attr_media_capabilities.attr,
>   
>   	&dev_attr_vendor_opcode.attr,
> @@ -1134,6 +1148,7 @@ static NVM_DEV_ATTR_20_RO(reset_max);
>   
>   static struct attribute *nvm_dev_attrs_20[] = {
>   	&dev_attr_version.attr,
> +	&dev_attr_subversion.attr,
>   	&dev_attr_media_capabilities.attr,
>   
>   	&dev_attr_groups.attr,
> @@ -1167,7 +1182,7 @@ int nvme_nvm_register_sysfs(struct nvme_ns *ns)
>   	if (!ndev)
>   		return -EINVAL;
>   
> -	switch (dev_geo->ver_id) {
> +	switch (dev_geo->major_ver_id) {
>   	case 1:
>   		return sysfs_create_group(&disk_to_dev(ns->disk)->kobj,
>   					&nvm_dev_attr_group_12);
> @@ -1184,7 +1199,7 @@ void nvme_nvm_unregister_sysfs(struct nvme_ns *ns)
>   	struct nvm_dev *ndev = ns->ndev;
>   	struct nvm_dev_geo *dev_geo = &ndev->dev_geo;
>   
> -	switch (dev_geo->ver_id) {
> +	switch (dev_geo->major_ver_id) {
>   	case 1:
>   		sysfs_remove_group(&disk_to_dev(ns->disk)->kobj,
>   					&nvm_dev_attr_group_12);
> diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
> index 18e3751b1632..5af0b8837095 100644
> --- a/include/linux/lightnvm.h
> +++ b/include/linux/lightnvm.h
> @@ -242,7 +242,8 @@ struct nvm_common_geo {
>   /* Device identified geometry */
>   struct nvm_dev_geo {
>   	/* device reported version */
> -	u8	ver_id;
> +	u8	major_ver_id;
> +	u8	minor_ver_id;
>   
>   	/* full device geometry */
>   	u16	nr_chnls;
> 

Looks fairly good to me. Did you consider putting in the major and minor 
version id into the version attribute? e.g., keep 1 as 1, and have 
version 2 be exposed as 2.0?