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SubjectRe: [PATCH v7 11/14] nvmet-configfs: introduce passthru configfs interface
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On 8/2/2019 2:45 AM, Logan Gunthorpe wrote:
> When CONFIG_NVME_TARGET_PASSTHRU as 'passthru' directory will
> be added to each subsystem. The directory is similar to a namespace
> and has two attributes: device_path and enable. The user must set the
> path to the nvme controller's char device and write '1' to enable the
> subsystem to use passthru.
>
> Any given subsystem is prevented from enabling both a regular namespace
> and the passthru device. If one is enabled, enabling the other will
> produce an error.
>
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> ---
> drivers/nvme/target/configfs.c | 99 ++++++++++++++++++++++++++++++++++
> drivers/nvme/target/nvmet.h | 1 +
> 2 files changed, 100 insertions(+)
>
> diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
> index 98613a45bd3b..b15d64c19f58 100644
> --- a/drivers/nvme/target/configfs.c
> +++ b/drivers/nvme/target/configfs.c
> @@ -615,6 +615,103 @@ static const struct config_item_type nvmet_namespaces_type = {
> .ct_owner = THIS_MODULE,
> };
>
> +#ifdef CONFIG_NVME_TARGET_PASSTHRU
> +
> +static ssize_t nvmet_passthru_device_path_show(struct config_item *item,
> + char *page)
> +{
> + struct nvmet_subsys *subsys = to_subsys(item->ci_parent);
> +
> + return snprintf(page, PAGE_SIZE, "%s\n", subsys->passthru_ctrl_path);
> +}
> +
> +static ssize_t nvmet_passthru_device_path_store(struct config_item *item,
> + const char *page, size_t count)
> +{
> + struct nvmet_subsys *subsys = to_subsys(item->ci_parent);
> + int ret = -ENOMEM;

seems like a redundant initialization.

> + size_t len;
> +
> + mutex_lock(&subsys->lock);
> +
> + ret = -EBUSY;
> + if (subsys->passthru_ctrl)
> + goto out_unlock;
> +
> + ret = -EINVAL;
> + len = strcspn(page, "\n");
> + if (!len)
> + goto out_unlock;
> +
> + kfree(subsys->passthru_ctrl_path);
> + ret = -ENOMEM;
> + subsys->passthru_ctrl_path = kstrndup(page, len, GFP_KERNEL);
> + if (!subsys->passthru_ctrl_path)
> + goto out_unlock;
> +
> + mutex_unlock(&subsys->lock);
> +
> + return count;
> +out_unlock:
> + mutex_unlock(&subsys->lock);
> + return ret;
> +}
> +CONFIGFS_ATTR(nvmet_passthru_, device_path);
> +
> +static ssize_t nvmet_passthru_enable_show(struct config_item *item,
> + char *page)
> +{
> + struct nvmet_subsys *subsys = to_subsys(item->ci_parent);
> +
> + return sprintf(page, "%d\n", subsys->passthru_ctrl ? 1 : 0);
> +}
> +
> +static ssize_t nvmet_passthru_enable_store(struct config_item *item,
> + const char *page, size_t count)
> +{
> + struct nvmet_subsys *subsys = to_subsys(item->ci_parent);
> + bool enable;
> + int ret = 0;
> +
> + if (strtobool(page, &enable))
> + return -EINVAL;
> +
> + if (enable)
> + ret = nvmet_passthru_ctrl_enable(subsys);
> + else
> + nvmet_passthru_ctrl_disable(subsys);
> +
> + return ret ? ret : count;
> +}
> +CONFIGFS_ATTR(nvmet_passthru_, enable);
> +
> +static struct configfs_attribute *nvmet_passthru_attrs[] = {
> + &nvmet_passthru_attr_device_path,
> + &nvmet_passthru_attr_enable,
> + NULL,
> +};
> +
> +static const struct config_item_type nvmet_passthru_type = {
> + .ct_attrs = nvmet_passthru_attrs,
> + .ct_owner = THIS_MODULE,
> +};
> +
> +static void nvmet_add_passthru_group(struct nvmet_subsys *subsys)
> +{
> + config_group_init_type_name(&subsys->passthru_group,
> + "passthru", &nvmet_passthru_type);
> + configfs_add_default_group(&subsys->passthru_group,
> + &subsys->group);
> +}
> +
> +#else /* CONFIG_NVME_TARGET_PASSTHRU */
> +
> +static void nvmet_add_passthru_group(struct nvmet_subsys *subsys)
> +{
> +}
> +
> +#endif /* CONFIG_NVME_TARGET_PASSTHRU */
> +
> static int nvmet_port_subsys_allow_link(struct config_item *parent,
> struct config_item *target)
> {
> @@ -915,6 +1012,8 @@ static struct config_group *nvmet_subsys_make(struct config_group *group,
> configfs_add_default_group(&subsys->allowed_hosts_group,
> &subsys->group);
>
> + nvmet_add_passthru_group(subsys);
> +
> return &subsys->group;
> }
>
> diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
> index 6436cb990905..f9c593f1305d 100644
> --- a/drivers/nvme/target/nvmet.h
> +++ b/drivers/nvme/target/nvmet.h
> @@ -231,6 +231,7 @@ struct nvmet_subsys {
> #ifdef CONFIG_NVME_TARGET_PASSTHRU
> struct nvme_ctrl *passthru_ctrl;
> char *passthru_ctrl_path;
> + struct config_group passthru_group;
> #endif /* CONFIG_NVME_TARGET_PASSTHRU */
> };
>

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