[PATCH RFC 2/5] nvme: add sysfs attribute to change admin timeout per nvme controller

[Heyne, Maximilian]

On Thu, Feb 12, 2026 at 01:09:48PM +0100, Maurizio Lombardi wrote:
> Currently, there is no method to adjust the timeout values
> on a per controller basis with nvme admin queues.
> Add an admin_timeout attribute to nvme so that different
> nvme controllers which may have different timeout
> requirements can have custom admin timeouts set.
> 
> Signed-off-by: Maurizio Lombardi <mlombard at redhat.com>

What would it take to have a "queue" directory representing the
admin_queue for an nvme controller like we have "queue" for the io
queues of the namespaces? This way we could change/inspect more than
just the admin_timeout for the admin queue. Or does this not make any
sense?

> ---
>  drivers/nvme/host/sysfs.c | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
> 
> diff --git a/drivers/nvme/host/sysfs.c b/drivers/nvme/host/sysfs.c
> index 29430949ce2f..149cd1ab3b3d 100644
> --- a/drivers/nvme/host/sysfs.c
> +++ b/drivers/nvme/host/sysfs.c
> @@ -601,6 +601,36 @@ static ssize_t dctype_show(struct device *dev,
>  }
>  static DEVICE_ATTR_RO(dctype);
>  
> +static ssize_t nvme_admin_timeout_show(struct device *dev,
> +			struct device_attribute *attr, char *buf)
> +{
> +	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
> +
> +	return sysfs_emit(buf, "%u\n",
> +				jiffies_to_msecs(ctrl->admin_q->rq_timeout));
> +}
> +
> +static ssize_t nvme_admin_timeout_store(struct device *dev,
> +			struct device_attribute *attr,
> +			const char *buf, size_t count)
> +{
> +	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
> +	u32 timeout;
> +	int err;
> +
> +	err = kstrtou32(buf, 10, &timeout);
> +	if (err || !timeout)
> +		return -EINVAL;
> +
> +	blk_queue_rq_timeout(ctrl->admin_q, msecs_to_jiffies(timeout));
> +
> +	return count;
> +}
> +
> +static struct device_attribute dev_attr_admin_timeout =  \
> +	__ATTR(admin_timeout, S_IRUGO | S_IWUSR, \
> +	nvme_admin_timeout_show, nvme_admin_timeout_store);

Why not

  DEVICE_ATTR(admin_timeout, S_IRUGO | S_IWUSR, nvme_admin_timeout_show
  nvme_admin_timeout_store);

?

> +
>  #ifdef CONFIG_NVME_HOST_AUTH
>  static ssize_t nvme_ctrl_dhchap_secret_show(struct device *dev,
>  		struct device_attribute *attr, char *buf)
> @@ -742,6 +772,7 @@ static struct attribute *nvme_dev_attrs[] = {
>  	&dev_attr_kato.attr,
>  	&dev_attr_cntrltype.attr,
>  	&dev_attr_dctype.attr,
> +	&dev_attr_admin_timeout.attr,
>  #ifdef CONFIG_NVME_HOST_AUTH
>  	&dev_attr_dhchap_secret.attr,
>  	&dev_attr_dhchap_ctrl_secret.attr,
> -- 
> 2.53.0
> 
> 



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