[RFC v1] nvme: add cse, ds, ms, nsze and nuse to sysfs
Christoph Hellwig
hch at lst.de
Mon Nov 27 06:18:57 PST 2023
On Mon, Nov 27, 2023 at 11:32:08AM +0100, Daniel Wagner wrote:
> Also getting a pointer to the nvme_ns data structure is a bit strange
> (dev_to_nvme_ns).
> This stip is necessary as many of the ns attributes are in
> nvme_ns. Shouldn't these per path values not all be the same and thus couldn't
> these be in nvme_ns_head? Anyway, just not sure who to deal with this. So any
> pointers highly welcomed!
Yes, they probably should be in the ns_head.
> + list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
> + down_read(&ctrl->namespaces_rwsem);
> + list_for_each_entry(ns, &ctrl->namespaces, list) {
> + ret = ns;
> + break;
> + }
> + up_read(&ctrl->namespaces_rwsem);
> + }
> + return ret;
> + }
.. I also don't think this would even be safe as-is as we dont hold
a reference to the ns after dropping the lock.
> +static ssize_t csi_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + return sysfs_emit(buf, "%d\n", dev_to_ns_head(dev)->ids.csi);
> +}
> +static DEVICE_ATTR_RO(csi);
> +
> +static ssize_t lba_ds_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + struct nvme_ns *ns = dev_to_nvme_ns(dev);
> +
> + return sysfs_emit(buf, "%d\n", ns->lba_shift);
lba_ds is a bit of an odd name. And I also don't think we even need
this, because it really is just a weird enconding for the logical block
size already exposed by the block layer.
> +static ssize_t lba_ms_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + struct nvme_ns *ns = dev_to_nvme_ns(dev);
> +
> + return sysfs_emit(buf, "%d\n", ns->ms);
> +}
> +static DEVICE_ATTR_RO(lba_ms);
I'd probably spell out metadata_size, or probably even better
metadata_bytes to match the unit postfixes elsewhere in the block code.
> +
> +static ssize_t nsze_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + struct nvme_ns *ns = dev_to_nvme_ns(dev);
> +
> + return sysfs_emit(buf, "%llu\n", ns->nsze);
> +}
> +static DEVICE_ATTR_RO(nsze);
This is just the normal size of the block device we already export.
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