Re: [PATCH v8 8/9] PCI/IDE: Report available IDE streams

Xu Yilun
2025-11-10T05:03:47Z

On Fri, Oct 31, 2025 at 02:29:00PM -0700, Dan Williams wrote:
> The limited number of link-encryption (IDE) streams that a given set of
> host bridges supports is a platform specific detail. Provide
> pci_ide_init_nr_streams() as a generic facility for either platform TSM

Should be updated to pci_ide_set_nr_streams().

> drivers, or PCI core native IDE, to report the number available streams.
> After invoking pci_ide_init_nr_streams() an "available_secure_streams"

I suppose should also be pci_ide_set_nr_streams() here.

> attribute appears in PCI host bridge sysfs to convey that count.

I don't see how it appears later.

> +static umode_t pci_ide_attr_visible(struct kobject *kobj, struct attribute *a, int n)
> +{
> + struct device *dev = kobj_to_dev(kobj);
> + struct pci_host_bridge *hb = to_pci_host_bridge(dev);
> +
> + if (a == &dev_attr_available_secure_streams.attr)
> + if (!hb->nr_ide_streams)
> + return 0;

The previous patch unconditionally initializes nr_ide_streams to 256, so
this check is not functional for "appear later". Maybe remove it.

> +
> + return a->mode;
> +}
> +
> +const struct attribute_group pci_ide_attr_group = {
> + .attrs = pci_ide_attrs,
> + .is_visible = pci_ide_attr_visible,
> +};
> +
> +/**
> + * pci_ide_set_nr_streams() - sets size of the pool of IDE Stream resources
> + * @hb: host bridge boundary for the stream pool
> + * @nr: number of streams
> + *
> + * Platform PCI init and/or expert test module use only. Limit IDE
> + * Stream establishment by setting the number of stream resources
> + * available at the host bridge. Platform init code must set this before
> + * the first pci_ide_stream_alloc() call if the platform has less than the
> + * default of 256 streams per host-bridge.
> + *
> + * The "PCI_IDE" symbol namespace is required because this is typically
> + * a detail that is settled in early PCI init. I.e. this export is not
> + * for endpoint drivers.
> + */
> +void pci_ide_set_nr_streams(struct pci_host_bridge *hb, u16 nr)
> +{
> + hb->nr_ide_streams = min(nr, 256);
> + WARN_ON_ONCE(!ida_is_empty(&hb->ide_stream_ida));
> + sysfs_update_group(&hb->dev.kobj, &pci_ide_attr_group);

Also no need to update group, is it?

Should be easy to address these concerns. I believe I can also:

Reviewed-by: Xu Yilun <yilun.xu@linux.intel.com>

> +}