Re: [PATCH v2 01/19] PCI/TSM: Report active IDE streams per host bridge

[Jonathan Cameron <jonathan.cameron@huawei.com>]

On Mon,  2 Mar 2026 16:01:49 -0800
Dan Williams <dan.j.williams@intel.com> wrote:

> The first attempt at an ABI for this failed to account for naming
> collisions across host bridges:
> 
> Commit a4438f06b1db ("PCI/TSM: Report active IDE streams")
> 
> Revive this ABI with a per host bridge link that appears at first stream
> creation for a given host bridge and disappears after the last stream is
> removed.
> 
> For systems with many host bridge objects it allows:
> 
>     ls /sys/class/tsm/tsmN/pci*/stream*
> 
> ...to find all the host bridges with active streams without first iterating
> over all host bridges. Yilun notes that is handy to have this short cut [1]
> and from an administrator perspective it helps with inventory for
> constrained stream resources.
> 
> Link: http://lore.kernel.org/aXLtILY85oMU5qlb@yilunxu-OptiPlex-7050 [1]
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

> diff --git a/drivers/virt/coco/tsm-core.c b/drivers/virt/coco/tsm-core.c
> index 8712df8596a1..3c99c38cfaa5 100644
> --- a/drivers/virt/coco/tsm-core.c
> +++ b/drivers/virt/coco/tsm-core.c
> @@ -4,10 +4,12 @@

> +
> +static struct tsm_ide_stream *create_streams(struct tsm_dev *tsm_dev,
> +					    struct pci_host_bridge *bridge)
> +{
> +	int rc;
> +
> +	struct tsm_ide_stream *streams __free(kfree) =
> +		kzalloc(sizeof(*streams), GFP_KERNEL);

Crossed with kzalloc_obj() etc being introduced which seems appropriate here.
 
> +	if (!streams)
> +		return NULL;
> +
> +	streams->tsm_dev = tsm_dev;
> +	streams->bridge = bridge;
> +	kref_init(&streams->kref);
> +	rc = xa_insert(&tsm_ide_streams, (unsigned long)bridge, streams,
> +		       GFP_KERNEL);
> +	if (rc)
> +		return NULL;
> +
> +	rc = sysfs_create_link(&tsm_dev->dev.kobj, &bridge->dev.kobj,
> +			       dev_name(&bridge->dev));
> +	if (rc) {
> +		xa_erase(&tsm_ide_streams, (unsigned long)bridge);
> +		return NULL;
> +	}
> +
> +	return no_free_ptr(streams);
> +}