diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index c0253de74945..f9ae5ad284ff 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -1534,9 +1534,24 @@ static const struct attribute_group *region_groups[] = { static void cxl_region_release(struct device *dev) { + struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev->parent); struct cxl_region *cxlr = to_cxl_region(dev); + int id = atomic_read(&cxlrd->region_id); + + /* + * Try to reuse the recently idled id rather than the cached + * next id to prevent the region id space from increasing + * unnecessarily. + */ + if (cxlr->id < id) + if (atomic_try_cmpxchg(&cxlrd->region_id, &id, cxlr->id)) { + memregion_free(id); + goto out; + } memregion_free(cxlr->id); +out: + put_device(dev->parent); kfree(cxlr); } @@ -1598,6 +1613,11 @@ static struct cxl_region *cxl_region_alloc(struct cxl_root_decoder *cxlrd, int i device_initialize(dev); lockdep_set_class(&dev->mutex, &cxl_region_key); dev->parent = &cxlrd->cxlsd.cxld.dev; + /* + * Keep root decoder pinned through cxl_region_release to fixup + * region id allocations + */ + get_device(dev->parent); device_set_pm_not_required(dev); dev->bus = &cxl_bus_type; dev->type = &cxl_region_type;