Re: [PATCH v3 7/7] PCI: endpoint: pci-epf-vntb: Manage ntb_dev lifetime and fix vpci bus teardown

On Mon, Dec 01, 2025 at 12:11:00AM +0900, Koichiro Den wrote:

Currently ntb_dev is embedded in epf_ntb, while configfs allows starting or stopping controller and linking or unlinking functions as you want. In fact, re-linking and re-starting is not possible with the embedded design and leads to oopses.

Allocate ntb_dev with devm and add a .remove callback to the pci driver that calls ntb_unregister_device(). This allows a fresh device to be created on the next .bind call.

With these changes, the controller can now be stopped, a function unlinked, configfs settings updated, and the controller re-linked and restarted without rebooting the endpoint, as long as the underlying pci_epc_ops .stop() operation is non-destructive, and .start() can restore normal operations.

Signed-off-by: Koichiro Den den@valinux.co.jp

drivers/pci/endpoint/functions/pci-epf-vntb.c | 52 ++++++++++++++----- 1 file changed, 39 insertions(+), 13 deletions(-)

...

@@ -1097,7 +1103,6 @@ static int vpci_scan_bus(void *sysdata) { struct pci_bus *vpci_bus; struct epf_ntb *ndev = sysdata;

Unneccsary change here.

Frank Li

LIST_HEAD(resources); static struct resource busn_res = { .start = 0, @@ -1115,6 +1120,7 @@ static int vpci_scan_bus(void *sysdata) pr_err("create pci bus failed\n"); return -EINVAL; }

• ndev->vpci_bus = vpci_bus;

  pci_bus_add_devices(vpci_bus);

@@ -1159,7 +1165,7 @@ static int vntb_epf_mw_set_trans(struct ntb_dev *ndev, int pidx, int idx, int ret; struct device *dev;

• dev = &ntb->ntb.dev;

• dev = &ntb->ntb->dev; barno = ntb->epf_ntb_bar[BAR_MW1 + idx]; epf_bar = &ntb->epf->bar[barno]; epf_bar->phys_addr = addr;

@@ -1259,7 +1265,7 @@ static int vntb_epf_peer_db_set(struct ntb_dev *ndev, u64 db_bits) ret = pci_epc_raise_irq(ntb->epf->epc, func_no, vfunc_no, PCI_IRQ_MSI, interrupt_num + 1); if (ret)

• dev_err(&ntb->ntb.dev, "Failed to raise IRQ\n");
  

• dev_err(&ntb->ntb->dev, "Failed to raise IRQ\n");
  
  

  return ret;

} @@ -1346,9 +1352,12 @@ static int pci_vntb_probe(struct pci_dev *pdev, const struct pci_device_id *id) struct epf_ntb *ndev = (struct epf_ntb *)pdev->sysdata; struct device *dev = &pdev->dev;

• ndev->ntb.pdev = pdev;
• ndev->ntb.topo = NTB_TOPO_NONE;
• ndev->ntb.ops = &vntb_epf_ops;

• ndev->ntb = devm_kzalloc(dev, sizeof(*ndev->ntb), GFP_KERNEL);

• if (!ndev->ntb)

• return -ENOMEM;
  

• ndev->ntb->pdev = pdev;

• ndev->ntb->topo = NTB_TOPO_NONE;

• ndev->ntb->ops = &vntb_epf_ops;

  ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32)); if (ret) {

@@ -1356,7 +1365,7 @@ static int pci_vntb_probe(struct pci_dev *pdev, const struct pci_device_id *id) return ret; }

• ret = ntb_register_device(&ndev->ntb);

• ret = ntb_register_device(ndev->ntb); if (ret) { dev_err(dev, "Failed to register NTB device\n"); return ret;

@@ -1366,6 +1375,17 @@ static int pci_vntb_probe(struct pci_dev *pdev, const struct pci_device_id *id) return 0; }

+static void pci_vntb_remove(struct pci_dev *pdev) +{

• struct epf_ntb *ndev = (struct epf_ntb *)pdev->sysdata;
• if (!ndev || !ndev->ntb)

• return;
  

• ntb_unregister_device(ndev->ntb);
• ndev->ntb = NULL;

+}

static struct pci_device_id pci_vntb_table[] = { { PCI_DEVICE(0xffff, 0xffff), @@ -1377,6 +1397,7 @@ static struct pci_driver vntb_pci_driver = { .name = "pci-vntb", .id_table = pci_vntb_table, .probe = pci_vntb_probe,

• .remove = pci_vntb_remove,

};

/* ============ PCIe EPF Driver Bind ====================*/ @@ -1459,10 +1480,15 @@ static void epf_ntb_unbind(struct pci_epf *epf) { struct epf_ntb *ntb = epf_get_drvdata(epf);

• pci_unregister_driver(&vntb_pci_driver);
• pci_lock_rescan_remove();
• pci_stop_root_bus(ntb->vpci_bus);
• pci_remove_root_bus(ntb->vpci_bus);
• pci_unlock_rescan_remove();
• epf_ntb_epc_cleanup(ntb); epf_ntb_config_spad_bar_free(ntb);

• pci_unregister_driver(&vntb_pci_driver);

}

// EPF driver probe

2.48.1