[PATCH v6 1/2] PCI: endpoint: pci-epf-vntb: Serialize virtual PCI bus scan

[Koichiro Den <den@valinux.co.jp>]

The virtual PCI bus is scanned without holding the PCI rescan/remove
lock. This can race with other PCI topology changes.

Hold the lock across the bus scan and device addition.

Fixes: e35f56bb0330 ("PCI: endpoint: Support NTB transfer between RC and EP")
Suggested-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://lore.kernel.org/r/3tgrcel5fl55ulf3zjya4fkz4t2ms7iwwjif5rnzn2rafsydd6@i4e5etm7uqvz/
Signed-off-by: Koichiro Den <den@valinux.co.jp>
---
Changes in v6:
  - New patch based on Mani's review of v5 patch 4.

 drivers/pci/endpoint/functions/pci-epf-vntb.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c
index c3caec927d74..412e8cc6fb1d 100644
--- a/drivers/pci/endpoint/functions/pci-epf-vntb.c
+++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
@@ -1332,14 +1332,19 @@ static int vpci_scan_bus(void *sysdata)
 	struct pci_bus *vpci_bus;
 	struct epf_ntb *ndev = sysdata;
 
+	pci_lock_rescan_remove();
+
 	vpci_bus = pci_scan_bus(ndev->vbus_number, &vpci_ops, sysdata);
 	if (!vpci_bus) {
 		pr_err("create pci bus failed\n");
+		pci_unlock_rescan_remove();
 		return -EINVAL;
 	}
 
 	pci_bus_add_devices(vpci_bus);
 
+	pci_unlock_rescan_remove();
+
 	return 0;
 }
 
-- 
2.51.0