[PATCH 6/6] PCI: hv: Use async probing to reduce boot time
From: Dexuan Cui <decui@microsoft.com>
Date: 2023-03-28 04:54:24
Also in:
linux-hyperv, linux-pci, linux-rdma, lkml
Subsystem:
hyper-v/azure core and drivers, pci native host bridge and endpoint drivers, pci subsystem, the rest · Maintainers:
"K. Y. Srinivasan", Haiyang Zhang, Wei Liu, Dexuan Cui, Long Li, Lorenzo Pieralisi, Krzysztof Wilczyński, Manivannan Sadhasivam, Bjorn Helgaas, Linus Torvalds
Commit 414428c5da1c ("PCI: hv: Lock PCI bus on device eject") added the
pci_lock_rescan_remove() and pci_unlock_rescan_remove() to address the
race between create_root_hv_pci_bus() and hv_eject_device_work(), but it
doesn't really work well.
Now with hbus->state_lock and other fixes, the race is resolved, so
remove pci_{lock,unlock}_rescan_remove().
Also enable async probing to reduce boot time.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
drivers/pci/controller/pci-hyperv.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 2c0b86b20408..08ab389e27cc 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c@@ -2312,12 +2312,16 @@ static int create_root_hv_pci_bus(struct hv_pcibus_device *hbus) if (error) return error; - pci_lock_rescan_remove(); + /* + * pci_lock_rescan_remove() and pci_unlock_rescan_remove() are + * unnecessary here, because we hold the hbus->state_lock, meaning + * hv_eject_device_work() and pci_devices_present_work() can't race + * with create_root_hv_pci_bus(). + */ hv_pci_assign_numa_node(hbus); pci_bus_assign_resources(bridge->bus); hv_pci_assign_slots(hbus); pci_bus_add_devices(bridge->bus); - pci_unlock_rescan_remove(); hbus->state = hv_pcibus_installed; return 0; }
@@ -4003,6 +4007,9 @@ static struct hv_driver hv_pci_drv = { .remove = hv_pci_remove, .suspend = hv_pci_suspend, .resume = hv_pci_resume, + .driver = { + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, }; static void __exit exit_hv_pci_drv(void)
--
2.25.1