On Wed, Apr 19, 2023 at 07:40:35PM -0700, Dexuan Cui wrote:
This reverts commit d6af2ed29c7c1c311b96dac989dcb991e90ee195.
The statement "the hv_pci_bus_exit() call releases structures of all its child devices" in commit d6af2ed29c7c is not true: in the path hv_pci_probe() -> hv_pci_enter_d0() -> hv_pci_bus_exit(hdev, true): the parameter "keep_devs" is true, so hv_pci_bus_exit() does *not* release the child "struct hv_pci_dev *hpdev" that is created earlier in pci_devices_present_work() -> new_pcichild_device().
The commit d6af2ed29c7c was originally made in July 2020 for RHEL 7.7, where the old version of hv_pci_bus_exit() was used; when the commit was rebased and merged into the upstream, people didn't notice that it's not really necessary. The commit itself doesn't cause any issue, but it makes hv_pci_probe() more complicated. Revert it to facilitate some upcoming changes to hv_pci_probe().
If d6af2ed29c7c does not cause any issue this is not a fix and should be merged only with subsequent changes.
Signed-off-by: Dexuan Cui decui@microsoft.com Reviewed-by: Michael Kelley mikelley@microsoft.com Acked-by: Wei Hu weh@microsoft.com Cc: stable@vger.kernel.org
v2: No change to the patch body. Added Wei Hu's Acked-by. Added Cc:stable
v3: Added Michael's Reviewed-by.
drivers/pci/controller/pci-hyperv.c | 71 ++++++++++++++--------------- 1 file changed, 34 insertions(+), 37 deletions(-)
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index 46df6d093d683..48feab095a144 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -3225,8 +3225,10 @@ static int hv_pci_enter_d0(struct hv_device *hdev) struct pci_bus_d0_entry *d0_entry; struct hv_pci_compl comp_pkt; struct pci_packet *pkt;
- bool retry = true; int ret;
+enter_d0_retry: /* * Tell the host that the bus is ready to use, and moved into the * powered-on state. This includes telling the host which region @@ -3253,6 +3255,38 @@ static int hv_pci_enter_d0(struct hv_device *hdev) if (ret) goto exit;
- /*
* In certain case (Kdump) the pci device of interest was* not cleanly shut down and resource is still held on host* side, the host could return invalid device status.* We need to explicitly request host to release the resource* and try to enter D0 again.*/- if (comp_pkt.completion_status < 0 && retry) {
retry = false;dev_err(&hdev->device, "Retrying D0 Entry\n");/** Hv_pci_bus_exit() calls hv_send_resource_released()* to free up resources of its child devices.* In the kdump kernel we need to set the* wslot_res_allocated to 255 so it scans all child* devices to release resources allocated in the* normal kernel before panic happened.*/hbus->wslot_res_allocated = 255;ret = hv_pci_bus_exit(hdev, true);if (ret == 0) {kfree(pkt);goto enter_d0_retry;}dev_err(&hdev->device,"Retrying D0 failed with ret %d\n", ret);- }
- if (comp_pkt.completion_status < 0) { dev_err(&hdev->device, "PCI Pass-through VSP failed D0 Entry with status %x\n",
@@ -3493,7 +3527,6 @@ static int hv_pci_probe(struct hv_device *hdev, struct hv_pcibus_device *hbus; u16 dom_req, dom; char *name;
- bool enter_d0_retry = true; int ret;
/* @@ -3633,47 +3666,11 @@ static int hv_pci_probe(struct hv_device *hdev, if (ret) goto free_fwnode; -retry: ret = hv_pci_query_relations(hdev); if (ret) goto free_irq_domain; ret = hv_pci_enter_d0(hdev);
- /*
* In certain case (Kdump) the pci device of interest was* not cleanly shut down and resource is still held on host* side, the host could return invalid device status.* We need to explicitly request host to release the resource* and try to enter D0 again.* Since the hv_pci_bus_exit() call releases structures* of all its child devices, we need to start the retry from* hv_pci_query_relations() call, requesting host to send* the synchronous child device relations message before this* information is needed in hv_send_resources_allocated()* call later.*/- if (ret == -EPROTO && enter_d0_retry) {
enter_d0_retry = false;dev_err(&hdev->device, "Retrying D0 Entry\n");/** Hv_pci_bus_exit() calls hv_send_resources_released()* to free up resources of its child devices.* In the kdump kernel we need to set the* wslot_res_allocated to 255 so it scans all child* devices to release resources allocated in the* normal kernel before panic happened.*/hbus->wslot_res_allocated = 255;ret = hv_pci_bus_exit(hdev, true);if (ret == 0)goto retry;dev_err(&hdev->device,"Retrying D0 failed with ret %d\n", ret);- } if (ret) goto free_irq_domain;
2.25.1