Re: [PATCH] PCI: Fix hotplug remove with sriov again

[Yinghai Lu <yinghai@kernel.org>]

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On Tue, Jul 23, 2013 at 7:04 PM, Yinghai Lu <yinghai@kernel.org> wrote:
> On Tue, Jul 23, 2013 at 7:01 PM, Yijing Wang <wangyijing@huawei.com> wrote:
>> Hi Yinghai,
>>    It seems to have the the same problem in acpiphp,
>>
>> diable_device(..):
>>
>>         while ((pdev = dev_in_slot(slot))) {
>>                 pci_stop_and_remove_bus_device(pdev);
>>                 pci_dev_put(pdev);
>>         }
>>
>>
>> static struct pci_dev *dev_in_slot(struct acpiphp_slot *slot)
>> {
>>         struct pci_bus *bus = slot->bridge->pci_bus;
>>         struct pci_dev *dev;
>>         struct pci_dev *ret = NULL;
>>
>>         down_read(&pci_bus_sem);
>>         list_for_each_entry(dev, &bus->devices, bus_list)
>>                 if (PCI_SLOT(dev->devfn) == slot->device) {
>>                         ret = pci_dev_get(dev);
>>                         break;
>>                 }
>>         up_read(&pci_bus_sem);
>>
>
> acpiphp is ok.
>
> dev_in_slot will restart from bus->devices again every time.

Actually I had another version to fix the problem, but I did not even
try to compile
and to test it after i figured out that mlx4_core like to VF get stopped before
PF's driver.

Thanks

Yinghai

[-- Attachment #2: fix_cx3_hotplug_1x.patch --]
[-- Type: application/octet-stream, Size: 1420 bytes --]

---
 drivers/pci/hotplug/pciehp_pci.c |   21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

Index: linux-2.6/drivers/pci/hotplug/pciehp_pci.c
===================================================================
--- linux-2.6.orig/drivers/pci/hotplug/pciehp_pci.c
+++ linux-2.6/drivers/pci/hotplug/pciehp_pci.c
@@ -76,12 +76,28 @@ int pciehp_configure_device(struct slot
 	return 0;
 }
 
+/* return one device on bus, acquiring a reference on it */
+static struct pci_dev *one_dev_on_bus(struct pci_bus *bus)
+{
+	struct pci_dev *dev;
+	struct pci_dev *ret = NULL;
+
+	down_read(&pci_bus_sem);
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		ret = pci_dev_get(dev);
+		break;
+	}
+	up_read(&pci_bus_sem);
+
+	return ret;
+}
+
 int pciehp_unconfigure_device(struct slot *p_slot)
 {
 	int ret, rc = 0;
 	u8 bctl = 0;
 	u8 presence = 0;
-	struct pci_dev *dev, *temp;
+	struct pci_dev *dev;
 	struct pci_bus *parent = p_slot->ctrl->pcie->port->subordinate;
 	u16 command;
 	struct controller *ctrl = p_slot->ctrl;
@@ -92,8 +108,7 @@ int pciehp_unconfigure_device(struct slo
 	if (ret)
 		presence = 0;
 
-	list_for_each_entry_safe(dev, temp, &parent->devices, bus_list) {
-		pci_dev_get(dev);
+	while (dev = one_dev_on_bus(parent)) {
 		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE && presence) {
 			pci_read_config_byte(dev, PCI_BRIDGE_CONTROL, &bctl);
 			if (bctl & PCI_BRIDGE_CTL_VGA) {