PCI: pciehp: Iterate over all devices in slot, not functions 0-7

Currently, we enumerate devices in a slot with pci_scan_slot(), then
iterate through all the devices we found by looking for functions 0-7.  But
that's wrong for ARI devices, which may have function numbers up to 255.

This means that when we hot-add an ARI device, pciehp only initializes
functions 0-7, and other functions don't work correctly.  Additionally, if
we hot-remove the device, pciehp only removes functions 0-7, leaving stale
pci_dev structures for any other functions.

This patch fixes the problem by iterating over devices in a slot by using
the upstream bridge's "bus->devices" list instead.

[bhelgaas: changelog]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 16 insertions, 28 deletions

diff --git a/drivers/pci/hotplug/pciehp_pci.c b/drivers/pci/hotplug/pciehp_pci.c
index 09cecaf450c5..aac7a40e4a4a 100644
--- a/drivers/pci/hotplug/pciehp_pci.c
+++ b/drivers/pci/hotplug/pciehp_pci.c
@@ -39,7 +39,7 @@ int pciehp_configure_device(struct slot *p_slot)
         struct pci_dev *dev;
         struct pci_dev *bridge = p_slot->ctrl->pcie->port;
         struct pci_bus *parent = bridge->subordinate;
-        int num, fn;
+        int num;
         struct controller *ctrl = p_slot->ctrl;
 
         dev = pci_get_slot(parent, PCI_DEVFN(0, 0));
@@ -57,28 +57,18 @@ int pciehp_configure_device(struct slot *p_slot)
                 return -ENODEV;
         }
 
-        for (fn = 0; fn < 8; fn++) {
-                dev = pci_get_slot(parent, PCI_DEVFN(0, fn));
-                if (!dev)
-                        continue;
+        list_for_each_entry(dev, &parent->devices, bus_list)
                 if ((dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) ||
                                 (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS))
                         pci_hp_add_bridge(dev);
-                pci_dev_put(dev);
-        }
 
         pci_assign_unassigned_bridge_resources(bridge);
 
-        for (fn = 0; fn < 8; fn++) {
-                dev = pci_get_slot(parent, PCI_DEVFN(0, fn));
-                if (!dev)
+        list_for_each_entry(dev, &parent->devices, bus_list) {
+                if ((dev->class >> 16) == PCI_BASE_CLASS_DISPLAY)
                         continue;
-                if ((dev->class >> 16) == PCI_BASE_CLASS_DISPLAY) {
-                        pci_dev_put(dev);
-                        continue;
-                }
+
                 pci_configure_slot(dev);
-                pci_dev_put(dev);
         }
 
         pci_bus_add_devices(parent);
@@ -89,9 +79,9 @@ int pciehp_configure_device(struct slot *p_slot)
 int pciehp_unconfigure_device(struct slot *p_slot)
 {
         int ret, rc = 0;
-        int j;
         u8 bctl = 0;
         u8 presence = 0;
+        struct pci_dev *dev, *temp;
         struct pci_bus *parent = p_slot->ctrl->pcie->port->subordinate;
         u16 command;
         struct controller *ctrl = p_slot->ctrl;
@@ -102,33 +92,31 @@ int pciehp_unconfigure_device(struct slot *p_slot)
         if (ret)
                 presence = 0;
 
-        for (j = 0; j < 8; j++) {
-                struct pci_dev *temp = pci_get_slot(parent, PCI_DEVFN(0, j));
-                if (!temp)
-                        continue;
-                if (temp->hdr_type == PCI_HEADER_TYPE_BRIDGE && presence) {
-                        pci_read_config_byte(temp, PCI_BRIDGE_CONTROL, &bctl);
+        list_for_each_entry_safe(dev, temp, &parent->devices, bus_list) {
+                pci_dev_get(dev);
+                if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE && presence) {
+                        pci_read_config_byte(dev, PCI_BRIDGE_CONTROL, &bctl);
                         if (bctl & PCI_BRIDGE_CTL_VGA) {
                                 ctrl_err(ctrl,
                                          "Cannot remove display device %s\n",
-                                         pci_name(temp));
-                                pci_dev_put(temp);
+                                         pci_name(dev));
+                                pci_dev_put(dev);
                                 rc = -EINVAL;
                                 break;
                         }
                 }
-                pci_stop_and_remove_bus_device(temp);
+                pci_stop_and_remove_bus_device(dev);
                 /*
                  * Ensure that no new Requests will be generated from
                  * the device.
                  */
                 if (presence) {
-                        pci_read_config_word(temp, PCI_COMMAND, &command);
+                        pci_read_config_word(dev, PCI_COMMAND, &command);
                         command &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_SERR);
                         command |= PCI_COMMAND_INTX_DISABLE;
-                        pci_write_config_word(temp, PCI_COMMAND, command);
+                        pci_write_config_word(dev, PCI_COMMAND, command);
                 }
-                pci_dev_put(temp);
+                pci_dev_put(dev);
         }
 
         return rc;