This patch enhances PCI remove logic to support PCI bus lock mechanism.
It implements the major part of the PCI bus state machine.
Signed-off-by: Jiang Liu <liu...@gmail.com>
---
drivers/pci/remove.c | 146 +++++++++++++++++++++++++++++---------------------
1 file changed, 85 insertions(+), 61 deletions(-)
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index ba03059..a26a841 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -26,21 +26,25 @@ static void pci_stop_dev(struct pci_dev *dev)
dev->is_added = 0;
}
+ /* TODO: check whether it's safe to call aspm here */
if (dev->bus->self)
pcie_aspm_exit_link_state(dev);
}
static void pci_destroy_dev(struct pci_dev *dev)
{
- /* Remove the device from the device lists, and prevent any further
- * list accesses from this device */
down_write(&pci_bus_sem);
- list_del(&dev->bus_list);
- dev->bus_list.next = dev->bus_list.prev = NULL;
- up_write(&pci_bus_sem);
-
- pci_free_resources(dev);
- put_device(&dev->dev);
+ if (dev->bus_list.next == NULL) {
+ up_write(&pci_bus_sem);
+ } else {
+ /* Remove the device from the device lists, and prevent any
+ * further list accesses from this device */
+ list_del(&dev->bus_list);
+ dev->bus_list.next = dev->bus_list.prev = NULL;
+ up_write(&pci_bus_sem);
+ pci_free_resources(dev);
+ put_device(&dev->dev);
+ }
}
/**
@@ -64,29 +68,44 @@ int pci_remove_device_safe(struct pci_dev *dev)
void pci_remove_bus(struct pci_bus *pci_bus)
{
- pci_proc_detach_bus(pci_bus);
+ int state = pci_bus_get_state(pci_bus);
- down_write(&pci_bus_sem);
- list_del(&pci_bus->node);
- pci_bus_release_busn_res(pci_bus);
- up_write(&pci_bus_sem);
- if (pci_bus->is_added) {
+ switch (state) {
+ case PCI_BUS_STATE_STOPPED:
+ case PCI_BUS_STATE_REGISTERED:
pci_remove_legacy_files(pci_bus);
device_del(&pci_bus->dev);
+ case PCI_BUS_STATE_STOPPING:
+ case PCI_BUS_STATE_INITIALIZED:
+ pci_proc_detach_bus(pci_bus);
+ down_write(&pci_bus_sem);
+ list_del(&pci_bus->node);
+ pci_bus_release_busn_res(pci_bus);
+ up_write(&pci_bus_sem);
+ pci_bus_change_state(pci_bus, state,
+ PCI_BUS_STATE_REMOVED, true);
+ pci_bus_put(pci_bus);
+ break;
+ case PCI_BUS_STATE_REMOVED:
+ pci_bus_unlock(pci_bus);
+ break;
+ default:
+ BUG_ON(state);
+ break;
}
- put_device(&pci_bus->dev);
}
EXPORT_SYMBOL(pci_remove_bus);
-static void pci_remove_behind_bridge(struct pci_dev *dev);
-
void __pci_remove_bus_device(struct pci_dev *dev)
{
- if (dev->subordinate) {
- struct pci_bus *b = dev->subordinate;
+ struct list_head *l, *n;
+ struct pci_bus *bus;
- pci_remove_behind_bridge(dev);
- pci_remove_bus(b);
+ bus = pci_lock_subordinate(dev, PCI_BUS_STATE_DESTROYED - 1);
+ if (bus) {
+ list_for_each_safe(l, n, &bus->devices)
+ __pci_remove_bus_device(pci_dev_b(l));
+ pci_remove_bus(bus);
dev->subordinate = NULL;
}
@@ -111,24 +130,7 @@ void pci_stop_and_remove_bus_device(struct pci_dev *dev)
pci_stop_bus_device(dev);
__pci_remove_bus_device(dev);
}
-
-static void pci_remove_behind_bridge(struct pci_dev *dev)
-{
- struct list_head *l, *n;
-
- if (dev->subordinate)
- list_for_each_safe(l, n, &dev->subordinate->devices)
- __pci_remove_bus_device(pci_dev_b(l));
-}
-
-static void pci_stop_behind_bridge(struct pci_dev *dev)
-{
- struct list_head *l, *n;
-
- if (dev->subordinate)
- list_for_each_safe(l, n, &dev->subordinate->devices)
- pci_stop_bus_device(pci_dev_b(l));
-}
+EXPORT_SYMBOL(pci_stop_and_remove_bus_device);
/**
* pci_stop_and_remove_behind_bridge - stop and remove all devices behind
@@ -141,27 +143,17 @@ static void pci_stop_behind_bridge(struct pci_dev *dev)
*/
void pci_stop_and_remove_behind_bridge(struct pci_dev *dev)
{
- pci_stop_behind_bridge(dev);
- pci_remove_behind_bridge(dev);
-}
-
-static void pci_stop_bus_devices(struct pci_bus *bus)
-{
struct list_head *l, *n;
+ struct pci_bus *bus;
- /*
- * VFs could be removed by pci_stop_and_remove_bus_device() in the
- * pci_stop_bus_devices() code path for PF.
- * aka, bus->devices get updated in the process.
- * but VFs are inserted after PFs when SRIOV is enabled for PF,
- * We can iterate the list backwards to get prev valid PF instead
- * of removed VF.
- */
- list_for_each_prev_safe(l, n, &bus->devices) {
- struct pci_dev *dev = pci_dev_b(l);
- pci_stop_bus_device(dev);
+ bus = pci_lock_subordinate(dev, PCI_BUS_STATE_REMOVED - 1);
+ if (bus) {
+ list_for_each_safe(l, n, &bus->devices)
+ pci_stop_and_remove_bus_device(pci_dev_b(l));
+ pci_bus_unlock(bus);
}
}
+EXPORT_SYMBOL(pci_stop_and_remove_behind_bridge);
/**
* pci_stop_bus_device - stop a PCI device and any children
@@ -173,12 +165,44 @@ static void pci_stop_bus_devices(struct pci_bus *bus)
*/
void pci_stop_bus_device(struct pci_dev *dev)
{
- if (dev->subordinate)
- pci_stop_bus_devices(dev->subordinate);
+ int state;
+ struct pci_bus *bus;
+ struct list_head *l, *n;
+
+ bus = pci_lock_subordinate(dev, PCI_BUS_STATE_REMOVED - 1);
+ if (!bus)
+ goto out;
+
+ state = pci_bus_get_state(bus);
+ switch (state) {
+ case PCI_BUS_STATE_INITIALIZED:
+ pci_bus_change_state(bus, state, PCI_BUS_STATE_STOPPING, true);
+ break;
+ case PCI_BUS_STATE_WORKING:
+ case PCI_BUS_STATE_REGISTERED:
+ pci_bus_change_state(bus, state, PCI_BUS_STATE_STOPPING, false);
+ /*
+ * VFs could be removed by pci_stop_and_remove_bus_device()
+ * in the pci_stop_bus_devices() code path for PF.
+ * aka, bus->devices get updated in the process.
+ * but VFs are inserted after PFs when SRIOV is enabled for PF,
+ * We can iterate the list backwards to get prev valid PF
+ * instead of removed VF.
+ */
+ list_for_each_prev_safe(l, n, &bus->devices)
+ pci_stop_bus_device(pci_dev_b(l));
+ pci_bus_change_state(bus, PCI_BUS_STATE_STOPPING,
+ PCI_BUS_STATE_STOPPED, true);
+ break;
+ case PCI_BUS_STATE_STOPPING:
+ case PCI_BUS_STATE_STOPPED:
+ pci_bus_unlock(bus);
+ break;
+ default:
+ BUG_ON(state);
+ }
+out:
pci_stop_dev(dev);
}
-
-EXPORT_SYMBOL(pci_stop_and_remove_bus_device);
-EXPORT_SYMBOL(pci_stop_and_remove_behind_bridge);
EXPORT_SYMBOL_GPL(pci_stop_bus_device);
--
1.7.9.5
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