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Date: Wed, 8 Aug 2012 00:10:52 +0800
From: Jiang Liu <liuj97@...il.com>
To: Bjorn Helgaas <bhelgaas@...gle.com>,
Don Dutile <ddutile@...hat.com>,
Yinghai Lu <yinghai@...nel.org>,
Greg KH <gregkh@...uxfoundation.org>,
Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
Cc: Jiang Liu <jiang.liu@...wei.com>,
Taku Izumi <izumi.taku@...fujitsu.com>,
"Rafael J . Wysocki" <rjw@...k.pl>,
Yijing Wang <wangyijing@...wei.com>,
Xinwei Hu <huxinwei@...wei.com>, linux-kernel@...r.kernel.org,
linux-pci@...r.kernel.org, Jiang Liu <liuj97@...il.com>
Subject: [RFC PATCH v1 12/22] PCI: enhance PCI remove logic to support PCI bus lock mechanism
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 <liuj97@...il.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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