This patch uses PCI bus lock mechanism to avoid race conditions when doing
PCI device/host bridge hotplug through PCI sysfs interfaces.
Signed-off-by: Jiang Liu <liu...@gmail.com>
---
drivers/pci/pci-sysfs.c | 26 +++++++++++++++++++++-----
drivers/pci/probe.c | 17 +++++++++++------
2 files changed, 32 insertions(+), 11 deletions(-)
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 99fefbe..11043b4 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -298,7 +298,10 @@ static ssize_t bus_rescan_store(struct bus_type *bus,
const char *buf,
pci_host_bridge_hotplug_lock();
mutex_lock(&pci_remove_rescan_mutex);
while ((b = pci_find_next_bus(b)) != NULL)
- pci_rescan_bus(b);
+ if (pci_bus_lock_states(b, PCI_BUS_STATE_WORKING) > 0) {
+ pci_rescan_bus(b);
+ pci_bus_unlock(b);
+ }
mutex_unlock(&pci_remove_rescan_mutex);
pci_host_bridge_hotplug_unlock();
}
@@ -321,8 +324,14 @@ dev_rescan_store(struct device *dev, struct
device_attribute *attr,
return -EINVAL;
if (val) {
+ struct pci_bus *bus = pdev->bus;
+
mutex_lock(&pci_remove_rescan_mutex);
- pci_rescan_bus(pdev->bus);
+ if (pci_bus_lock_states(bus, PCI_BUS_STATE_WORKING) > 0) {
+ if (pdev->is_added)
+ pci_rescan_bus(bus);
+ pci_bus_unlock(bus);
+ }
mutex_unlock(&pci_remove_rescan_mutex);
}
return count;
@@ -331,9 +340,14 @@ dev_rescan_store(struct device *dev, struct
device_attribute *attr,
static void remove_callback(struct device *dev)
{
struct pci_dev *pdev = to_pci_dev(dev);
+ struct pci_bus *bus = pdev->bus;
mutex_lock(&pci_remove_rescan_mutex);
- pci_stop_and_remove_bus_device(pdev);
+ if (pci_bus_lock_states(bus, PCI_BUS_STATE_WORKING) > 0) {
+ pci_bus_get(bus);
+ pci_stop_and_remove_bus_device(pdev);
+ pci_unlock_and_put_bus(bus);
+ }
mutex_unlock(&pci_remove_rescan_mutex);
}
@@ -369,10 +383,12 @@ dev_bus_rescan_store(struct device *dev, struct
device_attribute *attr,
if (val) {
mutex_lock(&pci_remove_rescan_mutex);
- if (!pci_is_root_bus(bus) && list_empty(&bus->devices))
+ if (!pci_is_root_bus(bus))
pci_rescan_bus_bridge_resize(bus->self);
- else
+ else if (pci_bus_lock_states(bus, PCI_BUS_STATE_WORKING) > 0) {
pci_rescan_bus(bus);
+ pci_bus_unlock(bus);
+ }
mutex_unlock(&pci_remove_rescan_mutex);
}
return count;
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 47bf071..da6f04c 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1919,12 +1919,17 @@ EXPORT_SYMBOL(pci_scan_bus);
unsigned int __ref pci_rescan_bus_bridge_resize(struct pci_dev *bridge)
{
unsigned int max = -1;
- struct pci_bus *bus = bridge->subordinate;
-
- if (pci_bus_lock_states(bus, PCI_BUS_STATE_WORKING) > 0) {
- max = pci_scan_child_bus(bus);
- pci_assign_unassigned_bridge_resources(bridge);
- pci_bus_add_devices(bus);
+ struct pci_bus *bus;
+
+ bus = pci_lock_subordinate(bridge, PCI_BUS_STATE_WORKING);
+ if (bus) {
+ if (list_empty(&bus->devices)) {
+ max = pci_scan_child_bus(bus);
+ pci_assign_unassigned_bridge_resources(bridge);
+ pci_bus_add_devices(bus);
+ } else {
+ pci_rescan_bus(bus);
+ }
pci_bus_unlock(bus);
}
--
1.7.9.5
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