ACPI / hotplug / PCI: Use global PCI rescan-remove locking
Multiple race conditions are possible between the ACPI-based PCI hotplug
(ACPIPHP) and the generic PCI bus rescan and device removal that can be
triggered via sysfs.
To avoid those race conditions make the ACPIPHP code use global PCI
rescan-remove locking.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 1cf605f..641ba67 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -430,6 +430,7 @@
pr_err("failed to remove notify handler\n");
}
}
+ slot->flags |= SLOT_IS_GOING_AWAY;
if (slot->slot)
acpiphp_unregister_hotplug_slot(slot);
}
@@ -437,6 +438,8 @@
mutex_lock(&bridge_mutex);
list_del(&bridge->list);
mutex_unlock(&bridge_mutex);
+
+ bridge->is_going_away = true;
}
/**
@@ -736,6 +739,10 @@
{
struct acpiphp_slot *slot;
+ /* Bail out if the bridge is going away. */
+ if (bridge->is_going_away)
+ return;
+
list_for_each_entry(slot, &bridge->slots, node) {
struct pci_bus *bus = slot->bus;
struct pci_dev *dev, *tmp;
@@ -805,6 +812,8 @@
}
}
+static int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot);
+
static void hotplug_event(acpi_handle handle, u32 type, void *data)
{
struct acpiphp_context *context = data;
@@ -834,6 +843,9 @@
} else {
struct acpiphp_slot *slot = func->slot;
+ if (slot->flags & SLOT_IS_GOING_AWAY)
+ break;
+
mutex_lock(&slot->crit_sect);
enable_slot(slot);
mutex_unlock(&slot->crit_sect);
@@ -849,6 +861,9 @@
struct acpiphp_slot *slot = func->slot;
int ret;
+ if (slot->flags & SLOT_IS_GOING_AWAY)
+ break;
+
/*
* Check if anything has changed in the slot and rescan
* from the parent if that's the case.
@@ -878,9 +893,11 @@
acpi_handle handle = context->handle;
acpi_scan_lock_acquire();
+ pci_lock_rescan_remove();
hotplug_event(handle, type, context);
+ pci_unlock_rescan_remove();
acpi_scan_lock_release();
acpi_evaluate_hotplug_ost(handle, type, ACPI_OST_SC_SUCCESS, NULL);
put_bridge(context->func.parent);
@@ -1048,12 +1065,19 @@
*/
int acpiphp_enable_slot(struct acpiphp_slot *slot)
{
+ pci_lock_rescan_remove();
+
+ if (slot->flags & SLOT_IS_GOING_AWAY)
+ return -ENODEV;
+
mutex_lock(&slot->crit_sect);
/* configure all functions */
if (!(slot->flags & SLOT_ENABLED))
enable_slot(slot);
mutex_unlock(&slot->crit_sect);
+
+ pci_unlock_rescan_remove();
return 0;
}
@@ -1061,10 +1085,12 @@
* acpiphp_disable_and_eject_slot - power off and eject slot
* @slot: ACPI PHP slot
*/
-int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot)
+static int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot)
{
struct acpiphp_func *func;
- int retval = 0;
+
+ if (slot->flags & SLOT_IS_GOING_AWAY)
+ return -ENODEV;
mutex_lock(&slot->crit_sect);
@@ -1082,9 +1108,18 @@
}
mutex_unlock(&slot->crit_sect);
- return retval;
+ return 0;
}
+int acpiphp_disable_slot(struct acpiphp_slot *slot)
+{
+ int ret;
+
+ pci_lock_rescan_remove();
+ ret = acpiphp_disable_and_eject_slot(slot);
+ pci_unlock_rescan_remove();
+ return ret;
+}
/*
* slot enabled: 1
@@ -1095,7 +1130,6 @@
return (slot->flags & SLOT_ENABLED);
}
-
/*
* latch open: 1
* latch closed: 0
@@ -1105,7 +1139,6 @@
return !(get_slot_status(slot) & ACPI_STA_DEVICE_UI);
}
-
/*
* adapter presence : 1
* absence : 0