struct pci_dev has a one bit flag (is_added) to store PCI device state,
but it's not enough to protect PCI devices from concurrent PCI hotplug
operations. So extend the one bit is_added flag as a three bits
dev_state field and introduce a simple state machine for PCI device
objects as:
INITIALIZED -> STARTED -> STOPPING -> STOPPED -> REMOVED
The state machine is used to protect PCI devices from multiple invokes
of pci_stop_dev() and pci_destroy_dev() for the same PCI device object.
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>
Cc: Yijing Wang <wangyijing@xxxxxxxxxx>
Cc: linux-pci@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
drivers/pci/bus.c | 14 ++++++++------
drivers/pci/hotplug/acpiphp_glue.c | 2 +-
drivers/pci/probe.c | 7 +++----
drivers/pci/remove.c | 31 ++++++++++++++++++++-----------
include/linux/pci.h | 15 ++++++++++++++-
5 files changed, 46 insertions(+), 23 deletions(-)
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 8ea5972..913608e 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -183,7 +183,7 @@ int pci_bus_add_device(struct pci_dev *dev)
retval = device_attach(&dev->dev);
WARN_ON(retval < 0);
- dev->is_added = 1;
+ dev->dev_state = PCI_DEV_STATE_STARTED;
return 0;
}
@@ -211,7 +211,7 @@ void pci_bus_add_devices(const struct pci_bus *bus)
list_for_each_entry(dev, &bus->devices, bus_list) {
/* Skip already-added devices */
- if (dev->is_added)
+ if (dev->dev_state >= PCI_DEV_STATE_STARTED)
continue;
retval = pci_bus_add_device(dev);
if (retval)
@@ -220,10 +220,12 @@ void pci_bus_add_devices(const struct pci_bus *bus)
}
list_for_each_entry(dev, &bus->devices, bus_list) {
- BUG_ON(!dev->is_added);
- child = dev->subordinate;
- if (child)
- pci_bus_add_devices(child);
+ BUG_ON(dev->dev_state < PCI_DEV_STATE_STARTED);
+ if (dev->dev_state == PCI_DEV_STATE_STARTED) {
+ child = dev->subordinate;
+ if (child)
+ pci_bus_add_devices(child);
+ }
}
}
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 96fed19..e330331 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -708,7 +708,7 @@ static int __ref enable_device(struct acpiphp_slot *slot)
list_for_each_entry(dev, &bus->devices, bus_list) {
/* Assume that newly added devices are powered on already. */
- if (!dev->is_added)
+ if (dev->dev_state == PCI_DEV_STATE_INITIALIZED)
dev->current_state = PCI_D0;
}
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 4e24d93..9fcf3a3 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1433,8 +1433,7 @@ static int only_one_child(struct pci_bus *bus)
* @devfn: slot number to scan (must have zero function.)
*
* Scan a PCI slot on the specified PCI bus for devices, adding
- * discovered devices to the @bus->devices list. New devices
- * will not have is_added set.
+ * discovered devices to the @bus->devices list.
*
* Returns the number of new devices found.
*/
@@ -1449,13 +1448,13 @@ int pci_scan_slot(struct pci_bus *bus, int devfn)
dev = pci_scan_single_device(bus, devfn);
if (!dev)
return 0;
- if (!dev->is_added)
+ if (dev->dev_state == PCI_DEV_STATE_INITIALIZED)
nr++;
for (fn = next_fn(bus, dev, 0); fn > 0; fn = next_fn(bus, dev, fn)) {
dev = pci_scan_single_device(bus, devfn + fn);
if (dev) {
- if (!dev->is_added)
+ if (dev->dev_state == PCI_DEV_STATE_INITIALIZED)
nr++;
dev->multifunction = 1;
}
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index effe4ff..2f01f72 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -10,7 +10,7 @@ static void pci_free_resources(struct pci_dev *dev)
{
int i;
- msi_remove_pci_irq_vectors(dev);
+ msi_remove_pci_irq_vectors(dev);
pci_cleanup_rom(dev);
for (i = 0; i < PCI_NUM_RESOURCES; i++) {
@@ -22,27 +22,36 @@ static void pci_free_resources(struct pci_dev *dev)
static void pci_stop_dev(struct pci_dev *dev)
{
- pci_pme_active(dev, false);
+ bool started;
+
+ BUG_ON(dev->dev_state == PCI_DEV_STATE_STOPPING);
+ if (dev->dev_state >= PCI_DEV_STATE_STOPPED)
+ return;
- if (dev->is_added) {
+ started = dev->dev_state == PCI_DEV_STATE_STARTED;
+ dev->dev_state = PCI_DEV_STATE_STOPPING;
+ pci_pme_active(dev, false);
+ if (started) {
pci_proc_detach_device(dev);
pci_remove_sysfs_dev_files(dev);
device_del(&dev->dev);
- dev->is_added = 0;
}
-
if (dev->bus->self)
pcie_aspm_exit_link_state(dev);
+
+ dev->dev_state = PCI_DEV_STATE_STOPPED;
}
static void pci_destroy_dev(struct pci_dev *dev)
{
- down_write(&pci_bus_sem);
- list_del(&dev->bus_list);
- up_write(&pci_bus_sem);
-
- pci_free_resources(dev);
- put_device(&dev->dev);
+ if (dev->dev_state < PCI_DEV_STATE_REMOVED) {
+ down_write(&pci_bus_sem);
+ list_del(&dev->bus_list);
+ up_write(&pci_bus_sem);
+ pci_free_resources(dev);
+ put_device(&dev->dev);
+ dev->dev_state = PCI_DEV_STATE_REMOVED;
+ }
}
void pci_remove_bus(struct pci_bus *bus)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index cfe075c..d3f61f8 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -210,6 +210,14 @@ enum pci_bus_speed {
PCI_SPEED_UNKNOWN = 0xff,
};
+enum pci_dev_state {
+ PCI_DEV_STATE_INITIALIZED = 0,
+ PCI_DEV_STATE_STARTED = 1,
+ PCI_DEV_STATE_STOPPING = 2,
+ PCI_DEV_STATE_STOPPED = 3,
+ PCI_DEV_STATE_REMOVED = 4,
+};
+
struct pci_cap_saved_data {
char cap_nr;
unsigned int size;
@@ -307,7 +315,7 @@ struct pci_dev {
unsigned int transparent:1; /* Transparent PCI bridge */
unsigned int multifunction:1;/* Part of multi-function device */
/* keep track of device state */
- unsigned int is_added:1;
+ unsigned int dev_state:3;
unsigned int is_busmaster:1; /* device is busmaster */
unsigned int no_msi:1; /* device may not use msi */
unsigned int block_cfg_access:1; /* config space access is blocked */
@@ -367,6 +375,11 @@ static inline struct pci_dev *pci_physfn(struct pci_dev *dev)
struct pci_dev *pci_alloc_dev(struct pci_bus *bus);
struct pci_dev * __deprecated alloc_pci_dev(void);
+static inline int pci_dev_get_state(struct pci_dev *pdev)
+{
+ return (volatile int)pdev->dev_state;
+}
+
#define to_pci_dev(n) container_of(n, struct pci_dev, dev)
#define for_each_pci_dev(d) while ((d = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, d)) != NULL)
--
1.8.1.2
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