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path: root/drivers/base/dd.c
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Diffstat (limited to 'drivers/base/dd.c')
-rw-r--r--drivers/base/dd.c81
1 files changed, 76 insertions, 5 deletions
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index a641cf3cc..c4da2df62 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -55,6 +55,13 @@ static struct workqueue_struct *deferred_wq;
static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
/*
+ * In some cases, like suspend to RAM or hibernation, It might be reasonable
+ * to prohibit probing of devices as it could be unsafe.
+ * Once defer_all_probes is true all drivers probes will be forcibly deferred.
+ */
+static bool defer_all_probes;
+
+/*
* deferred_probe_work_func() - Retry probing devices in the active list.
*/
static void deferred_probe_work_func(struct work_struct *work)
@@ -172,6 +179,30 @@ static void driver_deferred_probe_trigger(void)
}
/**
+ * device_block_probing() - Block/defere device's probes
+ *
+ * It will disable probing of devices and defer their probes instead.
+ */
+void device_block_probing(void)
+{
+ defer_all_probes = true;
+ /* sync with probes to avoid races. */
+ wait_for_device_probe();
+}
+
+/**
+ * device_unblock_probing() - Unblock/enable device's probes
+ *
+ * It will restore normal behavior and trigger re-probing of deferred
+ * devices.
+ */
+void device_unblock_probing(void)
+{
+ defer_all_probes = false;
+ driver_deferred_probe_trigger();
+}
+
+/**
* deferred_probe_initcall() - Enable probing of deferred devices
*
* We don't want to get in the way when the bulk of drivers are getting probed.
@@ -192,9 +223,23 @@ static int deferred_probe_initcall(void)
}
late_initcall(deferred_probe_initcall);
+/**
+ * device_is_bound() - Check if device is bound to a driver
+ * @dev: device to check
+ *
+ * Returns true if passed device has already finished probing successfully
+ * against a driver.
+ *
+ * This function must be called with the device lock held.
+ */
+bool device_is_bound(struct device *dev)
+{
+ return dev->p && klist_node_attached(&dev->p->knode_driver);
+}
+
static void driver_bound(struct device *dev)
{
- if (klist_node_attached(&dev->p->knode_driver)) {
+ if (device_is_bound(dev)) {
printk(KERN_WARNING "%s: device %s already bound\n",
__func__, kobject_name(&dev->kobj));
return;
@@ -205,6 +250,8 @@ static void driver_bound(struct device *dev)
klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
+ device_pm_check_callbacks(dev);
+
/*
* Make sure the device is no longer in one of the deferred lists and
* kick off retrying all pending devices
@@ -268,6 +315,9 @@ int device_bind_driver(struct device *dev)
ret = driver_sysfs_add(dev);
if (!ret)
driver_bound(dev);
+ else if (dev->bus)
+ blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
+ BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
return ret;
}
EXPORT_SYMBOL_GPL(device_bind_driver);
@@ -277,9 +327,20 @@ static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
static int really_probe(struct device *dev, struct device_driver *drv)
{
- int ret = 0;
+ int ret = -EPROBE_DEFER;
int local_trigger_count = atomic_read(&deferred_trigger_count);
+ if (defer_all_probes) {
+ /*
+ * Value of defer_all_probes can be set only by
+ * device_defer_all_probes_enable() which, in turn, will call
+ * wait_for_device_probe() right after that to avoid any races.
+ */
+ dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
+ driver_deferred_probe_add(dev);
+ return ret;
+ }
+
atomic_inc(&probe_count);
pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
drv->bus->name, __func__, drv->name, dev_name(dev));
@@ -290,7 +351,7 @@ static int really_probe(struct device *dev, struct device_driver *drv)
/* If using pinctrl, bind pins now before probing */
ret = pinctrl_bind_pins(dev);
if (ret)
- goto probe_failed;
+ goto pinctrl_bind_failed;
if (driver_sysfs_add(dev)) {
printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
@@ -334,12 +395,17 @@ static int really_probe(struct device *dev, struct device_driver *drv)
goto done;
probe_failed:
+ if (dev->bus)
+ blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
+ BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
+pinctrl_bind_failed:
devres_release_all(dev);
driver_sysfs_remove(dev);
dev->driver = NULL;
dev_set_drvdata(dev, NULL);
if (dev->pm_domain && dev->pm_domain->dismiss)
dev->pm_domain->dismiss(dev);
+ pm_runtime_reinit(dev);
switch (ret) {
case -EPROBE_DEFER:
@@ -393,6 +459,10 @@ int driver_probe_done(void)
*/
void wait_for_device_probe(void)
{
+ /* wait for the deferred probe workqueue to finish */
+ if (driver_deferred_probe_enable)
+ flush_workqueue(deferred_wq);
+
/* wait for the known devices to complete their probing */
wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
async_synchronize_full();
@@ -547,7 +617,7 @@ static int __device_attach(struct device *dev, bool allow_async)
device_lock(dev);
if (dev->driver) {
- if (klist_node_attached(&dev->p->knode_driver)) {
+ if (device_is_bound(dev)) {
ret = 1;
goto out_unlock;
}
@@ -695,13 +765,14 @@ static void __device_release_driver(struct device *dev)
dev_set_drvdata(dev, NULL);
if (dev->pm_domain && dev->pm_domain->dismiss)
dev->pm_domain->dismiss(dev);
+ pm_runtime_reinit(dev);
klist_remove(&dev->p->knode_driver);
+ device_pm_check_callbacks(dev);
if (dev->bus)
blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
BUS_NOTIFY_UNBOUND_DRIVER,
dev);
-
}
}