diff options
Diffstat (limited to 'drivers/base/dd.c')
| -rw-r--r-- | drivers/base/dd.c | 81 |
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); - } } |