diff options
Diffstat (limited to 'drivers/base/dd.c')
| -rw-r--r-- | drivers/base/dd.c | 188 |
1 files changed, 155 insertions, 33 deletions
diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 8ac10af17c00..a823f469e53f 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -57,6 +57,10 @@ static atomic_t deferred_trigger_count = ATOMIC_INIT(0); static struct dentry *deferred_devices; static bool initcalls_done; +/* Save the async probe drivers' name from kernel cmdline */ +#define ASYNC_DRV_NAMES_MAX_LEN 256 +static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN]; + /* * In some cases, like suspend to RAM or hibernation, It might be reasonable * to prohibit probing of devices as it could be unsafe. @@ -116,7 +120,7 @@ static void deferred_probe_work_func(struct work_struct *work) } static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func); -static void driver_deferred_probe_add(struct device *dev) +void driver_deferred_probe_add(struct device *dev) { mutex_lock(&deferred_probe_mutex); if (list_empty(&dev->p->deferred_probe)) { @@ -674,6 +678,23 @@ int driver_probe_device(struct device_driver *drv, struct device *dev) return ret; } +static inline bool cmdline_requested_async_probing(const char *drv_name) +{ + return parse_option_str(async_probe_drv_names, drv_name); +} + +/* The option format is "driver_async_probe=drv_name1,drv_name2,..." */ +static int __init save_async_options(char *buf) +{ + if (strlen(buf) >= ASYNC_DRV_NAMES_MAX_LEN) + printk(KERN_WARNING + "Too long list of driver names for 'driver_async_probe'!\n"); + + strlcpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN); + return 0; +} +__setup("driver_async_probe=", save_async_options); + bool driver_allows_async_probing(struct device_driver *drv) { switch (drv->probe_type) { @@ -684,6 +705,9 @@ bool driver_allows_async_probing(struct device_driver *drv) return false; default: + if (cmdline_requested_async_probing(drv->name)) + return true; + if (module_requested_async_probing(drv->owner)) return true; @@ -731,15 +755,6 @@ static int __device_attach_driver(struct device_driver *drv, void *_data) bool async_allowed; int ret; - /* - * Check if device has already been claimed. This may - * happen with driver loading, device discovery/registration, - * and deferred probe processing happens all at once with - * multiple threads. - */ - if (dev->driver) - return -EBUSY; - ret = driver_match_device(drv, dev); if (ret == 0) { /* no match */ @@ -774,6 +789,15 @@ static void __device_attach_async_helper(void *_dev, async_cookie_t cookie) device_lock(dev); + /* + * Check if device has already been removed or claimed. This may + * happen with driver loading, device discovery/registration, + * and deferred probe processing happens all at once with + * multiple threads. + */ + if (dev->p->dead || dev->driver) + goto out_unlock; + if (dev->parent) pm_runtime_get_sync(dev->parent); @@ -784,7 +808,7 @@ static void __device_attach_async_helper(void *_dev, async_cookie_t cookie) if (dev->parent) pm_runtime_put(dev->parent); - +out_unlock: device_unlock(dev); put_device(dev); @@ -829,7 +853,7 @@ static int __device_attach(struct device *dev, bool allow_async) */ dev_dbg(dev, "scheduling asynchronous probe\n"); get_device(dev); - async_schedule(__device_attach_async_helper, dev); + async_schedule_dev(__device_attach_async_helper, dev); } else { pm_request_idle(dev); } @@ -867,6 +891,88 @@ void device_initial_probe(struct device *dev) __device_attach(dev, true); } +/* + * __device_driver_lock - acquire locks needed to manipulate dev->drv + * @dev: Device we will update driver info for + * @parent: Parent device. Needed if the bus requires parent lock + * + * This function will take the required locks for manipulating dev->drv. + * Normally this will just be the @dev lock, but when called for a USB + * interface, @parent lock will be held as well. + */ +static void __device_driver_lock(struct device *dev, struct device *parent) +{ + if (parent && dev->bus->need_parent_lock) + device_lock(parent); + device_lock(dev); +} + +/* + * __device_driver_unlock - release locks needed to manipulate dev->drv + * @dev: Device we will update driver info for + * @parent: Parent device. Needed if the bus requires parent lock + * + * This function will release the required locks for manipulating dev->drv. + * Normally this will just be the the @dev lock, but when called for a + * USB interface, @parent lock will be released as well. + */ +static void __device_driver_unlock(struct device *dev, struct device *parent) +{ + device_unlock(dev); + if (parent && dev->bus->need_parent_lock) + device_unlock(parent); +} + +/** + * device_driver_attach - attach a specific driver to a specific device + * @drv: Driver to attach + * @dev: Device to attach it to + * + * Manually attach driver to a device. Will acquire both @dev lock and + * @dev->parent lock if needed. + */ +int device_driver_attach(struct device_driver *drv, struct device *dev) +{ + int ret = 0; + + __device_driver_lock(dev, dev->parent); + + /* + * If device has been removed or someone has already successfully + * bound a driver before us just skip the driver probe call. + */ + if (!dev->p->dead && !dev->driver) + ret = driver_probe_device(drv, dev); + + __device_driver_unlock(dev, dev->parent); + + return ret; +} + +static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie) +{ + struct device *dev = _dev; + struct device_driver *drv; + int ret = 0; + + __device_driver_lock(dev, dev->parent); + + drv = dev->p->async_driver; + + /* + * If device has been removed or someone has already successfully + * bound a driver before us just skip the driver probe call. + */ + if (!dev->p->dead && !dev->driver) + ret = driver_probe_device(drv, dev); + + __device_driver_unlock(dev, dev->parent); + + dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret); + + put_device(dev); +} + static int __driver_attach(struct device *dev, void *data) { struct device_driver *drv = data; @@ -894,14 +1000,26 @@ static int __driver_attach(struct device *dev, void *data) return ret; } /* ret > 0 means positive match */ - if (dev->parent && dev->bus->need_parent_lock) - device_lock(dev->parent); - device_lock(dev); - if (!dev->driver) - driver_probe_device(drv, dev); - device_unlock(dev); - if (dev->parent && dev->bus->need_parent_lock) - device_unlock(dev->parent); + if (driver_allows_async_probing(drv)) { + /* + * Instead of probing the device synchronously we will + * probe it asynchronously to allow for more parallelism. + * + * We only take the device lock here in order to guarantee + * that the dev->driver and async_driver fields are protected + */ + dev_dbg(dev, "probing driver %s asynchronously\n", drv->name); + device_lock(dev); + if (!dev->driver) { + get_device(dev); + dev->p->async_driver = drv; + async_schedule_dev(__driver_attach_async_helper, dev); + } + device_unlock(dev); + return 0; + } + + device_driver_attach(drv, dev); return 0; } @@ -932,15 +1050,11 @@ static void __device_release_driver(struct device *dev, struct device *parent) drv = dev->driver; if (drv) { while (device_links_busy(dev)) { - device_unlock(dev); - if (parent && dev->bus->need_parent_lock) - device_unlock(parent); + __device_driver_unlock(dev, parent); device_links_unbind_consumers(dev); - if (parent && dev->bus->need_parent_lock) - device_lock(parent); - device_lock(dev); + __device_driver_lock(dev, parent); /* * A concurrent invocation of the same function might * have released the driver successfully while this one @@ -968,9 +1082,9 @@ static void __device_release_driver(struct device *dev, struct device *parent) drv->remove(dev); device_links_driver_cleanup(dev); - arch_teardown_dma_ops(dev); devres_release_all(dev); + arch_teardown_dma_ops(dev); dev->driver = NULL; dev_set_drvdata(dev, NULL); if (dev->pm_domain && dev->pm_domain->dismiss) @@ -993,16 +1107,12 @@ void device_release_driver_internal(struct device *dev, struct device_driver *drv, struct device *parent) { - if (parent && dev->bus->need_parent_lock) - device_lock(parent); + __device_driver_lock(dev, parent); - device_lock(dev); if (!drv || drv == dev->driver) __device_release_driver(dev, parent); - device_unlock(dev); - if (parent && dev->bus->need_parent_lock) - device_unlock(parent); + __device_driver_unlock(dev, parent); } /** @@ -1028,6 +1138,18 @@ void device_release_driver(struct device *dev) EXPORT_SYMBOL_GPL(device_release_driver); /** + * device_driver_detach - detach driver from a specific device + * @dev: device to detach driver from + * + * Detach driver from device. Will acquire both @dev lock and @dev->parent + * lock if needed. + */ +void device_driver_detach(struct device *dev) +{ + device_release_driver_internal(dev, NULL, dev->parent); +} + +/** * driver_detach - detach driver from all devices it controls. * @drv: driver. */ |