This patch is meant to try and consolidate all of the locking and unlocking of both the parent and device when attaching or removing a driver from a given device.
To do that I first consolidated the lock pattern into two functions __device_driver_lock and __device_driver_unlock. After doing that I then created functions specific to attaching and detaching the driver while acquiring this locks. By doing this I was able to reduce the number of spots where we touch need_parent_lock from 12 down to 4. Signed-off-by: Alexander Duyck <[email protected]> --- drivers/base/base.h | 2 + drivers/base/bus.c | 23 ++------------ drivers/base/dd.c | 83 ++++++++++++++++++++++++++++++++++++++++++--------- 3 files changed, 75 insertions(+), 33 deletions(-) diff --git a/drivers/base/base.h b/drivers/base/base.h index 7a419a7a6235..3f22ebd6117a 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -124,6 +124,8 @@ extern int driver_add_groups(struct device_driver *drv, const struct attribute_group **groups); extern void driver_remove_groups(struct device_driver *drv, const struct attribute_group **groups); +int device_driver_attach(struct device_driver *drv, struct device *dev); +void device_driver_detach(struct device *dev); extern char *make_class_name(const char *name, struct kobject *kobj); diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 8bfd27ec73d6..8a630f9bd880 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -184,11 +184,7 @@ static ssize_t unbind_store(struct device_driver *drv, const char *buf, dev = bus_find_device_by_name(bus, NULL, buf); if (dev && dev->driver == drv) { - if (dev->parent && dev->bus->need_parent_lock) - device_lock(dev->parent); - device_release_driver(dev); - if (dev->parent && dev->bus->need_parent_lock) - device_unlock(dev->parent); + device_driver_detach(dev); err = count; } put_device(dev); @@ -211,13 +207,7 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, dev = bus_find_device_by_name(bus, NULL, buf); if (dev && dev->driver == NULL && driver_match_device(drv, dev)) { - if (dev->parent && bus->need_parent_lock) - device_lock(dev->parent); - device_lock(dev); - err = driver_probe_device(drv, dev); - device_unlock(dev); - if (dev->parent && bus->need_parent_lock) - device_unlock(dev->parent); + err = device_driver_attach(drv, dev); if (err > 0) { /* success */ @@ -769,13 +759,8 @@ int bus_rescan_devices(struct bus_type *bus) */ int device_reprobe(struct device *dev) { - if (dev->driver) { - if (dev->parent && dev->bus->need_parent_lock) - device_lock(dev->parent); - device_release_driver(dev); - if (dev->parent && dev->bus->need_parent_lock) - device_unlock(dev->parent); - } + if (dev->driver) + device_driver_detach(dev); return bus_rescan_devices_helper(dev, NULL); } EXPORT_SYMBOL_GPL(device_reprobe); diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 169412ee4ae8..e845cd2a87af 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -864,6 +864,60 @@ 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_lock - 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 (!dev->driver) + ret = driver_probe_device(drv, dev); + + __device_driver_unlock(dev, dev->parent); + + return ret; +} + static int __driver_attach(struct device *dev, void *data) { struct device_driver *drv = data; @@ -891,14 +945,7 @@ 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); + device_driver_attach(drv, dev); return 0; } @@ -993,16 +1040,12 @@ 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 +1071,18 @@ 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 + * + * Manually 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. */
