On Wed, Nov 28, 2018 at 04:32:21PM -0800, Alexander Duyck wrote: > Try to 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 these locks. By doing this I was able to reduce the number of > spots where we touch need_parent_lock from 12 down to 4.
While this later is true, it gives the impression there are functional changes but I see none. It can help reviewers / future reviewers of this commit if its clearly stated that this patch introduces no functional changes. > Reviewed-by: Bart Van Assche <[email protected]> > Reviewed-by: Dan Williams <[email protected]> > Reviewed-by: Rafael J. Wysocki <[email protected]> > Signed-off-by: Alexander Duyck <[email protected]> Reviewed-by: Luis Chamberlain <[email protected]> Luis > --- > drivers/base/base.h | 2 + > drivers/base/bus.c | 23 ++----------- > drivers/base/dd.c | 91 > ++++++++++++++++++++++++++++++++++++++++----------- > 3 files changed, 77 insertions(+), 39 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 @@ EXPORT_SYMBOL_GPL(bus_rescan_devices); > */ > 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 ef3f70a7cb5a..d2515520569e 100644 > --- a/drivers/base/dd.c > +++ b/drivers/base/dd.c > @@ -875,6 +875,60 @@ 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_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 (!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; > @@ -902,14 +956,7 @@ 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; > } > @@ -948,15 +995,11 @@ 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) > - device_unlock(parent); > + __device_driver_unlock(dev, parent); > > device_links_unbind_consumers(dev); > - if (parent) > - 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 > @@ -1009,16 +1052,12 @@ 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); > } > > /** > @@ -1043,6 +1082,18 @@ 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. > _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
