From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 20D582118D948 for ; Thu, 8 Nov 2018 10:06:56 -0800 (PST) Subject: [driver-core PATCH v6 3/9] device core: Consolidate locking and unlocking of parent and device From: Alexander Duyck Date: Thu, 08 Nov 2018 10:06:55 -0800 Message-ID: <154170041590.12967.4367086895437513524.stgit@ahduyck-desk1.jf.intel.com> In-Reply-To: <154170028986.12967.2108024712555179678.stgit@ahduyck-desk1.jf.intel.com> References: <154170028986.12967.2108024712555179678.stgit@ahduyck-desk1.jf.intel.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org Cc: len.brown@intel.com, bvanassche@acm.org, linux-pm@vger.kernel.org, alexander.h.duyck@linux.intel.com, rafael@kernel.org, jiangshanlai@gmail.com, linux-nvdimm@lists.01.org, pavel@ucw.cz, zwisler@kernel.org, tj@kernel.org, akpm@linux-foundation.org List-ID: 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. Reviewed-by: Bart Van Assche Reviewed-by: Rafael J. Wysocki Signed-off-by: Alexander Duyck --- 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 169412ee4ae8..76c40fe69463 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; } @@ -932,15 +979,11 @@ static void __device_release_driver(struct device *dev, struct device *parent) async_synchronize_full(); 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 @@ -993,16 +1036,12 @@ 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); } /** @@ -1027,6 +1066,18 @@ 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 Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm