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Wysocki" Subject: [PATCH 06/21] driver core: bus: bus_add/probe/remove_device() cleanups Date: Wed, 8 Feb 2023 12:13:15 +0100 Message-Id: <20230208111330.439504-7-gregkh@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230208111330.439504-1-gregkh@linuxfoundation.org> References: <20230208111330.439504-1-gregkh@linuxfoundation.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4524; i=gregkh@linuxfoundation.org; h=from:subject; bh=bOAbeWNZBH0+KrZBBH/F//OguII8S8sQl/vg+wkJb5k=; b=owGbwMvMwCRo6H6F97bub03G02pJDMmPm6+lT5R4/kji7gp5/di3K3Vzjn2v/Oj9iO3sP8uOROmd kW80O2JZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAiHc8YFnQEb5kplBcbFuphv/53/7 nUG/qnmBjmWUcKmJt7PfNXdFqzIVS0TOHyX752AA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 X-Spam-Status: No, score=-7.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1757261462595845928?= X-GMAIL-MSGID: =?utf-8?q?1757261462595845928?= Convert the bus_add_device(), bus_probe_device(), and bus_remove_device() functions to use bus_to_subsys() and not use the back-pointer to the private structure. Cc: "Rafael J. Wysocki" Signed-off-by: Greg Kroah-Hartman --- drivers/base/bus.c | 87 ++++++++++++++++++++++++++++------------------ 1 file changed, 54 insertions(+), 33 deletions(-) diff --git a/drivers/base/bus.c b/drivers/base/bus.c index f0d3ad41fd5e..f4e4efd81b29 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -466,32 +466,46 @@ EXPORT_SYMBOL_GPL(bus_for_each_drv); */ int bus_add_device(struct device *dev) { - struct bus_type *bus = bus_get(dev->bus); - int error = 0; + struct subsys_private *sp = bus_to_subsys(dev->bus); + int error; - if (bus) { - pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev)); - error = device_add_groups(dev, bus->dev_groups); - if (error) - goto out_put; - error = sysfs_create_link(&bus->p->devices_kset->kobj, - &dev->kobj, dev_name(dev)); - if (error) - goto out_groups; - error = sysfs_create_link(&dev->kobj, - &dev->bus->p->subsys.kobj, "subsystem"); - if (error) - goto out_subsys; - klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices); + if (!sp) { + /* + * This is a normal operation for many devices that do not + * have a bus assigned to them, just say that all went + * well. + */ + return 0; } + + /* + * Reference in sp is now incremented and will be dropped when + * the device is removed from the bus + */ + + pr_debug("bus: '%s': add device %s\n", sp->bus->name, dev_name(dev)); + + error = device_add_groups(dev, sp->bus->dev_groups); + if (error) + goto out_put; + + error = sysfs_create_link(&sp->devices_kset->kobj, &dev->kobj, dev_name(dev)); + if (error) + goto out_groups; + + error = sysfs_create_link(&dev->kobj, &sp->subsys.kobj, "subsystem"); + if (error) + goto out_subsys; + + klist_add_tail(&dev->p->knode_bus, &sp->klist_devices); return 0; out_subsys: - sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev)); + sysfs_remove_link(&sp->devices_kset->kobj, dev_name(dev)); out_groups: - device_remove_groups(dev, bus->dev_groups); + device_remove_groups(dev, sp->bus->dev_groups); out_put: - bus_put(dev->bus); + subsys_put(sp); return error; } @@ -503,20 +517,21 @@ int bus_add_device(struct device *dev) */ void bus_probe_device(struct device *dev) { - struct bus_type *bus = dev->bus; + struct subsys_private *sp = bus_to_subsys(dev->bus); struct subsys_interface *sif; - if (!bus) + if (!sp) return; - if (bus->p->drivers_autoprobe) + if (sp->drivers_autoprobe) device_initial_probe(dev); - mutex_lock(&bus->p->mutex); - list_for_each_entry(sif, &bus->p->interfaces, node) + mutex_lock(&sp->mutex); + list_for_each_entry(sif, &sp->interfaces, node) if (sif->add_dev) sif->add_dev(dev, sif); - mutex_unlock(&bus->p->mutex); + mutex_unlock(&sp->mutex); + subsys_put(sp); } /** @@ -531,21 +546,20 @@ void bus_probe_device(struct device *dev) */ void bus_remove_device(struct device *dev) { - struct bus_type *bus = dev->bus; + struct subsys_private *sp = bus_to_subsys(dev->bus); struct subsys_interface *sif; - if (!bus) + if (!sp) return; - mutex_lock(&bus->p->mutex); - list_for_each_entry(sif, &bus->p->interfaces, node) + mutex_lock(&sp->mutex); + list_for_each_entry(sif, &sp->interfaces, node) if (sif->remove_dev) sif->remove_dev(dev, sif); - mutex_unlock(&bus->p->mutex); + mutex_unlock(&sp->mutex); sysfs_remove_link(&dev->kobj, "subsystem"); - sysfs_remove_link(&dev->bus->p->devices_kset->kobj, - dev_name(dev)); + sysfs_remove_link(&sp->devices_kset->kobj, dev_name(dev)); device_remove_groups(dev, dev->bus->dev_groups); if (klist_node_attached(&dev->p->knode_bus)) klist_del(&dev->p->knode_bus); @@ -553,7 +567,14 @@ void bus_remove_device(struct device *dev) pr_debug("bus: '%s': remove device %s\n", dev->bus->name, dev_name(dev)); device_release_driver(dev); - bus_put(dev->bus); + + /* + * Decrement the reference count twice, once for the bus_to_subsys() + * call in the start of this function, and the second one from the + * reference increment in bus_add_device() + */ + subsys_put(sp); + subsys_put(sp); } static int __must_check add_bind_files(struct device_driver *drv)