Driver core patches for 4.3-rc1

Here is the new patches for the driver core / sysfs for 4.3-rc1.
 
 Very small number of changes here, all the details are in the shortlog,
 nothing major happening at all this kernel release, which is nice to
 see.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-4.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the new patches for the driver core / sysfs for 4.3-rc1.

  Very small number of changes here, all the details are in the
  shortlog, nothing major happening at all this kernel release, which is
  nice to see"

* tag 'driver-core-4.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  bus: subsys: update return type of ->remove_dev() to void
  driver core: correct device's shutdown order
  driver core: fix docbook for device_private.device
  selftests: firmware: skip timeout checks for kernels without user mode helper
  kernel, cpu: Remove bogus __ref annotations
  cpu: Remove bogus __ref annotation of cpu_subsys_online()
  firmware: fix wrong memory deallocation in fw_add_devm_name()
  sysfs.txt: update show method notes about sprintf/snprintf/scnprintf usage
  devres: fix devres_get()

Documentation/filesystems/sysfs.txt

@@ -212,7 +212,10 @@ Other notes:
 - show() methods should return the number of bytes printed into the
   buffer. This is the return value of scnprintf().
 
-- show() should always use scnprintf().
+- show() must not use snprintf() when formatting the value to be
+  returned to user space. If you can guarantee that an overflow
+  will never happen you can use sprintf() otherwise you must use
+  scnprintf().
 
 - store() should return the number of bytes used from the buffer. If the
   entire buffer has been used, just return the count argument.

arch/sh/kernel/cpu/sh4/sq.c

@@ -355,13 +355,12 @@ static int sq_dev_add(struct device *dev, struct subsys_interface *sif)
 	return error;
 }
 
-static int sq_dev_remove(struct device *dev, struct subsys_interface *sif)
+static void sq_dev_remove(struct device *dev, struct subsys_interface *sif)
 {
 	unsigned int cpu = dev->id;
 	struct kobject *kobj = sq_kobject[cpu];
 
 	kobject_put(kobj);
-	return 0;
 }
 
 static struct subsys_interface sq_interface = {

arch/tile/kernel/sysfs.c

@@ -198,16 +198,13 @@ static int hv_stats_device_add(struct device *dev, struct subsys_interface *sif)
 	return err;
 }
 
-static int hv_stats_device_remove(struct device *dev,
-				  struct subsys_interface *sif)
+static void hv_stats_device_remove(struct device *dev,
+				   struct subsys_interface *sif)
 {
 	int cpu = dev->id;
 
-	if (!cpu_online(cpu))
-		return 0;
-
-	sysfs_remove_file(&dev->kobj, &dev_attr_hv_stats.attr);
-	return 0;
+	if (cpu_online(cpu))
+		sysfs_remove_file(&dev->kobj, &dev_attr_hv_stats.attr);
 }
 
 

arch/x86/kernel/cpu/microcode/core.c

@@ -377,17 +377,16 @@ static int mc_device_add(struct device *dev, struct subsys_interface *sif)
 	return err;
 }
 
-static int mc_device_remove(struct device *dev, struct subsys_interface *sif)
+static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
 {
 	int cpu = dev->id;
 
 	if (!cpu_online(cpu))
-		return 0;
+		return;
 
 	pr_debug("CPU%d removed\n", cpu);
 	microcode_fini_cpu(cpu);
 	sysfs_remove_group(&dev->kobj, &mc_attr_group);
-	return 0;
 }
 
 static struct subsys_interface mc_cpu_interface = {

drivers/base/base.h

@@ -63,7 +63,7 @@ struct driver_private {
  *	binding of drivers which were unable to get all the resources needed by
  *	the device; typically because it depends on another driver getting
  *	probed first.
- * @device - pointer back to the struct class that this structure is
+ * @device - pointer back to the struct device that this structure is
  * associated with.
  *
  * Nothing outside of the driver core should ever touch these fields.
@@ -134,6 +134,7 @@ extern int devres_release_all(struct device *dev);
 
 /* /sys/devices directory */
 extern struct kset *devices_kset;
+extern void devices_kset_move_last(struct device *dev);
 
 #if defined(CONFIG_MODULES) && defined(CONFIG_SYSFS)
 extern void module_add_driver(struct module *mod, struct device_driver *drv);

drivers/base/core.c

@@ -533,6 +533,52 @@ static DEVICE_ATTR_RO(dev);
 /* /sys/devices/ */
 struct kset *devices_kset;
 
+/**
+ * devices_kset_move_before - Move device in the devices_kset's list.
+ * @deva: Device to move.
+ * @devb: Device @deva should come before.
+ */
+static void devices_kset_move_before(struct device *deva, struct device *devb)
+{
+	if (!devices_kset)
+		return;
+	pr_debug("devices_kset: Moving %s before %s\n",
+		 dev_name(deva), dev_name(devb));
+	spin_lock(&devices_kset->list_lock);
+	list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
+	spin_unlock(&devices_kset->list_lock);
+}
+
+/**
+ * devices_kset_move_after - Move device in the devices_kset's list.
+ * @deva: Device to move
+ * @devb: Device @deva should come after.
+ */
+static void devices_kset_move_after(struct device *deva, struct device *devb)
+{
+	if (!devices_kset)
+		return;
+	pr_debug("devices_kset: Moving %s after %s\n",
+		 dev_name(deva), dev_name(devb));
+	spin_lock(&devices_kset->list_lock);
+	list_move(&deva->kobj.entry, &devb->kobj.entry);
+	spin_unlock(&devices_kset->list_lock);
+}
+
+/**
+ * devices_kset_move_last - move the device to the end of devices_kset's list.
+ * @dev: device to move
+ */
+void devices_kset_move_last(struct device *dev)
+{
+	if (!devices_kset)
+		return;
+	pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
+	spin_lock(&devices_kset->list_lock);
+	list_move_tail(&dev->kobj.entry, &devices_kset->list);
+	spin_unlock(&devices_kset->list_lock);
+}
+
 /**
  * device_create_file - create sysfs attribute file for device.
  * @dev: device.
@@ -1923,12 +1969,15 @@ int device_move(struct device *dev, struct device *new_parent,
 		break;
 	case DPM_ORDER_DEV_AFTER_PARENT:
 		device_pm_move_after(dev, new_parent);
+		devices_kset_move_after(dev, new_parent);
 		break;
 	case DPM_ORDER_PARENT_BEFORE_DEV:
 		device_pm_move_before(new_parent, dev);
+		devices_kset_move_before(new_parent, dev);
 		break;
 	case DPM_ORDER_DEV_LAST:
 		device_pm_move_last(dev);
+		devices_kset_move_last(dev);
 		break;
 	}
 

drivers/base/cpu.c

@@ -41,7 +41,7 @@ static void change_cpu_under_node(struct cpu *cpu,
 	cpu->node_id = to_nid;
 }
 
-static int __ref cpu_subsys_online(struct device *dev)
+static int cpu_subsys_online(struct device *dev)
 {
 	struct cpu *cpu = container_of(dev, struct cpu, dev);
 	int cpuid = dev->id;

drivers/base/dd.c

@@ -304,6 +304,14 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 			goto probe_failed;
 	}
 
+	/*
+	 * Ensure devices are listed in devices_kset in correct order
+	 * It's important to move Dev to the end of devices_kset before
+	 * calling .probe, because it could be recursive and parent Dev
+	 * should always go first
+	 */
+	devices_kset_move_last(dev);
+
 	if (dev->bus->probe) {
 		ret = dev->bus->probe(dev);
 		if (ret)

drivers/base/devres.c

@@ -297,10 +297,10 @@ void * devres_get(struct device *dev, void *new_res,
 	if (!dr) {
 		add_dr(dev, &new_dr->node);
 		dr = new_dr;
-		new_dr = NULL;
+		new_res = NULL;
 	}
 	spin_unlock_irqrestore(&dev->devres_lock, flags);
-	devres_free(new_dr);
+	devres_free(new_res);
 
 	return dr->data;
 }

drivers/base/firmware_class.c

@@ -443,7 +443,7 @@ static int fw_add_devm_name(struct device *dev, const char *name)
 		return -ENOMEM;
 	fwn->name = kstrdup_const(name, GFP_KERNEL);
 	if (!fwn->name) {
-		kfree(fwn);
+		devres_free(fwn);
 		return -ENOMEM;
 	}
 

drivers/cpufreq/cpufreq.c

@@ -1521,13 +1521,13 @@ static int __cpufreq_remove_dev_finish(struct device *dev)
  *
  * Removes the cpufreq interface for a CPU device.
  */
-static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
+static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
 {
 	unsigned int cpu = dev->id;
 	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
 
 	if (!policy)
-		return 0;
+		return;
 
 	if (cpu_online(cpu)) {
 		__cpufreq_remove_dev_prepare(dev);
@@ -1538,7 +1538,7 @@ static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
 
 	if (cpumask_empty(policy->real_cpus)) {
 		cpufreq_policy_free(policy, true);
-		return 0;
+		return;
 	}
 
 	if (cpu != policy->kobj_cpu) {
@@ -1557,8 +1557,6 @@ static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
 		policy->kobj_cpu = new_cpu;
 		WARN_ON(kobject_move(&policy->kobj, &new_dev->kobj));
 	}
-
-	return 0;
 }
 
 static void handle_update(struct work_struct *work)

drivers/net/rionet.c

@@ -396,7 +396,7 @@ static int rionet_close(struct net_device *ndev)
 	return 0;
 }
 
-static int rionet_remove_dev(struct device *dev, struct subsys_interface *sif)
+static void rionet_remove_dev(struct device *dev, struct subsys_interface *sif)
 {
 	struct rio_dev *rdev = to_rio_dev(dev);
 	unsigned char netid = rdev->net->hport->id;
@@ -416,8 +416,6 @@ static int rionet_remove_dev(struct device *dev, struct subsys_interface *sif)
 			}
 		}
 	}
-
-	return 0;
 }
 
 static void rionet_get_drvinfo(struct net_device *ndev,

include/linux/device.h

@@ -341,7 +341,7 @@ struct subsys_interface {
 	struct bus_type *subsys;
 	struct list_head node;
 	int (*add_dev)(struct device *dev, struct subsys_interface *sif);
-	int (*remove_dev)(struct device *dev, struct subsys_interface *sif);
+	void (*remove_dev)(struct device *dev, struct subsys_interface *sif);
 };
 
 int subsys_interface_register(struct subsys_interface *sif);

kernel/cpu.c

@@ -206,7 +206,7 @@ EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
 #endif	/* CONFIG_HOTPLUG_CPU */
 
 /* Need to know about CPUs going up/down? */
-int __ref register_cpu_notifier(struct notifier_block *nb)
+int register_cpu_notifier(struct notifier_block *nb)
 {
 	int ret;
 	cpu_maps_update_begin();
@@ -215,7 +215,7 @@ int __ref register_cpu_notifier(struct notifier_block *nb)
 	return ret;
 }
 
-int __ref __register_cpu_notifier(struct notifier_block *nb)
+int __register_cpu_notifier(struct notifier_block *nb)
 {
 	return raw_notifier_chain_register(&cpu_chain, nb);
 }
@@ -245,7 +245,7 @@ static void cpu_notify_nofail(unsigned long val, void *v)
 EXPORT_SYMBOL(register_cpu_notifier);
 EXPORT_SYMBOL(__register_cpu_notifier);
 
-void __ref unregister_cpu_notifier(struct notifier_block *nb)
+void unregister_cpu_notifier(struct notifier_block *nb)
 {
 	cpu_maps_update_begin();
 	raw_notifier_chain_unregister(&cpu_chain, nb);
@@ -253,7 +253,7 @@ void __ref unregister_cpu_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL(unregister_cpu_notifier);
 
-void __ref __unregister_cpu_notifier(struct notifier_block *nb)
+void __unregister_cpu_notifier(struct notifier_block *nb)
 {
 	raw_notifier_chain_unregister(&cpu_chain, nb);
 }
@@ -330,7 +330,7 @@ struct take_cpu_down_param {
 };
 
 /* Take this CPU down. */
-static int __ref take_cpu_down(void *_param)
+static int take_cpu_down(void *_param)
 {
 	struct take_cpu_down_param *param = _param;
 	int err;
@@ -349,7 +349,7 @@ static int __ref take_cpu_down(void *_param)
 }
 
 /* Requires cpu_add_remove_lock to be held */
-static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
+static int _cpu_down(unsigned int cpu, int tasks_frozen)
 {
 	int err, nr_calls = 0;
 	void *hcpu = (void *)(long)cpu;
@@ -443,7 +443,7 @@ out_release:
 	return err;
 }
 
-int __ref cpu_down(unsigned int cpu)
+int cpu_down(unsigned int cpu)
 {
 	int err;
 
@@ -633,7 +633,7 @@ void __weak arch_enable_nonboot_cpus_end(void)
 {
 }
 
-void __ref enable_nonboot_cpus(void)
+void enable_nonboot_cpus(void)
 {
 	int cpu, error;
 

tools/testing/selftests/firmware/fw_filesystem.sh

@@ -9,7 +9,15 @@ modprobe test_firmware
 
 DIR=/sys/devices/virtual/misc/test_firmware
 
-OLD_TIMEOUT=$(cat /sys/class/firmware/timeout)
+# CONFIG_FW_LOADER_USER_HELPER has a sysfs class under /sys/class/firmware/
+# These days no one enables CONFIG_FW_LOADER_USER_HELPER so check for that
+# as an indicator for CONFIG_FW_LOADER_USER_HELPER.
+HAS_FW_LOADER_USER_HELPER=$(if [ -d /sys/class/firmware/ ]; then echo yes; else echo no; fi)
+
+if [ "$HAS_FW_LOADER_USER_HELPER" = "yes" ]; then
+	OLD_TIMEOUT=$(cat /sys/class/firmware/timeout)
+fi
+
 OLD_FWPATH=$(cat /sys/module/firmware_class/parameters/path)
 
 FWPATH=$(mktemp -d)
@@ -17,7 +25,9 @@ FW="$FWPATH/test-firmware.bin"
 
 test_finish()
 {
-	echo "$OLD_TIMEOUT" >/sys/class/firmware/timeout
+	if [ "$HAS_FW_LOADER_USER_HELPER" = "yes" ]; then
+		echo "$OLD_TIMEOUT" >/sys/class/firmware/timeout
+	fi
 	echo -n "$OLD_PATH" >/sys/module/firmware_class/parameters/path
 	rm -f "$FW"
 	rmdir "$FWPATH"
@@ -25,8 +35,11 @@ test_finish()
 
 trap "test_finish" EXIT
 
-# Turn down the timeout so failures don't take so long.
-echo 1 >/sys/class/firmware/timeout
+if [ "$HAS_FW_LOADER_USER_HELPER" = "yes" ]; then
+	# Turn down the timeout so failures don't take so long.
+	echo 1 >/sys/class/firmware/timeout
+fi
+
 # Set the kernel search path.
 echo -n "$FWPATH" >/sys/module/firmware_class/parameters/path
 
@@ -41,7 +54,9 @@ if diff -q "$FW" /dev/test_firmware >/dev/null ; then
 	echo "$0: firmware was not expected to match" >&2
 	exit 1
 else
-	echo "$0: timeout works"
+	if [ "$HAS_FW_LOADER_USER_HELPER" = "yes" ]; then
+		echo "$0: timeout works"
+	fi
 fi
 
 # This should succeed via kernel load or will fail after 1 second after

tools/testing/selftests/firmware/fw_userhelper.sh

@@ -9,7 +9,17 @@ modprobe test_firmware
 
 DIR=/sys/devices/virtual/misc/test_firmware
 
-OLD_TIMEOUT=$(cat /sys/class/firmware/timeout)
+# CONFIG_FW_LOADER_USER_HELPER has a sysfs class under /sys/class/firmware/
+# These days no one enables CONFIG_FW_LOADER_USER_HELPER so check for that
+# as an indicator for CONFIG_FW_LOADER_USER_HELPER.
+HAS_FW_LOADER_USER_HELPER=$(if [ -d /sys/class/firmware/ ]; then echo yes; else echo no; fi)
+
+if [ "$HAS_FW_LOADER_USER_HELPER" = "yes" ]; then
+       OLD_TIMEOUT=$(cat /sys/class/firmware/timeout)
+else
+	echo "usermode helper disabled so ignoring test"
+	exit 0
+fi
 
 FWPATH=$(mktemp -d)
 FW="$FWPATH/test-firmware.bin"