1 files changed, 87 insertions, 89 deletions

diff --git a/drivers/gpio/gpio-virtuser.c b/drivers/gpio/gpio-virtuser.c
index 91b6352c957c..37f2ce20f1ae 100644
--- a/drivers/gpio/gpio-virtuser.c
+++ b/drivers/gpio/gpio-virtuser.c
@@ -11,7 +11,6 @@
 #include <linux/atomic.h>
 #include <linux/bitmap.h>
 #include <linux/cleanup.h>
-#include <linux/completion.h>
 #include <linux/configfs.h>
 #include <linux/debugfs.h>
 #include <linux/device.h>
@@ -37,6 +36,8 @@
 #include <linux/string_helpers.h>
 #include <linux/types.h>
 
+#include "dev-sync-probe.h"
+
 #define GPIO_VIRTUSER_NAME_BUF_LEN 32
 
 static DEFINE_IDA(gpio_virtuser_ida);
@@ -214,9 +215,7 @@ static int gpio_virtuser_set_array_value(struct gpio_descs *descs,
 	struct gpio_virtuser_irq_work_context ctx;
 
 	if (!atomic)
-		return gpiod_set_array_value_cansleep(descs->ndescs,
-						      descs->desc,
-						      descs->info, values);
+		return gpiod_multi_set_value_cansleep(descs, values);
 
 	gpio_virtuser_init_irq_work_context(&ctx);
 	ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_set_value_array_atomic);
@@ -400,10 +399,15 @@ static ssize_t gpio_virtuser_direction_do_write(struct file *file,
 	char buf[32], *trimmed;
 	int ret, dir, val = 0;
 
-	ret = simple_write_to_buffer(buf, sizeof(buf), ppos, user_buf, count);
+	if (count >= sizeof(buf))
+		return -EINVAL;
+
+	ret = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, user_buf, count);
 	if (ret < 0)
 		return ret;
 
+	buf[ret] = '\0';
+
 	trimmed = strim(buf);
 
 	if (strcmp(trimmed, "input") == 0) {
@@ -496,9 +500,7 @@ static int gpio_virtuser_value_set(void *data, u64 val)
 	if (val > 1)
 		return -EINVAL;
 
-	gpiod_set_value_cansleep(ld->ad.desc, (int)val);
-
-	return 0;
+	return gpiod_set_value_cansleep(ld->ad.desc, (int)val);
 }
 
 DEFINE_DEBUGFS_ATTRIBUTE(gpio_virtuser_value_fops,
@@ -539,7 +541,7 @@ static void gpio_virtuser_set_value_atomic(struct irq_work *work)
 	struct gpio_virtuser_irq_work_context *ctx =
 			to_gpio_virtuser_irq_work_context(work);
 
-	gpiod_set_value(ctx->desc, ctx->val);
+	ctx->ret = gpiod_set_value(ctx->desc, ctx->val);
 	complete(&ctx->work_completion);
 }
 
@@ -558,7 +560,7 @@ static int gpio_virtuser_value_atomic_set(void *data, u64 val)
 
 	gpio_virtuser_irq_work_queue_sync(&ctx);
 
-	return 0;
+	return ctx.ret;
 }
 
 DEFINE_DEBUGFS_ATTRIBUTE(gpio_virtuser_value_atomic_fops,
@@ -622,12 +624,15 @@ static ssize_t gpio_virtuser_consumer_write(struct file *file,
 	char buf[GPIO_VIRTUSER_NAME_BUF_LEN + 2];
 	int ret;
 
+	if (count >= sizeof(buf))
+		return -EINVAL;
+
 	ret = simple_write_to_buffer(buf, GPIO_VIRTUSER_NAME_BUF_LEN, ppos,
 				     user_buf, count);
 	if (ret < 0)
 		return ret;
 
-	buf[strlen(buf) - 1] = '\0';
+	buf[ret] = '\0';
 
 	ret = gpiod_set_consumer_name(data->ad.desc, buf);
 	if (ret)
@@ -973,49 +978,17 @@ static struct platform_driver gpio_virtuser_driver = {
 };
 
 struct gpio_virtuser_device {
+	struct dev_sync_probe_data probe_data;
 	struct config_group group;
 
-	struct platform_device *pdev;
 	int id;
 	struct mutex lock;
 
-	struct notifier_block bus_notifier;
-	struct completion probe_completion;
-	bool driver_bound;
-
 	struct gpiod_lookup_table *lookup_table;
 
 	struct list_head lookup_list;
 };
 
-static int gpio_virtuser_bus_notifier_call(struct notifier_block *nb,
-					   unsigned long action, void *data)
-{
-	struct gpio_virtuser_device *vdev;
-	struct device *dev = data;
-	char devname[32];
-
-	vdev = container_of(nb, struct gpio_virtuser_device, bus_notifier);
-	snprintf(devname, sizeof(devname), "gpio-virtuser.%d", vdev->id);
-
-	if (!device_match_name(dev, devname))
-		return NOTIFY_DONE;
-
-	switch (action) {
-	case BUS_NOTIFY_BOUND_DRIVER:
-		vdev->driver_bound = true;
-		break;
-	case BUS_NOTIFY_DRIVER_NOT_BOUND:
-		vdev->driver_bound = false;
-		break;
-	default:
-		return NOTIFY_DONE;
-	}
-
-	complete(&vdev->probe_completion);
-	return NOTIFY_OK;
-}
-
 static struct gpio_virtuser_device *
 to_gpio_virtuser_device(struct config_item *item)
 {
@@ -1029,7 +1002,7 @@ gpio_virtuser_device_is_live(struct gpio_virtuser_device *dev)
 {
 	lockdep_assert_held(&dev->lock);
 
-	return !!dev->pdev;
+	return !!dev->probe_data.pdev;
 }
 
 struct gpio_virtuser_lookup {
@@ -1369,7 +1342,7 @@ gpio_virtuser_device_config_dev_name_show(struct config_item *item,
 
 	guard(mutex)(&dev->lock);
 
-	pdev = dev->pdev;
+	pdev = dev->probe_data.pdev;
 	if (pdev)
 		return sprintf(page, "%s\n", dev_name(&pdev->dev));
 
@@ -1410,7 +1383,7 @@ gpio_virtuser_make_lookup_table(struct gpio_virtuser_device *dev)
 	size_t num_entries = gpio_virtuser_get_lookup_count(dev);
 	struct gpio_virtuser_lookup_entry *entry;
 	struct gpio_virtuser_lookup *lookup;
-	unsigned int i = 0;
+	unsigned int i = 0, idx;
 
 	lockdep_assert_held(&dev->lock);
 
@@ -1424,12 +1397,12 @@ gpio_virtuser_make_lookup_table(struct gpio_virtuser_device *dev)
 		return -ENOMEM;
 
 	list_for_each_entry(lookup, &dev->lookup_list, siblings) {
+		idx = 0;
 		list_for_each_entry(entry, &lookup->entry_list, siblings) {
-			table->table[i] =
+			table->table[i++] =
 				GPIO_LOOKUP_IDX(entry->key,
 						entry->offset < 0 ? U16_MAX : entry->offset,
-						lookup->con_id, i, entry->flags);
-			i++;
+						lookup->con_id, idx++, entry->flags);
 		}
 	}
 
@@ -1439,6 +1412,15 @@ gpio_virtuser_make_lookup_table(struct gpio_virtuser_device *dev)
 	return 0;
 }
 
+static void
+gpio_virtuser_remove_lookup_table(struct gpio_virtuser_device *dev)
+{
+	gpiod_remove_lookup_table(dev->lookup_table);
+	kfree(dev->lookup_table->dev_id);
+	kfree(dev->lookup_table);
+	dev->lookup_table = NULL;
+}
+
 static struct fwnode_handle *
 gpio_virtuser_make_device_swnode(struct gpio_virtuser_device *dev)
 {
@@ -1469,7 +1451,6 @@ gpio_virtuser_device_activate(struct gpio_virtuser_device *dev)
 {
 	struct platform_device_info pdevinfo;
 	struct fwnode_handle *swnode;
-	struct platform_device *pdev;
 	int ret;
 
 	lockdep_assert_held(&dev->lock);
@@ -1487,34 +1468,21 @@ gpio_virtuser_device_activate(struct gpio_virtuser_device *dev)
 	pdevinfo.fwnode = swnode;
 
 	ret = gpio_virtuser_make_lookup_table(dev);
-	if (ret) {
-		fwnode_remove_software_node(swnode);
-		return ret;
-	}
-
-	reinit_completion(&dev->probe_completion);
-	dev->driver_bound = false;
-	bus_register_notifier(&platform_bus_type, &dev->bus_notifier);
-
-	pdev = platform_device_register_full(&pdevinfo);
-	if (IS_ERR(pdev)) {
-		bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
-		fwnode_remove_software_node(swnode);
-		return PTR_ERR(pdev);
-	}
+	if (ret)
+		goto err_remove_swnode;
 
-	wait_for_completion(&dev->probe_completion);
-	bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
+	ret = dev_sync_probe_register(&dev->probe_data, &pdevinfo);
+	if (ret)
+		goto err_remove_lookup_table;
 
-	if (!dev->driver_bound) {
-		platform_device_unregister(pdev);
-		fwnode_remove_software_node(swnode);
-		return -ENXIO;
-	}
+	return 0;
 
-	dev->pdev = pdev;
+err_remove_lookup_table:
+	gpio_virtuser_remove_lookup_table(dev);
+err_remove_swnode:
+	fwnode_remove_software_node(swnode);
 
-	return 0;
+	return ret;
 }
 
 static void
@@ -1524,12 +1492,34 @@ gpio_virtuser_device_deactivate(struct gpio_virtuser_device *dev)
 
 	lockdep_assert_held(&dev->lock);
 
-	swnode = dev_fwnode(&dev->pdev->dev);
-	platform_device_unregister(dev->pdev);
+	swnode = dev_fwnode(&dev->probe_data.pdev->dev);
+	dev_sync_probe_unregister(&dev->probe_data);
+	gpio_virtuser_remove_lookup_table(dev);
 	fwnode_remove_software_node(swnode);
-	dev->pdev = NULL;
-	gpiod_remove_lookup_table(dev->lookup_table);
-	kfree(dev->lookup_table);
+}
+
+static void
+gpio_virtuser_device_lockup_configfs(struct gpio_virtuser_device *dev, bool lock)
+{
+	struct configfs_subsystem *subsys = dev->group.cg_subsys;
+	struct gpio_virtuser_lookup_entry *entry;
+	struct gpio_virtuser_lookup *lookup;
+
+	/*
+	 * The device only needs to depend on leaf lookup entries. This is
+	 * sufficient to lock up all the configfs entries that the
+	 * instantiated, alive device depends on.
+	 */
+	list_for_each_entry(lookup, &dev->lookup_list, siblings) {
+		list_for_each_entry(entry, &lookup->entry_list, siblings) {
+			if (lock)
+				WARN_ON(configfs_depend_item_unlocked(
+						subsys, &entry->group.cg_item));
+			else
+				configfs_undepend_item_unlocked(
+						&entry->group.cg_item);
+		}
+	}
 }
 
 static ssize_t
@@ -1544,15 +1534,24 @@ gpio_virtuser_device_config_live_store(struct config_item *item,
 	if (ret)
 		return ret;
 
-	guard(mutex)(&dev->lock);
+	if (live)
+		gpio_virtuser_device_lockup_configfs(dev, true);
 
-	if (live == gpio_virtuser_device_is_live(dev))
-		return -EPERM;
+	scoped_guard(mutex, &dev->lock) {
+		if (live == gpio_virtuser_device_is_live(dev))
+			ret = -EPERM;
+		else if (live)
+			ret = gpio_virtuser_device_activate(dev);
+		else
+			gpio_virtuser_device_deactivate(dev);
+	}
 
-	if (live)
-		ret = gpio_virtuser_device_activate(dev);
-	else
-		gpio_virtuser_device_deactivate(dev);
+	/*
+	 * Undepend is required only if device disablement (live == 0)
+	 * succeeds or if device enablement (live == 1) fails.
+	 */
+	if (live == !!ret)
+		gpio_virtuser_device_lockup_configfs(dev, false);
 
 	return ret ?: count;
 }
@@ -1725,8 +1724,7 @@ gpio_virtuser_config_make_device_group(struct config_group *group,
 				    &gpio_virtuser_device_config_group_type);
 	mutex_init(&dev->lock);
 	INIT_LIST_HEAD(&dev->lookup_list);
-	dev->bus_notifier.notifier_call = gpio_virtuser_bus_notifier_call;
-	init_completion(&dev->probe_completion);
+	dev_sync_probe_init(&dev->probe_data);
 
 	return &no_free_ptr(dev)->group;
 }