[PATCH 09/23] gpiolib: Ensure struct gpio_chip for gpiochip_setup_dev()

[Tzung-Bi Shih <tzungbi@kernel.org>]

Ensure struct gpio_chip for gpiochip_setup_dev().  This eliminates a few
checks for struct gpio_chip.

Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
---
 drivers/gpio/gpiolib-cdev.c  | 13 ++-----------
 drivers/gpio/gpiolib-cdev.h  |  3 ++-
 drivers/gpio/gpiolib-sysfs.c | 11 ++---------
 drivers/gpio/gpiolib-sysfs.h |  5 +++--
 drivers/gpio/gpiolib.c       | 24 +++++++++++++++++-------
 5 files changed, 26 insertions(+), 30 deletions(-)

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 66bd260c68e9..24449bbe38c9 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -2784,9 +2784,9 @@ static const struct file_operations gpio_fileops = {
 #endif
 };
 
-int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
+int gpiolib_cdev_register(struct gpio_device *gdev, struct gpio_chip *gc,
+			  dev_t devt)
 {
-	struct gpio_chip *gc;
 	int ret;
 
 	cdev_init(&gdev->chrdev, &gpio_fileops);
@@ -2802,18 +2802,9 @@ int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
 	if (ret)
 		goto err_free_workqueue;
 
-	guard(srcu)(&gdev->srcu);
-	gc = srcu_dereference(gdev->chip, &gdev->srcu);
-	if (!gc) {
-		ret = -ENODEV;
-		goto err_free_cdev;
-	}
-
 	gpiochip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);
 
 	return 0;
-err_free_cdev:
-	cdev_device_del(&gdev->chrdev, &gdev->dev);
 err_free_workqueue:
 	destroy_workqueue(gdev->line_state_wq);
 	return ret;
diff --git a/drivers/gpio/gpiolib-cdev.h b/drivers/gpio/gpiolib-cdev.h
index b42644cbffb8..16ef1e2e96a0 100644
--- a/drivers/gpio/gpiolib-cdev.h
+++ b/drivers/gpio/gpiolib-cdev.h
@@ -7,7 +7,8 @@
 
 struct gpio_device;
 
-int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt);
+int gpiolib_cdev_register(struct gpio_device *gdev, struct gpio_chip *gc,
+			  dev_t devt);
 void gpiolib_cdev_unregister(struct gpio_device *gdev);
 
 #endif /* GPIOLIB_CDEV_H */
diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 8e6b09d8b559..a4427a5cfa85 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -978,10 +978,9 @@ void gpiod_unexport(struct gpio_desc *desc)
 }
 EXPORT_SYMBOL_GPL(gpiod_unexport);
 
-int gpiochip_sysfs_register(struct gpio_device *gdev)
+int gpiochip_sysfs_register(struct gpio_device *gdev, struct gpio_chip *chip)
 {
 	struct gpiodev_data *data;
-	struct gpio_chip *chip;
 	struct device *parent;
 	int err;
 
@@ -994,12 +993,6 @@ int gpiochip_sysfs_register(struct gpio_device *gdev)
 	if (!class_is_registered(&gpio_class))
 		return 0;
 
-	guard(srcu)(&gdev->srcu);
-
-	chip = srcu_dereference(gdev->chip, &gdev->srcu);
-	if (!chip)
-		return -ENODEV;
-
 	/*
 	 * For sysfs backward compatibility we need to preserve this
 	 * preferred parenting to the gpio_chip parent field, if set.
@@ -1082,7 +1075,7 @@ static int gpiofind_sysfs_register(struct gpio_chip *gc, const void *data)
 	struct gpio_device *gdev = gc->gpiodev;
 	int ret;
 
-	ret = gpiochip_sysfs_register(gdev);
+	ret = gpiochip_sysfs_register(gdev, gc);
 	if (ret)
 		gpiochip_err(gc, "failed to register the sysfs entry: %d\n", ret);
 
diff --git a/drivers/gpio/gpiolib-sysfs.h b/drivers/gpio/gpiolib-sysfs.h
index 93debe8e118c..192b1ee041a6 100644
--- a/drivers/gpio/gpiolib-sysfs.h
+++ b/drivers/gpio/gpiolib-sysfs.h
@@ -7,13 +7,14 @@ struct gpio_device;
 
 #ifdef CONFIG_GPIO_SYSFS
 
-int gpiochip_sysfs_register(struct gpio_device *gdev);
+int gpiochip_sysfs_register(struct gpio_device *gdev, struct gpio_chip *chip);
 void gpiochip_sysfs_unregister(struct gpio_device *gdev,
 			       struct gpio_chip *chip);
 
 #else
 
-static inline int gpiochip_sysfs_register(struct gpio_device *gdev)
+static inline int gpiochip_sysfs_register(struct gpio_device *gdev,
+					  struct gpio_chip *chip)
 {
 	return 0;
 }
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index c3e1465042c4..efe72b81e131 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -882,14 +882,15 @@ static const struct device_type gpio_dev_type = {
 };
 
 #ifdef CONFIG_GPIO_CDEV
-#define gcdev_register(gdev, devt)	gpiolib_cdev_register((gdev), (devt))
+#define gcdev_register(gdev, gc, devt)	\
+		gpiolib_cdev_register((gdev), (gc), (devt))
 #define gcdev_unregister(gdev)		gpiolib_cdev_unregister((gdev))
 #else
 /*
  * gpiolib_cdev_register() indirectly calls device_add(), which is still
  * required even when cdev is not selected.
  */
-#define gcdev_register(gdev, devt)	device_add(&(gdev)->dev)
+#define gcdev_register(gdev, gc, devt)	device_add(&(gdev)->dev)
 #define gcdev_unregister(gdev)		device_del(&(gdev)->dev)
 #endif
 
@@ -897,7 +898,7 @@ static const struct device_type gpio_dev_type = {
  * An initial reference count has been held in gpiochip_add_data_with_key().
  * The caller should drop the reference via gpio_device_put() on errors.
  */
-static int gpiochip_setup_dev(struct gpio_device *gdev)
+static int gpiochip_setup_dev(struct gpio_device *gdev, struct gpio_chip *gc)
 {
 	struct fwnode_handle *fwnode = dev_fwnode(&gdev->dev);
 	int ret;
@@ -911,11 +912,11 @@ static int gpiochip_setup_dev(struct gpio_device *gdev)
 	if (fwnode && !fwnode->dev)
 		fwnode_dev_initialized(fwnode, false);
 
-	ret = gcdev_register(gdev, gpio_devt);
+	ret = gcdev_register(gdev, gc, gpio_devt);
 	if (ret)
 		return ret;
 
-	ret = gpiochip_sysfs_register(gdev);
+	ret = gpiochip_sysfs_register(gdev, gc);
 	if (ret)
 		goto err_remove_device;
 
@@ -962,13 +963,22 @@ static void machine_gpiochip_add(struct gpio_chip *gc)
 static void gpiochip_setup_devs(void)
 {
 	struct gpio_device *gdev;
+	struct gpio_chip *gc;
 	int ret;
 
 	guard(srcu)(&gpio_devices_srcu);
 
 	list_for_each_entry_srcu(gdev, &gpio_devices, list,
 				 srcu_read_lock_held(&gpio_devices_srcu)) {
-		ret = gpiochip_setup_dev(gdev);
+		guard(srcu)(&gdev->srcu);
+
+		gc = srcu_dereference(gdev->chip, &gdev->srcu);
+		if (!gc) {
+			dev_err(&gdev->dev, "Underlying GPIO chip is gone\n");
+			continue;
+		}
+
+		ret = gpiochip_setup_dev(gdev, gc);
 		if (ret) {
 			gpio_device_put(gdev);
 			dev_err(&gdev->dev,
@@ -1222,7 +1232,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 	 * (i.e., `gpio_bus_type` is ready).  Otherwise, defer until later.
 	 */
 	if (gpiolib_initialized) {
-		ret = gpiochip_setup_dev(gdev);
+		ret = gpiochip_setup_dev(gdev, gc);
 		if (ret)
 			goto err_teardown_shared;
 	}
-- 
2.52.0.457.g6b5491de43-goog