gpiolib: cdev: use blocking notifier call chain instead of atomic

Replace usage of atomic_notifier_call_chain with
blocking_notifier_call_chain as the notifier function,
lineinfo_changed_notify, calls gpio_desc_to_lineinfo,
which calls pinctrl_gpio_can_use_line, which can sleep.

The chain isn't being called from an atomic context so the
the blocking notifier is a suitable substitute.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index d50339e..352d815 100644 (file)
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -158,8 +158,8 @@ static long linehandle_set_config(struct linehandle_state *lh,
                                return ret;
                }
 
-               atomic_notifier_call_chain(&desc->gdev->notifier,
-                                          GPIOLINE_CHANGED_CONFIG, desc);
+               blocking_notifier_call_chain(&desc->gdev->notifier,
+                                            GPIOLINE_CHANGED_CONFIG, desc);
        }
        return 0;
 }
@@ -325,8 +325,8 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
                                goto out_free_descs;
                }
 
-               atomic_notifier_call_chain(&desc->gdev->notifier,
-                                          GPIOLINE_CHANGED_REQUESTED, desc);
+               blocking_notifier_call_chain(&desc->gdev->notifier,
+                                            GPIOLINE_CHANGED_REQUESTED, desc);
 
                dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
                        offset);
@@ -674,8 +674,8 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
        if (ret)
                goto out_free_desc;
 
-       atomic_notifier_call_chain(&desc->gdev->notifier,
-                                  GPIOLINE_CHANGED_REQUESTED, desc);
+       blocking_notifier_call_chain(&desc->gdev->notifier,
+                                    GPIOLINE_CHANGED_REQUESTED, desc);
 
        le->irq = gpiod_to_irq(desc);
        if (le->irq <= 0) {
@@ -1049,8 +1049,8 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file)
        priv->gdev = gdev;
 
        priv->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
-       ret = atomic_notifier_chain_register(&gdev->notifier,
-                                            &priv->lineinfo_changed_nb);
+       ret = blocking_notifier_chain_register(&gdev->notifier,
+                                              &priv->lineinfo_changed_nb);
        if (ret)
                goto out_free_bitmap;
 
@@ -1064,8 +1064,8 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file)
        return ret;
 
 out_unregister_notifier:
-       atomic_notifier_chain_unregister(&gdev->notifier,
-                                        &priv->lineinfo_changed_nb);
+       blocking_notifier_chain_unregister(&gdev->notifier,
+                                          &priv->lineinfo_changed_nb);
 out_free_bitmap:
        bitmap_free(priv->watched_lines);
 out_free_priv:
@@ -1085,8 +1085,8 @@ static int gpio_chrdev_release(struct inode *inode, struct file *file)
        struct gpio_device *gdev = priv->gdev;
 
        bitmap_free(priv->watched_lines);
-       atomic_notifier_chain_unregister(&gdev->notifier,
-                                        &priv->lineinfo_changed_nb);
+       blocking_notifier_chain_unregister(&gdev->notifier,
+                                          &priv->lineinfo_changed_nb);
        put_device(&gdev->dev);
        kfree(priv);
 

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 4d267c6..80137c1 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -615,7 +615,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 
        spin_unlock_irqrestore(&gpio_lock, flags);
 
-       ATOMIC_INIT_NOTIFIER_HEAD(&gdev->notifier);
+       BLOCKING_INIT_NOTIFIER_HEAD(&gdev->notifier);
 
 #ifdef CONFIG_PINCTRL
        INIT_LIST_HEAD(&gdev->pin_ranges);
@@ -2049,8 +2049,8 @@ static bool gpiod_free_commit(struct gpio_desc *desc)
        }
 
        spin_unlock_irqrestore(&gpio_lock, flags);
-       atomic_notifier_call_chain(&desc->gdev->notifier,
-                                  GPIOLINE_CHANGED_RELEASED, desc);
+       blocking_notifier_call_chain(&desc->gdev->notifier,
+                                    GPIOLINE_CHANGED_RELEASED, desc);
 
        return ret;
 }
@@ -3927,8 +3927,8 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
                return ERR_PTR(ret);
        }
 
-       atomic_notifier_call_chain(&desc->gdev->notifier,
-                                  GPIOLINE_CHANGED_REQUESTED, desc);
+       blocking_notifier_call_chain(&desc->gdev->notifier,
+                                    GPIOLINE_CHANGED_REQUESTED, desc);
 
        return desc;
 }
@@ -3995,8 +3995,8 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
                return ERR_PTR(ret);
        }
 
-       atomic_notifier_call_chain(&desc->gdev->notifier,
-                                  GPIOLINE_CHANGED_REQUESTED, desc);
+       blocking_notifier_call_chain(&desc->gdev->notifier,
+                                    GPIOLINE_CHANGED_REQUESTED, desc);
 
        return desc;
 }

diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index 2dee4e1..6709f79 100644 (file)
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -56,7 +56,7 @@ struct gpio_device {
        const char              *label;
        void                    *data;
        struct list_head        list;
-       struct atomic_notifier_head notifier;
+       struct blocking_notifier_head notifier;
 
 #ifdef CONFIG_PINCTRL
        /*