1 files changed, 73 insertions, 60 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 4c93cf73a826..44c8f5743a24 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2,7 +2,6 @@
 
 #include <linux/acpi.h>
 #include <linux/bitmap.h>
-#include <linux/cleanup.h>
 #include <linux/compat.h>
 #include <linux/debugfs.h>
 #include <linux/device.h>
@@ -16,7 +15,6 @@
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/module.h>
-#include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/seq_file.h>
@@ -83,9 +81,7 @@ DEFINE_SPINLOCK(gpio_lock);
 
 static DEFINE_MUTEX(gpio_lookup_lock);
 static LIST_HEAD(gpio_lookup_list);
-
 LIST_HEAD(gpio_devices);
-DECLARE_RWSEM(gpio_devices_sem);
 
 static DEFINE_MUTEX(gpio_machine_hogs_mutex);
 static LIST_HEAD(gpio_machine_hogs);
@@ -117,15 +113,20 @@ static inline void desc_set_label(struct gpio_desc *d, const char *label)
 struct gpio_desc *gpio_to_desc(unsigned gpio)
 {
 	struct gpio_device *gdev;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gpio_lock, flags);
 
-	scoped_guard(rwsem_read, &gpio_devices_sem) {
-		list_for_each_entry(gdev, &gpio_devices, list) {
-			if (gdev->base <= gpio &&
-			    gdev->base + gdev->ngpio > gpio)
-				return &gdev->descs[gpio - gdev->base];
+	list_for_each_entry(gdev, &gpio_devices, list) {
+		if (gdev->base <= gpio &&
+		    gdev->base + gdev->ngpio > gpio) {
+			spin_unlock_irqrestore(&gpio_lock, flags);
+			return &gdev->descs[gpio - gdev->base];
 		}
 	}
 
+	spin_unlock_irqrestore(&gpio_lock, flags);
+
 	if (!gpio_is_valid(gpio))
 		pr_warn("invalid GPIO %d\n", gpio);
 
@@ -398,21 +399,26 @@ static int gpiodev_add_to_list_unlocked(struct gpio_device *gdev)
 static struct gpio_desc *gpio_name_to_desc(const char * const name)
 {
 	struct gpio_device *gdev;
+	unsigned long flags;
 
 	if (!name)
 		return NULL;
 
-	guard(rwsem_read)(&gpio_devices_sem);
+	spin_lock_irqsave(&gpio_lock, flags);
 
 	list_for_each_entry(gdev, &gpio_devices, list) {
 		struct gpio_desc *desc;
 
 		for_each_gpio_desc(gdev->chip, desc) {
-			if (desc->name && !strcmp(desc->name, name))
+			if (desc->name && !strcmp(desc->name, name)) {
+				spin_unlock_irqrestore(&gpio_lock, flags);
 				return desc;
+			}
 		}
 	}
 
+	spin_unlock_irqrestore(&gpio_lock, flags);
+
 	return NULL;
 }
 
@@ -807,6 +813,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 			       struct lock_class_key *request_key)
 {
 	struct gpio_device *gdev;
+	unsigned long flags;
 	unsigned int i;
 	int base = 0;
 	int ret = 0;
@@ -871,46 +878,49 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 
 	gdev->ngpio = gc->ngpio;
 
-	scoped_guard(rwsem_write, &gpio_devices_sem) {
-		/*
-		 * TODO: this allocates a Linux GPIO number base in the global
-		 * GPIO numberspace for this chip. In the long run we want to
-		 * get *rid* of this numberspace and use only descriptors, but
-		 * it may be a pipe dream. It will not happen before we get rid
-		 * of the sysfs interface anyways.
-		 */
-		base = gc->base;
+	spin_lock_irqsave(&gpio_lock, flags);
 
+	/*
+	 * TODO: this allocates a Linux GPIO number base in the global
+	 * GPIO numberspace for this chip. In the long run we want to
+	 * get *rid* of this numberspace and use only descriptors, but
+	 * it may be a pipe dream. It will not happen before we get rid
+	 * of the sysfs interface anyways.
+	 */
+	base = gc->base;
+	if (base < 0) {
+		base = gpiochip_find_base_unlocked(gc->ngpio);
 		if (base < 0) {
-			base = gpiochip_find_base_unlocked(gc->ngpio);
-			if (base < 0) {
-				ret = base;
-				base = 0;
-				goto err_free_label;
-			}
-			/*
-			 * TODO: it should not be necessary to reflect the assigned
-			 * base outside of the GPIO subsystem. Go over drivers and
-			 * see if anyone makes use of this, else drop this and assign
-			 * a poison instead.
-			 */
-			gc->base = base;
-		} else {
-			dev_warn(&gdev->dev,
-				 "Static allocation of GPIO base is deprecated, use dynamic allocation.\n");
-		}
-		gdev->base = base;
-
-		ret = gpiodev_add_to_list_unlocked(gdev);
-		if (ret) {
-			chip_err(gc, "GPIO integer space overlap, cannot add chip\n");
+			spin_unlock_irqrestore(&gpio_lock, flags);
+			ret = base;
+			base = 0;
 			goto err_free_label;
 		}
+		/*
+		 * TODO: it should not be necessary to reflect the assigned
+		 * base outside of the GPIO subsystem. Go over drivers and
+		 * see if anyone makes use of this, else drop this and assign
+		 * a poison instead.
+		 */
+		gc->base = base;
+	} else {
+		dev_warn(&gdev->dev,
+			 "Static allocation of GPIO base is deprecated, use dynamic allocation.\n");
+	}
+	gdev->base = base;
 
-		for (i = 0; i < gc->ngpio; i++)
-			gdev->descs[i].gdev = gdev;
+	ret = gpiodev_add_to_list_unlocked(gdev);
+	if (ret) {
+		spin_unlock_irqrestore(&gpio_lock, flags);
+		chip_err(gc, "GPIO integer space overlap, cannot add chip\n");
+		goto err_free_label;
 	}
 
+	for (i = 0; i < gc->ngpio; i++)
+		gdev->descs[i].gdev = gdev;
+
+	spin_unlock_irqrestore(&gpio_lock, flags);
+
 	BLOCKING_INIT_NOTIFIER_HEAD(&gdev->line_state_notifier);
 	BLOCKING_INIT_NOTIFIER_HEAD(&gdev->device_notifier);
 	init_rwsem(&gdev->sem);
@@ -1001,8 +1011,9 @@ err_free_gpiochip_mask:
 		goto err_print_message;
 	}
 err_remove_from_list:
-	scoped_guard(rwsem_write, &gpio_devices_sem)
-		list_del(&gdev->list);
+	spin_lock_irqsave(&gpio_lock, flags);
+	list_del(&gdev->list);
+	spin_unlock_irqrestore(&gpio_lock, flags);
 err_free_label:
 	kfree_const(gdev->label);
 err_free_descs:
@@ -1065,7 +1076,7 @@ void gpiochip_remove(struct gpio_chip *gc)
 		dev_crit(&gdev->dev,
 			 "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
 
-	scoped_guard(rwsem_write, &gpio_devices_sem)
+	scoped_guard(spinlock_irqsave, &gpio_lock)
 		list_del(&gdev->list);
 
 	/*
@@ -1114,7 +1125,7 @@ struct gpio_device *gpio_device_find(void *data,
 	 */
 	might_sleep();
 
-	guard(rwsem_read)(&gpio_devices_sem);
+	guard(spinlock_irqsave)(&gpio_lock);
 
 	list_for_each_entry(gdev, &gpio_devices, list) {
 		if (gdev->chip && match(gdev->chip, data))
@@ -4725,33 +4736,35 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev)
 
 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
 {
+	unsigned long flags;
 	struct gpio_device *gdev = NULL;
 	loff_t index = *pos;
 
 	s->private = "";
 
-	guard(rwsem_read)(&gpio_devices_sem);
-
-	list_for_each_entry(gdev, &gpio_devices, list) {
-		if (index-- == 0)
+	spin_lock_irqsave(&gpio_lock, flags);
+	list_for_each_entry(gdev, &gpio_devices, list)
+		if (index-- == 0) {
+			spin_unlock_irqrestore(&gpio_lock, flags);
 			return gdev;
-	}
+		}
+	spin_unlock_irqrestore(&gpio_lock, flags);
 
 	return NULL;
 }
 
 static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
+	unsigned long flags;
 	struct gpio_device *gdev = v;
 	void *ret = NULL;
 
-	scoped_guard(rwsem_read, &gpio_devices_sem) {
-		if (list_is_last(&gdev->list, &gpio_devices))
-			ret = NULL;
-		else
-			ret = list_first_entry(&gdev->list, struct gpio_device,
-					       list);
-	}
+	spin_lock_irqsave(&gpio_lock, flags);
+	if (list_is_last(&gdev->list, &gpio_devices))
+		ret = NULL;
+	else
+		ret = list_first_entry(&gdev->list, struct gpio_device, list);
+	spin_unlock_irqrestore(&gpio_lock, flags);
 
 	s->private = "\n";
 	++*pos;