2 files changed, 84 insertions, 63 deletions

diff --git a/drivers/gpio/gpio-ich.c b/drivers/gpio/gpio-ich.c
index 6f2306db8591..f9dbd503fc40 100644
--- a/drivers/gpio/gpio-ich.c
+++ b/drivers/gpio/gpio-ich.c
@@ -128,9 +128,9 @@ static int ichx_read_bit(int reg, unsigned nr)
         return data & (1 << bit) ? 1 : 0;
 }
 
-static int ichx_gpio_check_available(struct gpio_chip *gpio, unsigned nr)
+static bool ichx_gpio_check_available(struct gpio_chip *gpio, unsigned nr)
 {
-        return (ichx_priv.use_gpio & (1 << (nr / 32))) ? 0 : -ENXIO;
+        return ichx_priv.use_gpio & (1 << (nr / 32));
 }
 
 static int ichx_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index fff9786cdc64..c2534d62911c 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -88,13 +88,14 @@ static int gpiod_request(struct gpio_desc *desc, const char *label);
 static void gpiod_free(struct gpio_desc *desc);
 static int gpiod_direction_input(struct gpio_desc *desc);
 static int gpiod_direction_output(struct gpio_desc *desc, int value);
+static int gpiod_get_direction(const struct gpio_desc *desc);
 static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce);
-static int gpiod_get_value_cansleep(struct gpio_desc *desc);
+static int gpiod_get_value_cansleep(const struct gpio_desc *desc);
 static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value);
-static int gpiod_get_value(struct gpio_desc *desc);
+static int gpiod_get_value(const struct gpio_desc *desc);
 static void gpiod_set_value(struct gpio_desc *desc, int value);
-static int gpiod_cansleep(struct gpio_desc *desc);
-static int gpiod_to_irq(struct gpio_desc *desc);
+static int gpiod_cansleep(const struct gpio_desc *desc);
+static int gpiod_to_irq(const struct gpio_desc *desc);
 static int gpiod_export(struct gpio_desc *desc, bool direction_may_change);
 static int gpiod_export_link(struct device *dev, const char *name,
                              struct gpio_desc *desc);
@@ -171,12 +172,12 @@ static int gpio_ensure_requested(struct gpio_desc *desc)
         return 0;
 }
 
-/* caller holds gpio_lock *OR* gpio is marked as requested */
-static struct gpio_chip *gpiod_to_chip(struct gpio_desc *desc)
+static struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
 {
-        return desc->chip;
+        return desc ? desc->chip : NULL;
 }
 
+/* caller holds gpio_lock *OR* gpio is marked as requested */
 struct gpio_chip *gpio_to_chip(unsigned gpio)
 {
         return gpiod_to_chip(gpio_to_desc(gpio));
@@ -207,7 +208,7 @@ static int gpiochip_find_base(int ngpio)
 }
 
 /* caller ensures gpio is valid and requested, chip->get_direction may sleep  */
-static int gpiod_get_direction(struct gpio_desc *desc)
+static int gpiod_get_direction(const struct gpio_desc *desc)
 {
         struct gpio_chip        *chip;
         unsigned                offset;
@@ -223,11 +224,13 @@ static int gpiod_get_direction(struct gpio_desc *desc)
         if (status > 0) {
                 /* GPIOF_DIR_IN, or other positive */
                 status = 1;
-                clear_bit(FLAG_IS_OUT, &desc->flags);
+                /* FLAG_IS_OUT is just a cache of the result of get_direction(),
+                 * so it does not affect constness per se */
+                clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
         }
         if (status == 0) {
                 /* GPIOF_DIR_OUT */
-                set_bit(FLAG_IS_OUT, &desc->flags);
+                set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
         }
         return status;
 }
@@ -263,7 +266,7 @@ static DEFINE_MUTEX(sysfs_lock);
 static ssize_t gpio_direction_show(struct device *dev,
                 struct device_attribute *attr, char *buf)
 {
-        struct gpio_desc        *desc = dev_get_drvdata(dev);
+        const struct gpio_desc  *desc = dev_get_drvdata(dev);
         ssize_t                 status;
 
         mutex_lock(&sysfs_lock);
@@ -654,6 +657,11 @@ static ssize_t export_store(struct class *class,
                 goto done;
 
         desc = gpio_to_desc(gpio);
+        /* reject invalid GPIOs */
+        if (!desc) {
+                pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
+                return -EINVAL;
+        }
 
         /* No extra locking here; FLAG_SYSFS just signifies that the
          * request and export were done by on behalf of userspace, so
@@ -690,12 +698,14 @@ static ssize_t unexport_store(struct class *class,
         if (status < 0)
                 goto done;
 
-        status = -EINVAL;
-
         desc = gpio_to_desc(gpio);
         /* reject bogus commands (gpio_unexport ignores them) */
-        if (!desc)
-                goto done;
+        if (!desc) {
+                pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
+                return -EINVAL;
+        }
+
+        status = -EINVAL;
 
         /* No extra locking here; FLAG_SYSFS just signifies that the
          * request and export were done by on behalf of userspace, so
@@ -846,8 +856,10 @@ static int gpiod_export_link(struct device *dev, const char *name,
 {
         int                     status = -EINVAL;
 
-        if (!desc)
-                goto done;
+        if (!desc) {
+                pr_warn("%s: invalid GPIO\n", __func__);
+                return -EINVAL;
+        }
 
         mutex_lock(&sysfs_lock);
 
@@ -865,7 +877,6 @@ static int gpiod_export_link(struct device *dev, const char *name,
 
         mutex_unlock(&sysfs_lock);
 
-done:
         if (status)
                 pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
                          status);
@@ -896,8 +907,10 @@ static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
         struct device           *dev = NULL;
         int                     status = -EINVAL;
 
-        if (!desc)
-                goto done;
+        if (!desc) {
+                pr_warn("%s: invalid GPIO\n", __func__);
+                return -EINVAL;
+        }
 
         mutex_lock(&sysfs_lock);
 
@@ -914,7 +927,6 @@ static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
 unlock:
         mutex_unlock(&sysfs_lock);
 
-done:
         if (status)
                 pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
                          status);
@@ -940,8 +952,8 @@ static void gpiod_unexport(struct gpio_desc *desc)
         struct device           *dev = NULL;
 
         if (!desc) {
-                status = -EINVAL;
-                goto done;
+                pr_warn("%s: invalid GPIO\n", __func__);
+                return;
         }
 
         mutex_lock(&sysfs_lock);
@@ -962,7 +974,7 @@ static void gpiod_unexport(struct gpio_desc *desc)
                 device_unregister(dev);
                 put_device(dev);
         }
-done:
+
         if (status)
                 pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
                          status);
@@ -1384,12 +1396,13 @@ static int gpiod_request(struct gpio_desc *desc, const char *label)
         int                     status = -EPROBE_DEFER;
         unsigned long           flags;
 
-        spin_lock_irqsave(&gpio_lock, flags);
-
         if (!desc) {
-                status = -EINVAL;
-                goto done;
+                pr_warn("%s: invalid GPIO\n", __func__);
+                return -EINVAL;
         }
+
+        spin_lock_irqsave(&gpio_lock, flags);
+
         chip = desc->chip;
         if (chip == NULL)
                 goto done;
@@ -1432,8 +1445,7 @@ static int gpiod_request(struct gpio_desc *desc, const char *label)
 done:
         if (status)
                 pr_debug("_gpio_request: gpio-%d (%s) status %d\n",
-                         desc ? desc_to_gpio(desc) : -1,
-                         label ? : "?", status);
+                         desc_to_gpio(desc), label ? : "?", status);
         spin_unlock_irqrestore(&gpio_lock, flags);
         return status;
 }
@@ -1616,10 +1628,13 @@ static int gpiod_direction_input(struct gpio_desc *desc)
         int                     status = -EINVAL;
         int                     offset;
 
+        if (!desc) {
+                pr_warn("%s: invalid GPIO\n", __func__);
+                return -EINVAL;
+        }
+
         spin_lock_irqsave(&gpio_lock, flags);
 
-        if (!desc)
-                goto fail;
         chip = desc->chip;
         if (!chip || !chip->get || !chip->direction_input)
                 goto fail;
@@ -1655,13 +1670,9 @@ lose:
         return status;
 fail:
         spin_unlock_irqrestore(&gpio_lock, flags);
-        if (status) {
-                int gpio = -1;
-                if (desc)
-                        gpio = desc_to_gpio(desc);
-                pr_debug("%s: gpio-%d status %d\n",
-                        __func__, gpio, status);
-        }
+        if (status)
+                pr_debug("%s: gpio-%d status %d\n", __func__,
+                         desc_to_gpio(desc), status);
         return status;
 }
 
@@ -1678,6 +1689,11 @@ static int gpiod_direction_output(struct gpio_desc *desc, int value)
         int                     status = -EINVAL;
         int offset;
 
+        if (!desc) {
+                pr_warn("%s: invalid GPIO\n", __func__);
+                return -EINVAL;
+        }
+
         /* Open drain pin should not be driven to 1 */
         if (value && test_bit(FLAG_OPEN_DRAIN,  &desc->flags))
                 return gpiod_direction_input(desc);
@@ -1688,8 +1704,6 @@ static int gpiod_direction_output(struct gpio_desc *desc, int value)
 
         spin_lock_irqsave(&gpio_lock, flags);
 
-        if (!desc)
-                goto fail;
         chip = desc->chip;
         if (!chip || !chip->set || !chip->direction_output)
                 goto fail;
@@ -1725,13 +1739,9 @@ lose:
         return status;
 fail:
         spin_unlock_irqrestore(&gpio_lock, flags);
-        if (status) {
-                int gpio = -1;
-                if (desc)
-                        gpio = desc_to_gpio(desc);
-                pr_debug("%s: gpio-%d status %d\n",
-                        __func__, gpio, status);
-        }
+        if (status)
+                pr_debug("%s: gpio-%d status %d\n", __func__,
+                         desc_to_gpio(desc), status);
         return status;
 }
 
@@ -1753,10 +1763,13 @@ static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
         int                     status = -EINVAL;
         int                     offset;
 
+        if (!desc) {
+                pr_warn("%s: invalid GPIO\n", __func__);
+                return -EINVAL;
+        }
+
         spin_lock_irqsave(&gpio_lock, flags);
 
-        if (!desc)
-                goto fail;
         chip = desc->chip;
         if (!chip || !chip->set || !chip->set_debounce)
                 goto fail;
@@ -1776,13 +1789,9 @@ static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
 
 fail:
         spin_unlock_irqrestore(&gpio_lock, flags);
-        if (status) {
-                int gpio = -1;
-                if (desc)
-                        gpio = desc_to_gpio(desc);
-                pr_debug("%s: gpio-%d status %d\n",
-                        __func__, gpio, status);
-        }
+        if (status)
+                pr_debug("%s: gpio-%d status %d\n", __func__,
+                         desc_to_gpio(desc), status);
 
         return status;
 }
@@ -1824,12 +1833,14 @@ EXPORT_SYMBOL_GPL(gpio_set_debounce);
  * It returns the zero or nonzero value provided by the associated
  * gpio_chip.get() method; or zero if no such method is provided.
  */
-static int gpiod_get_value(struct gpio_desc *desc)
+static int gpiod_get_value(const struct gpio_desc *desc)
 {
         struct gpio_chip        *chip;
         int value;
         int offset;
 
+        if (!desc)
+                return 0;
         chip = desc->chip;
         offset = gpio_chip_hwgpio(desc);
         /* Should be using gpio_get_value_cansleep() */
@@ -1912,6 +1923,8 @@ static void gpiod_set_value(struct gpio_desc *desc, int value)
 {
         struct gpio_chip        *chip;
 
+        if (!desc)
+                return;
         chip = desc->chip;
         /* Should be using gpio_set_value_cansleep() */
         WARN_ON(chip->can_sleep);
@@ -1938,8 +1951,10 @@ EXPORT_SYMBOL_GPL(__gpio_set_value);
  * This is used directly or indirectly to implement gpio_cansleep().  It
  * returns nonzero if access reading or writing the GPIO value can sleep.
  */
-static int gpiod_cansleep(struct gpio_desc *desc)
+static int gpiod_cansleep(const struct gpio_desc *desc)
 {
+        if (!desc)
+                return 0;
         /* only call this on GPIOs that are valid! */
         return desc->chip->can_sleep;
 }
@@ -1959,11 +1974,13 @@ EXPORT_SYMBOL_GPL(__gpio_cansleep);
  * It returns the number of the IRQ signaled by this (input) GPIO,
  * or a negative errno.
  */
-static int gpiod_to_irq(struct gpio_desc *desc)
+static int gpiod_to_irq(const struct gpio_desc *desc)
 {
         struct gpio_chip        *chip;
         int                     offset;
 
+        if (!desc)
+                return -EINVAL;
         chip = desc->chip;
         offset = gpio_chip_hwgpio(desc);
         return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
@@ -1980,13 +1997,15 @@ EXPORT_SYMBOL_GPL(__gpio_to_irq);
  * Common examples include ones connected to I2C or SPI chips.
  */
 
-static int gpiod_get_value_cansleep(struct gpio_desc *desc)
+static int gpiod_get_value_cansleep(const struct gpio_desc *desc)
 {
         struct gpio_chip        *chip;
         int value;
         int offset;
 
         might_sleep_if(extra_checks);
+        if (!desc)
+                return 0;
         chip = desc->chip;
         offset = gpio_chip_hwgpio(desc);
         value = chip->get ? chip->get(chip, offset) : 0;
@@ -2005,6 +2024,8 @@ static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
         struct gpio_chip        *chip;
 
         might_sleep_if(extra_checks);
+        if (!desc)
+                return;
         chip = desc->chip;
         trace_gpio_value(desc_to_gpio(desc), 0, value);
         if (test_bit(FLAG_OPEN_DRAIN,  &desc->flags))