diff mbox

[v2,1/3] pinctrl: core: create nolock version of pinctrl_find_gpio_range_from_pin

Message ID 1456436679-22077-2-git-send-email-manabian@gmail.com
State New
Headers show

Commit Message

Joachim Eastwood Feb. 25, 2016, 9:44 p.m. UTC 
pinctrl_find_gpio_range_from_pin takes the pctldev->mutex but so
does pinconf_pins_show and this will cause a deadlock if
pinctrl_find_gpio_range_from_pin is used in .pin_config_get
callback.

Create a nolock version of pinctrl_find_gpio_range_from_pin to
allow pin to gpio lookup to be used from pinconf_pins_show.

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
---
 drivers/pinctrl/core.c | 35 +++++++++++++++++++++++------------
 drivers/pinctrl/core.h |  4 ++++
 2 files changed, 27 insertions(+), 12 deletions(-)

Comments

Linus Walleij March 7, 2016, 3:41 a.m. UTC | #1 
On Fri, Feb 26, 2016 at 4:44 AM, Joachim Eastwood <manabian@gmail.com> wrote:

> pinctrl_find_gpio_range_from_pin takes the pctldev->mutex but so
> does pinconf_pins_show and this will cause a deadlock if
> pinctrl_find_gpio_range_from_pin is used in .pin_config_get
> callback.
>
> Create a nolock version of pinctrl_find_gpio_range_from_pin to
> allow pin to gpio lookup to be used from pinconf_pins_show.
>
> Signed-off-by: Joachim Eastwood <manabian@gmail.com>

Excellent, patch applied.

Yours,
Linus Walleij
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diff mbox

Patch

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 2686a4450dfc..f67a8b7a4e18 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -481,18 +481,12 @@  int pinctrl_get_group_pins(struct pinctrl_dev *pctldev, const char *pin_group,
 }
 EXPORT_SYMBOL_GPL(pinctrl_get_group_pins);
 
-/**
- * pinctrl_find_gpio_range_from_pin() - locate the GPIO range for a pin
- * @pctldev: the pin controller device to look in
- * @pin: a controller-local number to find the range for
- */
 struct pinctrl_gpio_range *
-pinctrl_find_gpio_range_from_pin(struct pinctrl_dev *pctldev,
-				 unsigned int pin)
+pinctrl_find_gpio_range_from_pin_nolock(struct pinctrl_dev *pctldev,
+					unsigned int pin)
 {
 	struct pinctrl_gpio_range *range;
 
-	mutex_lock(&pctldev->mutex);
 	/* Loop over the ranges */
 	list_for_each_entry(range, &pctldev->gpio_ranges, node) {
 		/* Check if we're in the valid range */
@@ -500,15 +494,32 @@  pinctrl_find_gpio_range_from_pin(struct pinctrl_dev *pctldev,
 			int a;
 			for (a = 0; a < range->npins; a++) {
 				if (range->pins[a] == pin)
-					goto out;
+					return range;
 			}
 		} else if (pin >= range->pin_base &&
 			   pin < range->pin_base + range->npins)
-			goto out;
+			return range;
 	}
-	range = NULL;
-out:
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(pinctrl_find_gpio_range_from_pin_nolock);
+
+/**
+ * pinctrl_find_gpio_range_from_pin() - locate the GPIO range for a pin
+ * @pctldev: the pin controller device to look in
+ * @pin: a controller-local number to find the range for
+ */
+struct pinctrl_gpio_range *
+pinctrl_find_gpio_range_from_pin(struct pinctrl_dev *pctldev,
+				 unsigned int pin)
+{
+	struct pinctrl_gpio_range *range;
+
+	mutex_lock(&pctldev->mutex);
+	range = pinctrl_find_gpio_range_from_pin_nolock(pctldev, pin);
 	mutex_unlock(&pctldev->mutex);
+
 	return range;
 }
 EXPORT_SYMBOL_GPL(pinctrl_find_gpio_range_from_pin);
diff --git a/drivers/pinctrl/core.h b/drivers/pinctrl/core.h
index b24ea846c867..ca08723b9ee1 100644
--- a/drivers/pinctrl/core.h
+++ b/drivers/pinctrl/core.h
@@ -182,6 +182,10 @@  static inline struct pin_desc *pin_desc_get(struct pinctrl_dev *pctldev,
 	return radix_tree_lookup(&pctldev->pin_desc_tree, pin);
 }
 
+extern struct pinctrl_gpio_range *
+pinctrl_find_gpio_range_from_pin_nolock(struct pinctrl_dev *pctldev,
+					unsigned int pin);
+
 int pinctrl_register_map(struct pinctrl_map const *maps, unsigned num_maps,
 			 bool dup);
 void pinctrl_unregister_map(struct pinctrl_map const *map);