linux-kernel - [PATCH] gpio: don't warn about removing GPIO chips with active users anymore

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Date: Wed, 21 Feb 2024 11:21:03 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Bartosz Golaszewski <brgl@...ev.pl>,
	Kent Gibson <warthog618@...il.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Herve Codina <herve.codina@...tlin.com>
Cc: linux-gpio@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH] gpio: don't warn about removing GPIO chips with active users anymore

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

With SRCU we can now correctly handle the situation when a GPIO provider
is removed while having users still holding references to GPIO
descriptors. Remove all warnings emitted in this situation.

Suggested-by: Kent Gibson <warthog618@...il.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 drivers/gpio/gpiolib.c | 20 ++------------------
 1 file changed, 2 insertions(+), 18 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 3c22920bd201..63e793a410e3 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1106,7 +1106,6 @@ EXPORT_SYMBOL_GPL(gpiochip_add_data_with_key);
 void gpiochip_remove(struct gpio_chip *gc)
 {
 	struct gpio_device *gdev = gc->gpiodev;
-	unsigned int i;
 
 	/* FIXME: should the legacy sysfs handling be moved to gpio_device? */
 	gpiochip_sysfs_unregister(gdev);
@@ -1130,15 +1129,6 @@ void gpiochip_remove(struct gpio_chip *gc)
 	 */
 	gpiochip_set_data(gc, NULL);
 
-	for (i = 0; i < gdev->ngpio; i++) {
-		if (test_bit(FLAG_REQUESTED, &gdev->descs[i].flags))
-			break;
-	}
-
-	if (i != gdev->ngpio)
-		dev_crit(&gdev->dev,
-			 "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
-
 	/*
 	 * The gpiochip side puts its use of the device to rest here:
 	 * if there are no userspace clients, the chardev and device will
@@ -2329,10 +2319,9 @@ int gpiod_request(struct gpio_desc *desc, const char *label)
 	return ret;
 }
 
-static bool gpiod_free_commit(struct gpio_desc *desc)
+static void gpiod_free_commit(struct gpio_desc *desc)
 {
 	unsigned long flags;
-	bool ret = false;
 
 	might_sleep();
 
@@ -2357,23 +2346,18 @@ static bool gpiod_free_commit(struct gpio_desc *desc)
 #ifdef CONFIG_OF_DYNAMIC
 		WRITE_ONCE(desc->hog, NULL);
 #endif
-		ret = true;
 		desc_set_label(desc, NULL);
 		WRITE_ONCE(desc->flags, flags);
 
 		gpiod_line_state_notify(desc, GPIOLINE_CHANGED_RELEASED);
 	}
-
-	return ret;
 }
 
 void gpiod_free(struct gpio_desc *desc)
 {
 	VALIDATE_DESC_VOID(desc);
 
-	if (!gpiod_free_commit(desc))
-		WARN_ON(1);
-
+	gpiod_free_commit(desc);
 	module_put(desc->gdev->owner);
 	gpio_device_put(desc->gdev);
 }
-- 
2.40.1