[PATCH v9 3/9] gpio: Add revocable provider handle for struct gpio_chip

Tzung-Bi Shih
2026-04-27T13:59:41Z

The underlying chip can be removed asynchronously. `gdev->srcu` is used
to ensure the synchronization before accessing `gdev->chip`.

Revocable encapsulates the details. Add revocable provider handle for
the corresponding struct gpio_chip in struct gpio_device so that it can
start to hide the synchronization details.

Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
---
v9:
- New to the series.
- Use static allocated resource provider.
- Rename "chip_rp" -> "chip_rev".

v4 - v8:
- Doesn't exist.

v3: https://lore.kernel.org/all/20260213092958.864411-8-tzungbi@kernel.org
- Change revocable API usages accordingly.

v2: https://lore.kernel.org/all/20260203061059.975605-8-tzungbi@kernel.org
- Change usages accordingly after applying
https://lore.kernel.org/all/20260129143733.45618-2-tzungbi@kernel.org.
- Add __rcu for `chip_rp`.
- Pass pointer of pointer to revocable_provider_revoke().
- Rebase accordingly after applying
https://lore.kernel.org/all/20260203060210.972243-1-tzungbi@kernel.org.

v1: https://lore.kernel.org/all/20260116081036.352286-13-tzungbi@kernel.org

---
drivers/gpio/gpiolib.c | 7 +++++++
drivers/gpio/gpiolib.h | 3 +++
2 files changed, 10 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 1e6dce430dca..20448d5aab93 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -23,6 +23,7 @@
#include <linux/nospec.h>
#include <linux/of.h>
#include <linux/pinctrl/consumer.h>
+#include <linux/revocable.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/srcu.h>
@@ -874,6 +875,7 @@ static void gpiodev_release(struct device *dev)
synchronize_srcu(&gdev->desc_srcu);
cleanup_srcu_struct(&gdev->desc_srcu);

+ revocable_embed_destroy(&gdev->chip_rev);
ida_free(&gpio_ida, gdev->id);
kfree_const(gdev->label);
kfree(gdev->descs);
@@ -1167,6 +1169,10 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
if (ret)
goto err_cleanup_desc_srcu;

+ ret = revocable_embed_init(&gdev->chip_rev, gc);
+ if (ret)
+ goto err_cleanup_desc_srcu;
+
device_initialize(&gdev->dev);
/*
* After this point any allocated resources to `gdev` will be
@@ -1389,6 +1395,7 @@ void gpiochip_remove(struct gpio_chip *gc)
/* Numb the device, cancelling all outstanding operations */
rcu_assign_pointer(gdev->chip, NULL);
synchronize_srcu(&gdev->srcu);
+ revocable_revoke(&gdev->chip_rev);
gpio_device_teardown_shared(gdev);
gpiochip_irqchip_remove(gc);
acpi_gpiochip_remove(gc);
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index dc4cb61a9318..4e2e98f61f5a 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -16,6 +16,7 @@
#include <linux/gpio/driver.h>
#include <linux/module.h>
#include <linux/notifier.h>
+#include <linux/revocable.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/srcu.h>
@@ -55,6 +56,7 @@ struct fwnode_handle;
* @device_notifier: used to notify character device wait queues about the GPIO
* device being unregistered
* @srcu: protects the pointer to the underlying GPIO chip
+ * @chip_rev: revocable provider handle for the corresponding struct gpio_chip.
* @pin_ranges: range of pins served by the GPIO driver
*
* This state container holds most of the runtime variable data
@@ -82,6 +84,7 @@ struct gpio_device {
struct workqueue_struct *line_state_wq;
struct blocking_notifier_head device_notifier;
struct srcu_struct srcu;
+ struct revocable chip_rev;

#ifdef CONFIG_PINCTRL
/*
--
2.51.0